ABSTRACT
Extracellular matrix (ECM) materials have had remarkable success as scaffolds in tissue engineering (TE) and as therapies for tissue injury whereby the ECM microenvironment promotes constructive remodeling and tissue regeneration. ECM powder and solubilized derivatives thereof have novel applications in TE and RM afforded by the capacity of these constructs to be dynamically modulated. The powder form allows for effective incorporation and penetration of reagents; hence, ECM powder is an efficacious platform for 3D cell culture and vehicle for small molecule delivery. ECM powder offers minimally invasive therapy for tissue injury and successfully treatment for wounds refractory to first-line therapies. Comminution of ECM and fabrication of powder-derived constructs, however, may compromise the biological integrity of the ECM. The current lack of optimized fabrication protocols prevents a more extensive and effective clinical application of ECM powders. Further study on methods of ECM powder fabrication and modification is needed.
KEYWORDS: comminution, extracellular matrix, powder, pulverization, regenerative medicine, tissue engineering
INTRODUCTION
Extracellular matrix (ECM) has been widely used in tissue engineering (TE) as a platform for de novo tissue formation and in regenerative medicine (RM) as a material to treat tissue injury by preventing scar formation and promoting constructive remodeling1 The current uses of ECM powder are examined with focus on the novel applications afforded by its particulate form. Means by which powdering improves efficacy of ECM treatment in specific tissues, challenges inherent to powder fabrication, and factors preventing further application of ECM powder are analyzed.
The ECM refers to a network of fibrous and gel-like materials produced by resident cells. It exists in a state of dynamic reciprocity providing signals and cues to cells which in turn modulate the composition and organization of the ECM.2 Specifically, the ECM creates a microenvironment that promotes constructive tissue remodeling, modulates gene expression and facilitates cell adhesion, migration, differentiation, and proliferation. 3
The interactions between cells and ECM motifs are highly important in determining cell fate and maintaining cellular phenotyp.4 In order to induce formation of the correct tissue at a specific site, the structure, composition, and source of ECM used must be considere.5 The macrostructure of ECM can be modified to suit the intended application. ECM may retain the conformation of the tissue it formerly surrounded or can be processed to form novel constructs.
ECM material that retains its original conformation, such as decellularized organs and sheets, provides the benefit of an intact vasculature, a precise mold of its derivative tissue, and preserved mechanical strengt.6 Although these forms of ECM undergo fewer processing steps, their clinical utility is somewhat limited because their structure prevents conformational adaptation.
ECM can be comminuted to yield powder which can be used in its particulate form or be enzymatically solubilized for use as a liquid or gel. ECM powder and powder-derived constructs (ECM liquid suspensions and gels) can fill areas of volumetric injury and conform to the contours of native tissues. The adaptable conformation of powder and its solubilized form allow for minimally invasive implantation such as injection. Unlike constructs with a fixed conformation which exhibit a proclivity to contract, particulate and solubilized ECM maintain the shape that is adopted.7
The adaptable form of powder is not only spatially advantageous, but also allows for efficient and homogenous conjugation to additional molecule. Powder can therefore act as a vehicle for delivery of cells, growth factors, and drugs. The dynamic properties of ECM powder render it effective in 3D bioprinting and treatment of a wide array of tissue injury. Although ECM powder and derived constructs seemingly offer infinite forms of application in TE and RM, challenges in fabrication and protocol optimization prevent a more extensive use.
Preparation of ECM powder involves extensive processing that potentially alters the biological integrity of the ECM. Steps in processing can affect the content, mechanical strength, ultrastructure and microstructure of the ECM.8 Preparation of powder ECM typically involves separation of the ECM from unwanted tissues, decellularization, freezing, lyophilization, pulverization, and milling. (Figure. 1) Conceivably, ECM components are disrupted at each step in fabrication and process may, in turn, alter the host response upon in vivo implantation.9
Despite widespread use of ECM powder, standard guidelines and sound methods for powder fabrication and treatment have not been defined. Fabrication and subsequent modification pose challenges to expanded application of ECM powders. This review examines the current uses of ECM powders and powder-derived constructs and challenges posed to expanding their applications in tissue engineering and regenerative medicine.
FABRICATION OF POWDER AND POWDER-DERIVED CONSTRUCTS
The fabrication process poses challenges to the effective use of ECM powder and powder-derived constructs. In general, preparation of ECM powder involves separation of the ECM from unwanted tissues, decellularization, freezing, lyophilization, pulverization, and milling (Figure. 1). The biological integrity of ECM can potentially be compromised at each step.8, 9 Moreover, comminution and subsequent solubilization can alter in vivo response after implantation. Pulverization of porcine urinary bladder (pUBM) has yielded a product with preserved ultrastructure and 3D characteristics of ECM, but this has not been consistently reproducible in all models.10 Despite reports of constructs exhibiting desired bioactivity, tissue specific parameters for optimal powder fabrication have not been determined. To optimize the utility ECM powder considerations should be given, but not limited to: the amount and concentration of powder used in constructs, particle size and morphology, powder solubilization, and ECM crosslinking. These methods and protocols must also be reproducible if these constructs are to be used in a clinical setting.
Powder concentration
The amount of ECM powder and concentration of said powder in liquids or gels influences the mechanical and physical properties of these constructs. The concentration of ECM powder in subsequently solubilized constructs affects porosity, compressive modulus, gelation threshold, and rheological properties. The amount of ECM material implanted can also affect the process of tissue remodeling. Notably, excessive ECM deposition in vivo can produce tissue fibrosis.11 Therefore, it is important to determine the appropriate quantity of ECM needed for regeneration and repair of specific tissues.
Scaffolds with a low ECM concentration are highly porous, but exhibit the tendency to contract. Increasing the concentration of ECM in a scaffold decreases the porosity but prevents significant scaffold contraction.12 Decreasing ECM concentration improves cellular adhesion and proliferation; hence there is a tradeoff between fabricating a scaffold that has greater biological activity and one that effectively fills areas of tissue deficit. 13
To create an effective scaffold, the concentration of ECM powder must therefore be adjusted to balance the poor cell-scaffold interactions of highly concentrated ECM scaffolds against the issue of contraction in scaffolds with a lower ECM concentration that have greater cell-scaffold interactions.
ECM concentration also influences gelation of solubilized powder and subsequent rheological properties of these gels. Hydrogels with higher concentrations of ECM exhibit a rigid structure with defined edges, whereas hydrogels with lower concentrations of ECM were more pliable and had rounder edges. Significantly, the effect of concentration on pore size of hydrogel was dependent upon the type of ECM used. The concentration of urinary bladder matrix (UBM) did not have any effect on hydrogel porosity, whereas increasing concentration of dermal ECM decreased hydrogel pore size. Therefore, the amount and concentration of ECM used is dependent upon the type of ECM used.14
Increasing the concentration of ECM increases the viscosity of powder suspensions causing gelation. The rheological properties of the resulting gels are highly significant clinically in that highly concentrated ECM hydrogels may not pass through needle lumen, preventing therapeutic injection.14 The properties of hydrogels have not been well characterized, but there is sufficient evidence to suggest that the concentration of ECM powder used in their fabrication has significant bearing on these properties. 14
Particle conformation
Despite biological composition, ECM powder can induce different changes in vivo depending on particle conformation. Specifically, size and morphology of ECM particles can influence cell proliferation, differentiation, tissue development.13,15,16 ECM powder has a wide distribution in particle size that is difficult to control.17 During powder preparation, residual moisture can induce clumping and agglomeration of powder can occur resulting in particles with numerous sizes. Separating agglomerations is difficult and clumps can be trapped in the milling process.18 Although particles with diverse shape and size are satisfactory substrates for cellular adhesion and growth,19 particles with uniform morphology allow for more control of tissue development in vivo. For example, use of powder with diverse particle sizes in skin TE diversity can manifest meshes with gaps which result in non-contiguous tissue formation that is cosmetically unaesthetic.17 Further study is needed to determine whether bioengineering of certain tissues may require specific particle sizes.
Sterilization
ECM biomaterials should be terminally sterilized before clinical use. Sterilization should effectively sanitize ECM by minimally destructive means. Many sterilization techniques and agents are used, including, but not limited to: gamma irradiation, electron-beam (e-beam), glutaraldehyde, ethylene oxide, peracetic acid (PAA.6 These methods have been assessed for their effect on the mechanical and biological integrity of ECM scaffolds, but have not been extensively studied in the context of ECM powder.
In general, ECM sterilization presents a challenge to manufactures: high temperatures denature matrix proteins,20 irradiation can degrade growth factors within in the matrix,21 and soluble reagents may not effectively penetrate the matrix.22
Specifically, sterilization of ECM powder requires further consideration because the effect of sterilization depends in part on whether ECM is hydrated or lyophilize.23 For example, sterilization of lyophilized ECM with ethylene oxide and e-beam altered mechanical properties and enzymatic digestion resistance of the ECM. Sterilization by the same means did not alter properties of hydrated ECM.24
Forms sterilization like PAA and ethanol that have limited effects on matrix properties, however, are not appropriate for powder. These aqueous forms of sterilization can alter particle size and morphology because powder may be solubilized or clum.25 Further study is needed to determine the best means of sterilizing ECM particles for clinical application of ECM powder to be expanded.
Solubilization
Powder is often solubilized enzymatically to make homogenous liquids or gels. Enzymatic digestion requires an acidic pH; therefore, solubilization commonly uses in hydrochloric acid or acetic acid. For in vivo use, acidic solubilized powder must be neutralized to physiological pH. If neutralization is not successful, the ECM will provide an acidic microenvironment that hinders vascularization and induces inflammation, granulation, and fibrosis.26
If enzymatic digestion was not sufficient or complete, particles may precipitate out of solution and the construct would have a heterogenous composition.18
Crosslinking and conjugation
Powder derived liquids and gels lack mechanical strength; therefore, ECM protein crosslinking is often used to strengthen their structure and inhibit degradation. Crosslinking is successfully strengthens hydrogels, but linker chemicals elicit a foreign body response in vivo.27
Additionally, crosslinking can be used to conjugate additional molecules (e.g., drugs, fluorescent markers) to the matrix. Carbodiimide crosslinkers such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) are often used to tether molecules to ECM collagen. EDC/NHS reaction with collagen, however, can leave toxic residues in the ECM.28
APPLICATIONS IN TISSUE ENGINEERING (TE)
ECM powder as a vehicle
Pulverized ECM offer a unique modality for the delivery of biologic products including growth factors and cells. Additionally, comminuted forms of ECM can be conjugated with pharmacologic agents to achieve more complex drug release profiles with greater tunability.
Cell delivery and cell culture
ECM powder and subsequently solubilized powder can both act as vehicles for 3D cell culture and minimally invasive cellular delivery to specific sites. 3D cell culture has been previously achieved in sponges, spheroids, hydrogels, and decellularized organs, but these platforms do not allow for uniform cell distribution or optimal nutrient diffusion.
Powdered ECM processed into cell-sized microparticles, however, would potentially allow cells to incorporate homogenously with and uniformly attach to the particulate scaffold yielding an improved 3D culture model. Given the large surface area to volume ratio of ECM particles, cellular attachment to ECM would be maximized. Unlike existing 3D culture models, the properties of an ECM particle mixture, such as particle size and concentration, could be modulated to regulate cell-cell and cell-matrix interactions.
Fabrication of ECM microparticles has not yet been achieved. Collagen, the most abundant protein of ECM, has been successfully comminuted to cell-sized microparticles which were able to form spheroids with primary rat hepatocytes.29 Basolateral cell-matrix and apical cell-cell interactions of multicellular spheroids induced cells to align radially and compactly in a single row fashion. The orientation of collagen-hepatocyte spheroids highlighted the potential of ECM microparticles to create 3D constructs with a complex microstructure. Further research on the effect comminution to a microparticle scale on the biological integrity of ECM is required. Formation of viable hepatocyte spheroids using collagen microparticles, however, suggests future potential of ECM microparticles.
Powdered ECM consisting of larger particles has already been used as cell carriers. Cells can be seeded directly on to powder19 or else suspended in a solution of solubilized powder. A cell-ECM suspension is particularly advantageous because it allows cells to be delivered via injection. Notably, grafts from injected solubilized ECM powder laden with human adipose-derived stem cells were superior to autologous adipose transplants which decreased in volume and size over time. Poor results from autologous grafts, which also contain native ECM, suggest that the use of solubilized particular ECM as a cell carrier conveys certain benefits that uncomminuted ECM may not.30
Cell culture in solubilized ECM powder may also be advantageous in promoting differentiation of progenitor cells. Study on cardiac muscle TE, demonstrated that induced pluripotent stem cells (iPSCs) can differentiate into mature cardiomyocytes when grown in solubilized cardiac ECM powder. iPSCs usually have the proclivity to differentiate into cardiomyocytes with a fetal phenotype. Deviation from the characteristic behavior of these cells indicates that solubilized ECM powder may provide a microenvironment that induces progenitor cells to terminally differentiate.31 Moreover, cells coated in solubilized ECM powdered derived from their native environment have exhibited increased levels of proliferation and differentiation as well as maintenance of the specific cell phenotype.32
As previously mentioned, ECM powder creates a 3D culture system in which cell-cell and cell-matrix interactions result in the unique assembly of cellular aggregates, such as spheroids. The ability of ECM powder to induce formation of cellular aggregates is significant because aggregates have been noted to function as a tissue unit. In a study on articular cartilage repair, mesenchymal stem cells incorporated with cartilage derived ECM powder formed functional “micro-cartilage” aggregates which induced hyaline like articular cartilage formation from of native stem cells and cells seeded on ECM particles. Significantly, ECM powder in this experiment provided a particulate carrier environment that could maintain the phenotype of chondrocytes which has the tendency to be lost over time. These aggregates were able to be delivered arthroscopically to sites of injury allowing for a one step, minimally invasive approach to cartilage repair.33
Drug delivery
Successful pharmaceutical treatment requires effective drug delivery. Polymeric scaffolds, have already shown potential as drug carriers.34 ECM powder, however, provides a more tunable and precise method of drug delivery. Powder can be homogenously conjugated with drugs to target specific sites in the body and to achieve more complex drug release profiles.
The bioavailability of drugs can be easily modulated by adjusting the concentration of ECM powder in the drug-ECM complex. Use of ECM powder in this manner has provided increased efficacy in controlled and sustained release of drugs.35
Drug conjugation to powder has been used to create 3D printed drugs, such as levetiracetam.36 3DP allows for control of spatial drug distribution and accurate drug dispense at low volumes, thereby reducing waste in manufacturing drugs and creating a highly tunable release profile.37, 38 ECM powders have not been used in drug 3DP, but their separate uses in drug delivery and 3DP indicates potential future application in drug 3DP.39
Novel use of a particulate system in a recent study on the treatment of non-small cell lung cancer identifies a drug delivery technique in which ECM powders may be applied. Nanoparticles and microparticles of chitosan encapsulated drug conjugated polyvinylpyrrolidone/maltodextrin were used as an inhalable treatment. Drug inhalation is non-invasive and specifically targets the lungs, preventing systemic adverse effects.40 ECM particles, which have been used in repair of lung tissue,41 may potentially be used in as an inhalable drug carrier but with increased efficacy owing to the bioactivity of ECM.
Growth factor delivery
ECM acts as a reservoir for cytokines and signaling molecules. As remodeling occurs, these molecules can be released. Given these properties, it follows that ECM can be used to deliver exogenous growth factors (GF) to areas in the body. ECM powders are particularly effective in delivery because they are easily modified and can be solubilized for injection to specific parts of the body.
Powder has been used to deliver growth factors to areas that are difficult to access directly, such as the liver. Previously growth factor delivery to hepatic parenchyma was achieved solely through vasculature. Recent study demonstrated that liver-derived ECM powder could carry GFs for their direct delivery to hepatic parenchyma to induce hepatocyte proliferation and liver regeneration. This is highly significant because liver regeneration occurs via adult hepatocyte expansion which is dependent upon GFs and ECM.42
Moreover, the powdered ECM has a high capacity to carry GFs and have good release profiles. An experiment on chondrogenesis using solubilized powdered ECM, increasing amounts of TGF-β3 were successfully loaded onto ECM which exhibited a release profile of GF that supported chondrogenesis well.13, 43
Powder conjugation
ECM powder is easily and homogenously modified. It can act as a conjugate in which it augments or “ornaments” synthetic polymers and surgical materials to mitigate an inflammatory response. Alternatively, it can serve as a substrate to which molecules are conjugated.
Molecular labelling
ECM powder serves as an excellent substrate for bioconjugate reactions because it allows for sufficient penetration of chemical reagents and homogenous mixing.44 Fluorescent labelling of ECM powder has been achieved by bioconjugate N-hydroxysuccinimide (NHS) reaction between fluorescent Cy3 molecules and matrix collagen. Significantly, fluorescently labelled solubilized powder allowed for real-time monitoring of scaffold degradation by minimally invasive injection which prevented destruction of samples.
ECM ornamentation
ECM powder has been successfully mixed with synthetic polymers to fabricate more biocompatible materials for use in TE and surgical wound closure. Specifically, dermal powder solubilized to make a hydrogel has been used to coat polypropylene surgical meshes. Polypropylene is non-degradable polymer which may elicit a foreign body response and significant inflammation. ECM ornamentation of the synthetic meshes, however, mitigates inflammation and subsequent fibrosis and scar tissue deposition. Modification by ECM hydrogel, which lacks mechanical strength, did not compromise the mechanical properties of surgical meshes. ECM ornamented surgical meshes were found to be effective in supporting weight bearing loads in the repair of ventral hernias, inguinal hernias and pelvic organ prolapse.45, 46 Polyurethane cardiac patches were coated with solubilized cardiac ECM powder. ECM prevented the progression of maladaptive remodeling after cardiac infarct and ultimately decreased left ventricular compliance, promoted angiogenesis, and prevented left ventricular dilatation, scarring, and thinning.47
ECM has also been used to coat synthetic polymer scaffolds. Solubilized small intestine submucosa (SIS) ECM powder was used to coat polylactic-co-glycolic acid (PLGA) for use in nucleus pulposus regeneration of intervertebral discs. PLGA, which yields an acidic degradation product, exhibited increased biocompatibility when augmented by SIS-ECM. There was more cellular adhesion to the composite SIS-ECM-PLGA scaffolds than to PLGA alone.48 Adding bone powder ECM to chitosan also increased bone regeneration and filled the area of bone defect better than a chitosan scaffold alone.49 ECM, which can self-assemble, has been mixed in the powdered form with inorganic materials that do not self-assemble. This has been particularly useful in bone microfiber formation which usually uses inorganic apatite matrices that do not self-assemble.50
3D PRINTING (3DP)
3DP is a bio-fabrication technique in which layer-by-layer assembly creates a complex 3D structure.51 Specifically, powder based 3DP has been used to make structurally complex scaffolds for application in TE.38 Powder is “printed” following the 2D template of each layer and then sprayed with a liquid binder to solidify the powder.
3DP powder substrates are commonly synthetic polymers which have limited biological activity and poor biocompatibility when compared to their naturally occurring counterparts. Although 3DP with synthetic polymers successfully yields complex 3D structures, the use of ECM powder increases biological activity of the construct.52
ECM powder can be solubilized and laden with cells to create “bio-ink” for use in 3DP. Bio-ink allows cells to be printed by preventing cellular damaging during the printing process. The viscosity of the solubilized ECM protects from shear stress induced apoptosis.53
Bio-ink, like powder, must be stabilized layer-by-layer as it is printed. Solidification of bio-ink is vital to stabilizing the 2D printed pattern and ultimately mimicking native ECM.6
Stabilization of synthetic powders necessitates the use of binder chemicals which leave toxic and acidic residues in the printed construct.3, 54 Bio-ink, however, can be solidified using non-toxic methods.
Recently, Jang et al developed a vitamin B2 induced crosslinking and thermal gelation method to crosslink ECM and subsequently stabilize bio-ink layer-by-layer during the printing process.55 Therefore, ECM powder use in 3DP potentially eliminates the need for toxic binders in stabilizing printed structures.
CLINICAL APPLICATIONS
ECM materials have numerous clinical applications in wound healing, surgical closure and reinforcement, and tissue reconstruction across large defects.56 Unlike cell-based TE therapies, ECM-based therapies account for the difference in microenvironment between injured tissue and healthy tissue and thereby promotes sufficient vascularization and innervation for increased wound healing.57 Therefore, ECM is efficacious in the treatment of wounds that are refractory to existing standard treatments and in patient populations, such as the elderly, who exhibit delayed wound healing.58 Wounds that exhibit delayed healing and the inability to have complete closure benefit from constructive tissue remodeling promoted by ECM treatment. Moreover, the mechanical properties of ECM help to maintain wound closure and support surgical anastomosis.
ECM sheets or “patches” have been used to treat partial trachea defects,59 volumetric muscle loss,60 septal ulceration,61 diabetic foot ulcers,62 and cartilage defects;63 to reinforce esophagojejunal anastomosis64and esophageal hiatal hernia repair;65 and to cover large defects from extensive surgical resection of cardiac tumors.66-68 ECM powder, however, has a potentially broader clinical application because it can assume any shape and its solubilized form can be delivered by minimally invasive injection.
Dry powder
Commercially available ECM powder, most prevalent of which is pUBM, has been used as both a primary therapy in tissue regeneration and an adjunctive therapy.
Closure and healing of wounds that are traditionally difficult to treat such as diabetic ulcers and radiation wounds has been achieved with the topical application of pUBM.69, 70 Suture-less wound closure has been achieved with ECM powder in which powder particles coalesce to form a thin adhesive film.71 Suture-less wound closure is significant because suture filaments can act as a nidus for wound infection. As an adjunctive therapy, ECM powder has been used to salvage head and neck flaps in which graft imbibition and inosculation failed.72
ECM powders have been used to bolster ECM sheet monotherapy treatment. The addition of powder treatment has been successful in treating refractory conditions such as pilonidal disease,73 diabetic foot ulcers,74 and primary and recurrent anal fistulas.75 In particular, pilonidal disease is challenging to treat: post-operative sacrococcygeal intergluteal wounds require daily open packing with wound dressings over the course of several months and repeated flap surgeries. ECM powder in combination of ECM sheets accelerated wound healing and closure, eliminating the need for flap surgery and daily dressing changes.76 Also, notably, ECM powder packing has provided novel and effective treatment for temporomandibular joint degeneration, which has never been successfully treated.77
Solubilized powder
ECM powder can be solubilized subsequently undergo gelation to form liquid and gels, respectively. ECM scaffold implantation typically requires open surgery, but the fluidity of liquid and rheological properties of gels allow for minimally invasive clinical application.6 Depending on the viscosity of the liquid or hydrogels, they can be injected in vivo to promote tissue repair and regeneration. ECM hydrogel injections have successfully regenerated tendons, cartilage, and skeletal muscles.,16, 78–80 exhibiting potential for the treatment of tendinopathies, muscle loss, cartilage degeneration, and promote meniscus repair.
ECM particles can be used to repair areas of damage and prevent further pathological change. ECM particle emulsions injection offers potential in restoring functional myocardium and preventing maladaptive remodeling after ischemic events. Although emulsions contain insolubilized ECM, they are included in this section because they possess liquid properties that allows for injection. In the case of ischemic heart failure, treatments are typically limited to invasive surgical procedures. Myocardial infarction results in a transient upregulation of metalloproteinases that degrade native ECM, ultimately promoting fibrosis and scar formation. Treatment with ECM counteracts these changes. Intramyocardial injection of particulate cardiac ECM promoted growth of new tissue, angiogenesis, LV wall thickening, and improved cardiac function.81 ECM biomaterials have been used in the form of patches and intravascular catheter delivered liquid—but these do not penetrate the myocardium directly.82 ECM emulsions, however, can be injected through the epicardium and into the myocardium at the site of ischemia.
Temperature and ECM concentration can be modulated to induce changes in ECM form at a certain time. Control over these variables allows for novel clinical application of solubilized ECM powder. In a stroke model, solubilized ECM can be injected into brain where it is induced to form a hydrogel at body temperature. The initial liquid form allows for easy injection, permeation throughout peri-infarcted areas of the brain, and conformation to the contours of the brain. Transformation into the hydrogel form at body temperature, however, ensures that the ECM remains inside the stroke cavity once in the body. Injection of UBM in this manner has been successful in remodeling infarcted brain and supporting endogenous repair mechanisms of surrounding penumbra.83 The same method has also been used in tendon regeneration in which the tendon ECM in liquid form was injected percutaneously and polymerized to form a fibrous hydrogel that was conducive for tendon regeneration.78
CONCLUSION
ECM powder has novel applications in TE and RM, overcoming limitations of ECM scaffolds that have predetermined structure. Powder can be packed, spread, sprayed, or solubilized for minimally invasive delivery by injection. In both dry and solubilized forms, it conforms to the contours of tissue and fills areas of volumetric injury. Moreover, ECM powder and powder-derived constructs maintain their assumed shape, and most significantly, their size. Uncomminuted ECM, however, has the proclivity to contract over time and may eventually fail to cover or fill voids.
In tissue engineering, powder provides an ideal platform for ECM modification and 3D cell-matrix interactions. Powder is easily penetrated allowing for optimal diffusion of nutrients, maximal cell adhesion, and homogenous incorporation of reagents. In this way, effective 3D cell culture and bioconjugate reaction with growth factors, drugs, and molecular markers is achieved. As powder is conveniently modified, it also acts to modify. ECM powder is used to modify synthetic materials that have poor biocompatibility. This is clinically significant because ECM coatings mitigate inflammation and foreign body reactions to synthetic implantable surgical devices.
ECM powder also augments biocompatibility in 3D bioprinting: powder derived printing substrates can be stabilized by novel non-toxic means. Use of ECM powder derived substrates may potentially eliminate the need for toxic chemical binders used in standard solidification and stabilization protocols.
Clinically, ECM powder avoids the need for invasive surgical procedures, which are standard protocol for implantation of ECM scaffolds with fixed structure. Powder can be solubilized for injectable treatment. Injection is not only minimally invasive, but also capable of targeting areas of tissue injury that are difficult to access surgically.
In general, ECM is able to treat tissue injuries that heal slowly or are refractory to first-line therapies. ECM powder, however, has specifically shown promise as a therapy for previously untreatable tissue degeneration. The exact mechanism by which the powder form of ECM is a successful treatment where uncomminuted forms are not is unknown. Adjunctive therapy with ECM powder has rendered other ECM treatments successful in multiple models, suggesting that powder provides specific benefits that uncomminuted ECM lack.
The utility of ECM powder is a double-edged sword: advantageous properties that allow for novel application present challenges to further application. ECM powder and its solubilized derivatives can assume any shape; however, the destruction of the original 3D architecture that affords this may compromise the biological integrity of the ECM. Use of ECM powder in creating scaffolds provides incredible control over the construct’s characteristics. But, inherent in the ability to modulate characteristics and composition of powder-derived constructs is that any resulting construct will not ideally biomimetic.
Fabrication of ECM powder is challenging and highly susceptible to error at multiple levels. It is difficult to control particle size: powder is prone to agglomerating and cannot be effectively separated after initial comminution. Solubilization requires acidic conditions, which can elicit inflammation in vivo if not appropriately neutralized. Methods of sterilization are limited: aqueous solutions dissolve the powder. Problems at these key steps in fabrication need to be resolved for ECM powder to be used more extensively.
ECM powder may have greater potential as a biological therapy if more is known about the effect of comminution on ECM and if optimal fabrication protocols are determined. Further study on the modulation of ECM particles properties, may also inform for the design of tissue specific therapies.
Funding Statement
This work was supported by the No funding;
Abbreviations
- 3DP
3-Dimensional printing
- e-beam
electron-beam
- ECM
extracellular matrix
- EDC
1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride
- GF
growth factor
- iPSC
induced pluripotent stem cell
- NHS
N-hydroxysuccinimide
- PAA
peracetic acid
- RM
regenerative medicine
- SIS
small intestine submucosa
- TE
tissue engineering
- UBM
urinary bladder matrix
Article highlights
Compared to their uncomminuted counterparts, ECM powders overcome challenges in and act as efficacious substrates for homogenous bioconjugate modification, 3D bioprinting, and treatment of intransigent tissue injury.
Pulverization of ECM to a powder form affords structural flexibility that allows for novel applications in TE and RM.
Of note, conformational adaptation to tissue contours and resistance to contraction enable ECM powder and solubilized derivatives effectively fill areas of tissue void.
ECM powder can be uniformly incorporated with cells to optimize 3D cell culture and homogenously modified to effectively carry small molecules such as drugs and growth factors.
Furthermore, ECM powder is used as a primary or adjunctive minimally invasive therapy by which it accelerates wound healing, facilitates complete wound closure, and salvages failed grafts.
Improving methods of powder fabrication, solubilization, sterilization, and crosslinking represents the most significant challenges to the effective and extended clinical use of ECM powders.
References
- 1.Brown BN, Badylak SF.. Extracellular matrix as an inductive scaffold for functional tissue reconstruction. Transl Res J Lab Clin Med. 2014;163:268–285. doi: 10.1016/j.trsl.2013.11.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Marçal H, Ahmed T, Badylak SF, Tottey S, Foster LJR. A comprehensive protein expression profile of extracellular matrix biomaterial derived from porcine urinary bladder. Regen Med. 2012;7:159–166. doi: 10.2217/rme.12.6. [DOI] [PubMed] [Google Scholar]
- 3.Brunello G, Sivolella S, Meneghello R, Ferroni L, Gardin C, Piattelli A, Zavan B, Bressan E. Powder-based 3D printing for bone tissue engineering. Biotechnol Adv. 2016;34:740–753. doi: 10.1016/j.biotechadv.2016.03.009. [DOI] [PubMed] [Google Scholar]
- 4.Ahmed M, Ffrench-Constant C. Extracellular matrix regulation of stem cell behavior. Curr Stem Cell Rep. 2016;2:197–206. doi: 10.1007/s40778-016-0041-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Londono R, Badylak SF. Biologic scaffolds for regenerative medicine: mechanisms of in vivo remodeling. Ann Biomed Eng. 2014;43:577–592. doi: 10.1007/s10439-014-1103-8. [DOI] [PubMed] [Google Scholar]
- 6.Orlando G, editor. Regenerative medicine applications in organ transplantation. 1st ed. Amsterdam; Boston: (MA): Elsevier Academic Press; 2014. [Google Scholar]
- 7.Visscher DO, Bos EJ, Peeters M, Kuzmin NV, Groot ML, Helder MN, Van Zuijlen PPM. Cartilage tissue engineering: preventing tissue scaffold contraction using a 3D-printed polymeric cage. Tissue Eng Part C Methods. 2016. doi: 10.1089/ten.tec.2016.0073. [DOI] [PubMed] [Google Scholar]
- 8.Reing JE, Brown BN, Daly KA, Wey S-P, Juang J-H, Nguyen H-N, Hsu C-W, Lin K-J, Sung H-W. The effects of processing methods upon mechanical and biologic properties of porcine dermal extracellular matrix scaffolds. Biomaterials. 2010;31:8626–8633. doi: 10.1016/j.biomaterials.2010.01.042. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Badylak SF, Freytes DO, Gilbert TW. Reprint of: extracellular matrix as a biological scaffold material: structure and function. Acta Biomater. 2015;23:Supplement:S17–S26. doi: 10.1016/j.actbio.2015.07.016. [DOI] [PubMed] [Google Scholar]
- 10.Penolazzi L, Mazzitelli S, Vecchiatini R, Torreggiani E, Lambertini E, Johnson S, Badylak SF, Piva R, Nastruzzi C. Human mesenchymal stem cells seeded on extracellular matrix-scaffold: viability and osteogenic potential. J Cell Physiol. 2012;227:857–866. doi: 10.1002/jcp.22983. [DOI] [PubMed] [Google Scholar]
- 11.Zhang Q, Shang -M-M, Ling Q-F, Wu X-P, Liu C-Y. Hepatoprotective effects of loach (Misgurnus anguillicaudatus) lyophilized powder on dimethylnitrosamine-induced liver fibrosis in rats. Arch Pharm Res. 2014. doi: 10.1007/s12272-014-0445-y. [DOI] [PubMed] [Google Scholar]
- 12.Chang C-H, Chen -C-C, Liao C-H, Ye J, Zhai H, Chen Y, Zhang L, Zeng Y. Human acellular cartilage matrix powders as a biological scaffold for cartilage tissue engineering with synovium-derived mesenchymal stem cells. J Biomed Mater Res A. 2014;102:2248–2257. doi: 10.1002/jbm.a.34788. [DOI] [PubMed] [Google Scholar]
- 13.Almeida HV, Cunniffe GM, Vinardell T, Buckley CT, O’Brien FJ, Kelly DJ. Coupling freshly isolated CD44(+) infrapatellar fat pad-derived stromal cells with a TGF-β3 eluting cartilage ECM-derived scaffold as a single-stage strategy for promoting chondrogenesis. Adv Healthc Mater. 2015;4:1043–1053. doi: 10.1002/adhm.v4.7. [DOI] [PubMed] [Google Scholar]
- 14.Wolf MT, Daly KA, Brennan-Pierce EP, Johnson SA, Carruthers CA, D’Amore A, Nagarkar SP, Velankar SS, Badylak SF. A hydrogel derived from decellularized dermal extracellular matrix. Biomaterials. 2012;33:7028–7038. doi: 10.1016/j.biomaterials.2012.06.051. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Thitiset T, Damrongsakkul S, Bunaprasert T, Leeanansaksiri W, Honsawek S. Development of collagen/demineralized bone powder scaffolds and periosteum-derived cells for bone tissue engineering application. Int J Mol Sci. 2013;14:2056–2071. doi: 10.3390/ijms14012056. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Almeida HV, Eswaramoorthy R, Cunniffe GM, Buckley CT, O’Brien FJ, Kelly DJ. Fibrin hydrogels functionalized with cartilage extracellular matrix and incorporating freshly isolated stromal cells as an injectable for cartilage regeneration. Acta Biomater. 2016;36:55–62. doi: 10.1016/j.actbio.2016.03.008. [DOI] [PubMed] [Google Scholar]
- 17.Zuo H, Peng D, Zheng B, Liu X, Wang Y, Wang L, Zhou X, Liu J. Regeneration of mature dermis by transplanted particulate acellular dermal matrix in a rat model of skin defect wound. J Mater Sci Mater Med. 2012;23:2933–2944. doi: 10.1007/s10856-012-4745-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Seif-Naraghi S, Singelyn J, Dequach J, Schup-Magoffin P, Christman K. Fabrication of biologically derived injectable materials for myocardial tissue engineering. J Vis Exp JoVE. 2010. doi: 10.3791/2109. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Cha P-F, Gao J-H, Chen Y, Lu F. [Construction of scaffold with human extracellular matrix from adipose tissue]. Zhonghua Zheng Xing Wai Ke Za Zhi Zhonghua Zhengxing Waike Zazhi Chin. J Plast Surg. 2012;28(1):55–60. [PubMed] [Google Scholar]
- 20.Sun WQ, Xu H, Sandor M, Lombardi J. Process-induced extracellular matrix alterations affect the mechanisms of soft tissue repair and regeneration. J Tissue Eng. 2013;4:1–13. doi: 10.1177/2041731413505305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Gothard D, Smith EL, Kanczler JM, Black CR, Wells JA, Roberts CA, White LJ, Qutachi O, Peto H, Rashidi H, et al. In vivo assessment of bone regeneration in alginate/bone ECM hydrogels with incorporated skeletal stem cells and single growth factors. PLoS One. 2015;10:e0145080. doi: 10.1371/journal.pone.0145080. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Katzner L. Xenograft sourcing and manufacturing, challenges, and opportunities. In: Mooradian DL, editor. Extracellular matrix-derived implants in clinical medicine Cambridge (MA): Woodhead Publishing; 2016. p. 139–150. [Google Scholar]
- 23.Dearth CL, Keane TJ, Carruthers CA, Reing JE, Huleihel L, Ranallo CA, Kollar EW, Badylak SF. The effect of terminal sterilization on the material properties and in vivo remodeling of a porcine dermal biologic scaffold. Acta Biomater. 2016;33:78–87. doi: 10.1016/j.actbio.2016.01.038. [DOI] [PubMed] [Google Scholar]
- 24.Proffen BL, Perrone GS, Fleming BC, Sieker JT, Kramer J, Hawes ML, Murray MM. Effect of low-temperature ethylene oxide and electron beam sterilization on the in vitro and in vivo function of reconstituted extracellular matrix-derived scaffolds. J Biomater Appl. 2015;30:435–449. doi: 10.1177/0885328215590967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Matuska AM, McFetridge PS. The effect of terminal sterilization on structural and biophysical properties of a decellularized collagen-based scaffold; implications for stem cell adhesion. J Biomed Mater Res B Appl Biomater. 2015;103:397–406. doi: 10.1002/jbm.b.33213. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Edgar L, McNamara K, Wong T, Tamburrini R, Katari R, Orlando G. Heterogeneity of scaffold biomaterials in tissue engineering. Materials. 2016;9:332. doi: 10.3390/ma9050332. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Beck EC, Barragan M, Tadros MH, Gehrke SH, Detamore MS. Approaching the compressive modulus of articular cartilage with a decellularized cartilage-based hydrogel. Acta Biomater. 2016;38:94–105. doi: 10.1016/j.actbio.2016.04.019. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Parenteau-Bareil R, Gauvin R, Berthod F. Collagen-based biomaterials for tissue engineering applications. Materials. 2010;3:1863–1887. doi: 10.3390/ma3031863. [DOI] [Google Scholar]
- 29.Yamada M, Hori A, Sugaya S, Yajima Y, Utoh R, Yamato M, Seki M. Cell-sized condensed collagen microparticles for preparing microengineered composite spheroids of primary hepatocytes. Lab Chip. 2015;15:3941–3951. doi: 10.1039/C5LC00785B. [DOI] [PubMed] [Google Scholar]
- 30.Choi JS, Yang H-J, Kim BS, Kim JD, Kim JY, Yoo B, Park K, Lee HY, Cho YW. Human extracellular matrix (ECM) powders for injectable cell delivery and adipose tissue engineering. J Control Release. 2009;139:2–7. doi: 10.1016/j.jconrel.2009.05.034. [DOI] [PubMed] [Google Scholar]
- 31.Fong AH, Romero-López M, Heylman CM, Keating M, Tran D, Sobrino A, Tran AQ, Pham HH, Fimbres C, Gershon PD, et al. Three-dimensional adult cardiac extracellular matrix promotes maturation of human induced pluripotent stem cell-derived cardiomyocytes. Tissue Eng Part A. 2016;22:1016–1025. doi: 10.1089/ten.tea.2016.0027. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32.Zhang Y, He Y, Bharadwaj S, Hammam N, Carnagey K, Myers R, Atala A, Van Dyke M. Tissue-specific extracellular matrix coatings for the promotion of cell proliferation and maintenance of cell phenotype. Biomaterials. 2009;30:4021–4028. doi: 10.1016/j.biomaterials.2009.04.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Yin H, Wang Y, Sun Z, Sun X, Xu Y, Li P, Meng H, Yu X, Xiao B, Fan T, et al. Induction of mesenchymal stem cell chondrogenic differentiation and functional cartilage microtissue formation for in vivo cartilage regeneration by cartilage extracellular matrix-derived particles. Acta Biomater. 2016;33:96–109. doi: 10.1016/j.actbio.2016.01.024. [DOI] [PubMed] [Google Scholar]
- 34.Garg T, Singh O, Arora S, Murthy RSR. Scaffold: a novel carrier for cell and drug delivery. Crit Rev Ther Drug Carrier Syst. 2012;29:1–63. doi: 10.1615/CritRevTherDrugCarrierSyst.v29.i1. [DOI] [PubMed] [Google Scholar]
- 35.Kwon JS, Yoon SM, Shim SW, Tong Y, Guo L, Hu X, Gao X, Yao W. Injectable extracellular matrix hydrogel developed using porcine articular cartilage. Int J Pharm. 2013;454:183–191. doi: 10.1016/j.ijpharm.2013.06.059. [DOI] [PubMed] [Google Scholar]
- 36.Boudriau S, Hanzel C, Massicotte J, Sayegh L, Wang J, Lefebvre M. Randomized comparative bioavailability of a novel three-dimensional printed fast-melt formulation of levetiracetam following the administration of a single 1000-mg dose to healthy human volunteers under fasting and fed conditions. Drugs RD. 2016;16:229–238. doi: 10.1007/s40268-016-0132-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37.Ursan ID, Chiu L, Pierce A. Three-dimensional drug printing: A structured review. J Am Pharm Assoc. 2013;53:136–144. doi: 10.1331/JAPhA.2013.12217. [DOI] [PubMed] [Google Scholar]
- 38.Alhnan MA, Okwuosa TC, Sadia M, Wan K-W, Ahmed W, Arafat B. Emergence of 3D printed dosage forms: opportunities and challenges. Pharm Res. 2016;33(8):1817–1832. doi: 10.1007/s11095-016-1933-1. [DOI] [PubMed] [Google Scholar]
- 39.Prasad LK, Smyth H. 3D printing technologies for drug delivery: a review. Drug Dev Ind Pharm. 2016;42:1019–1031. doi: 10.3109/03639045.2016.1173052. [DOI] [PubMed] [Google Scholar]
- 40.Abbas Y, Azzazy HME, Tammam S, Lamprecht A, Ali ME, Schmidt A, Sollazzo S, Mathur S. Development of an inhalable, stimuli-responsive particulate system for delivery to deep lung tissue. Colloids Surf B Biointerfaces. 2016;146:19–30. doi: 10.1016/j.colsurfb.2016.05.031. [DOI] [PubMed] [Google Scholar]
- 41.Manni ML, Czajka CA, Oury TD, Vojtic I, Shaw S, Hedblom E, Hu J, Pins GD, Rolle MW, Dominko T. Extracellular matrix powder protects against bleomycin-induced pulmonary fibrosis. Tissue Eng Part A. 2011;17:2795–2804. doi: 10.1089/ten.TEA.2011.0024. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 42.Hammond JS, Gilbert TW, Howard D, Zaitoun A, Michalopoulos G, Shakesheff KM, Beckingham IJ, Badylak SF. Scaffolds containing growth factors and extracellular matrix induce hepatocyte proliferation and cell migration in normal and regenerating rat liver. J Hepatol. 2011;54:279–287. doi: 10.1016/j.jhep.2010.06.040. [DOI] [PubMed] [Google Scholar]
- 43.Almeida HV, Mulhall KJ, O’Brien FJ, Kelly DJ. Stem cells display a donor dependent response to escalating levels of growth factor release from extracellular matrix-derived scaffolds. J Tissue Eng Regen Med. 2016. Jul 12. doi: 10.1002/term.2199. [DOI] [PubMed] [Google Scholar]
- 44.Kim HJ, Lee S, Yun H-W, Yin XY, Kim SH, Choi BH, Kim YJ, Kim MS, Min B-H. In vivo degradation profile of porcine cartilage-derived extracellular matrix powder scaffolds using a non-invasive fluorescence imaging method. J Biomater Sci Polym Ed. 2016;27:177–190. doi: 10.1080/09205063.2015.1120262. [DOI] [PubMed] [Google Scholar]
- 45.Faulk DM, Londono R, Wolf MT, Yu F, Davidson JM, Guelcher SA, Duvall CL. ECM hydrogel coating mitigates the chronic inflammatory response to polypropylene mesh. Biomaterials. 2014;35:8585–8595. doi: 10.1016/j.biomaterials.2014.01.026. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 46.Wolf MT, Carruthers CA, Dearth CL, Ye J, Zhai H, Chen Y, Zhang L, Zeng Y. Polypropylene surgical mesh coated with extracellular matrix mitigates the host foreign body response. J Biomed Mater Res A. 2014;102:234–246. doi: 10.1002/jbm.a.34788. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 47.D’Amore A, Yoshizumi T, Luketich SK, Anand D, Garakani TM, Zhu L, Bocola M, Schwaneberg U, Böker A. Bi-layered polyurethane – extracellular matrix cardiac patch improves ischemic ventricular wall remodeling in a rat model. Biomaterials. 2016;107:1–14. doi: 10.1016/j.biomaterials.2016.08.033. [DOI] [PubMed] [Google Scholar]
- 48.Kim SH, Song JE, Lee D, Khang G. Development of poly(lactide-co-glycolide) scaffold-impregnated small intestinal submucosa with pores that stimulate extracellular matrix production in disc regeneration. J Tissue Eng Regen Med. 2014;8:279–290. doi: 10.1002/term.v8.4. [DOI] [PubMed] [Google Scholar]
- 49.Kang X, Zhao Z, Wu X, Shen Q, Wang Z, Kang Y, Xing Z, Zhang T. Experimental study on chitosan/allogeneic bone powder composite porous scaffold to repair bone defects in rats [Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi Zhongguo Xiufu Chongjian Waike Zazhi Chin]. J Reparative Reconstr Surg. 2016;30(3):298–302. [PubMed] [Google Scholar]
- 50.Angelozzi M, Miotto M, Penolazzi L, Mazzitelli S, Keane T, Badylak SF, Piva R, Nastruzzi C. Composite ECM-alginate microfibers produced by microfluidics as scaffolds with biomineralization potential. Mater Sci Eng C Mater Biol Appl. 2015;56:141–153. doi: 10.1016/j.msec.2015.06.004. [DOI] [PubMed] [Google Scholar]
- 51.Gao G, Cui X. Three-dimensional bioprinting in tissue engineering and regenerative medicine. Biotechnol Lett. 2016;38:203–211. doi: 10.1007/s10529-015-1975-1. [DOI] [PubMed] [Google Scholar]
- 52.Pati F, Song T-H, Rijal G, Jang J, Kim SW, Cho D-W. Ornamenting 3D printed scaffolds with cell-laid extracellular matrix for bone tissue regeneration. Biomaterials. 2015;37:230–241. doi: 10.1016/j.biomaterials.2014.10.012. [DOI] [PubMed] [Google Scholar]
- 53.Pati F, Jang J, Ha D-H, Won Kim S, Rhie J-W, Shim J-H, Kim D-H, Cho D-W. Printing three-dimensional tissue analogues with decellularized extracellular matrix bioink. Nat Commun. 2014;5:3935. doi: 10.1038/ncomms4935. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 54.Asadi-Eydivand M, Solati-Hashjin M, Shafiei SS, Mohammadi S, Hafezi M, Abu Osman NA, Burns JS. Structure, properties, and in vitro behavior of heat-treated calcium sulfate scaffolds fabricated by 3D printing. PLoS One. 2016;11:e0151216. doi: 10.1371/journal.pone.0151216. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 55.Jang J, Kim TG, Kim BS, Kim S-W, Kwon S-M, Cho D-W. Tailoring mechanical properties of decellularized extracellular matrix bioink by vitamin B2-induced photo-crosslinking. Acta Biomater. 2016;33:88–95. doi: 10.1016/j.actbio.2016.01.013. [DOI] [PubMed] [Google Scholar]
- 56.Chaudhary C, Garg T. Scaffolds: A novel carrier and potential wound healer. Crit Rev Ther Drug Carrier Syst. 2015;32:277–321. doi: 10.1615/CritRevTherDrugCarrierSyst.v32.i4. [DOI] [PubMed] [Google Scholar]
- 57.Turner NJ, Yates AJ Jr, Weber DJ, Qureshi IR, Stolz DB, Gilbert TW, Badylak SF. Xenogeneic extracellular matrix as an inductive scaffold for regeneration of a functioning musculotendinous junction. Tissue Eng Part A. 2010;16:3309–3317. doi: 10.1089/ten.tea.2010.0169. [DOI] [PubMed] [Google Scholar]
- 58.Shooter GK, Van Lonkhuyzen DR, Croll TI, Cao Y, Xie Y, Broadbent JA, Stupar D, Lynam EC, Upton Z. A pre-clinical functional assessment of an acellular scaffold intended for the treatment of hard-to-heal wounds. Int Wound J. 2015;12:160–168. doi: 10.1111/iwj.2015.12.issue-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 59.Shin YS, Choi JW, Park J-K, Kim YS, Yang SS, Min B-H, Kim C-H. Tissue-engineered tracheal reconstruction using mesenchymal stem cells seeded on a porcine cartilage powder scaffold. Ann Biomed Eng. 2015;43:1003–1013. doi: 10.1007/s10439-014-1126-1. [DOI] [PubMed] [Google Scholar]
- 60.Han N, Yabroudi MA, Stearns-Reider K, Helkowski W, Sicari BM, Rubin JP, Badylak SF, Boninger ML, Ambrosio F. Electrodiagnostic evaluation of individuals implanted with extracellular matrix for the treatment of volumetric muscle injury: case series. Phys Ther. 2016;96(4):540–549. doi: 10.2522/ptj.20150133. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 61.Liu Y-C-C, Chhabra N, Houser SM. Novel treatment of a septal ulceration using an extracellular matrix scaffold (septal ulceration treatment using ECM). Am J Otolaryngol. 2016;37:195–198. doi: 10.1016/j.amjoto.2016.01.013. [DOI] [PubMed] [Google Scholar]
- 62.Lev-Tov H, Li C-S, Dahle S, Evans D, Rauchhaus P, McSwiggan S, Page LF, Hogarth F. Cellular versus acellular matrix devices in treatment of diabetic foot ulcers: study protocol for a comparative efficacy randomized controlled trial. Trials. 2013;14:8. doi: 10.1186/1745-6215-14-59. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 63.Jia S, Zhang T, Xiong Z, Pan W, Liu J, Sun W, Nam J. In vivo evaluation of a novel oriented scaffold-BMSC construct for enhancing full-thickness articular cartilage repair in a rabbit model. PLoS One. 2015;10:e0145667. doi: 10.1371/journal.pone.0145667. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 64.Afaneh C, Abelson J, Schattner M, Janjigian YY, Ilson D, Yoon SS, Strong VE. Esophageal reinforcement with an extracellular scaffold during total gastrectomy for gastric cancer. Ann Surg Oncol. 2015;22:1252–1257. doi: 10.1245/s10434-014-4125-4. [DOI] [PubMed] [Google Scholar]
- 65.Riganti JM, Ciotola F, Amenabar A, Craiem D, Graf S, Badaloni A, Gilbert TW, Nieponice A. Urinary bladder matrix scaffolds strengthen esophageal hiatus repair. J Surg Res. 2016;204:344–350. doi: 10.1016/j.jss.2016.04.053. [DOI] [PubMed] [Google Scholar]
- 66.Abu Saleh WK, Al Jabbari O, Ramlawi B, Bruckner BA, Loebe M, Reardon MJ. Case report: cardiac tumor resection and repair with porcine xenograft. Methodist DeBakey Cardiovasc J. 2016;12:116–118. doi: 10.14797/mdcj-12-2-116. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 67.Abu Saleh WK, Al Jabbari O, Bruckner BA, Reardon MJ. Case report: A rare case of left atrial hemangioma: surgical resection and reconstruction. Methodist DeBakey Cardiovasc J. 2016;12:51–54. doi: 10.14797/mdcj-12-1-51. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 68.Abu Saleh WK, Al Jabbari O, Ramlawi B, Bruckner BA, Loebe M, Reardon MJ. Right atrial tumor resection and reconstruction with use of an acellular porcine bladder membrane. Tex Heart Inst J. 2016;43:175–177. doi: 10.14503/THIJ-15-5130. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 69.Rommer EA, Peric M, Wong A. Urinary bladder matrix for the treatment of recalcitrant nonhealing radiation wounds. Adv Skin Wound Care. 2013;26:450–455. doi: 10.1097/01.ASW.0000434617.57451.e6. [DOI] [PubMed] [Google Scholar]
- 70.Lecheminant J, Field C. Porcine urinary bladder matrix: a retrospective study and establishment of protocol. J Wound Care. 2012;21:476,478–480, 482. doi: 10.12968/jowc.2012.21.10.476. [DOI] [PubMed] [Google Scholar]
- 71.Ahmed T, Marçal H, Johnson S, Maiti S, Maiti TK. Coalescence of extracellular matrix (ECM) from porcine urinary bladder (UBM) with a laser-activated chitosan-based surgical adhesive. J Biomater Sci Polym Ed. 2012;23:1521–1538. doi: 10.1163/092050610X551943. [DOI] [PubMed] [Google Scholar]
- 72.Kruper GJ, Vandegriend ZP, Lin H-S, Zuliani GF. Salvage of failed local and regional flaps with porcine urinary bladder extracellular matrix aided tissue regeneration. Case Rep Otolaryngol. 2013;2013:917183. doi: 10.1155/2013/917183. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 73.Dorman RM, Bass KD. Novel use of porcine urinary bladder matrix for pediatric pilonidal wound care: preliminary experience. Pediatr Surg Int. 2016;32:997–1002. doi: 10.1007/s00383-016-3915-0. [DOI] [PubMed] [Google Scholar]
- 74.Frykberg RG, Cazzell SM, Arroyo-Rivera J, Tallis A, Reyzelman AM, Saba F, Warren L, Stouch BC, Gilbert TW. Evaluation of tissue engineering products for the management of neuropathic diabetic foot ulcers: an interim analysis. J Wound Care. 2016;25(Suppl 7):S18–25. doi: 10.12968/jowc.2016.25.7.S18. [DOI] [PubMed] [Google Scholar]
- 75.Iorio T, Blumberg D. Short-term results of treating primary and recurrent anal fistulas with a novel extracellular matrix derived from porcine urinary bladder. Am Surg. 2015;81:498–502(4):25–26. doi: 10.1093/jscr/rjt025. [DOI] [PubMed] [Google Scholar]
- 76.Sasse KC, Brandt J, Lim DC, Ackerman E. Accelerated healing of complex open pilonidal wounds using MatriStem extracellular matrix xenograft: nine cases. J Surg Case Rep. 2013;2013. (4):25–26. doi: 10.1093/jscr/rjt025. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 77.Brown BN, Chung WL, Almarza AJ, Pavlick MD, Reppas SN, Ochs MW, Russell AJ, Badylak SF. Inductive, scaffold-based, regenerative medicine approach to reconstruction of the temporomandibular joint disk. J Oral Maxillofac Surg. 2012;70:2656–2668. doi: 10.1016/j.joms.2011.12.030. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 78.Farnebo S, Woon CYL, Schmitt T, Joubert L-M, Kim M, Pham H, Chang J. Design and characterization of an injectable tendon hydrogel: a novel scaffold for guided tissue regeneration in the musculoskeletal system. Tissue Eng Part A. 2014;20:1550–1561. doi: 10.1089/ten.tea.2013.0207. [DOI] [PubMed] [Google Scholar]
- 79.Wu J, Ding Q, Dutta A, Wang Y, Huang Y-H, Weng H, Tang L, Hong Y. An injectable extracellular matrix derived hydrogel for meniscus repair and regeneration. Acta Biomater. 2015;16:49–59. doi: 10.1016/j.actbio.2015.01.027. [DOI] [PubMed] [Google Scholar]
- 80.Fu Y, Fan X, Tian C, Luo J, Zhang Y, Deng L, Qin T, Lv Q. Decellularization of porcine skeletal muscle extracellular matrix for the formulation of a matrix hydrogel: a preliminary study. J Cell Mol Med. 2016;20:740–749. doi: 10.1111/jcmm.2016.20.issue-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 81.Soucy KG, Smith EF, Monreal G, Rokosh G, Keller BB, Yuan F, Matheny RG, Fallon AM, Lewis BC, Sherwood LC, et al. Feasibility study of particulate extracellular matrix (P-ECM) and left ventricular assist device (HVAD) therapy in chronic ischemic heart failure bovine model. ASAIO J Am Soc Artif Intern Organs 1992. 2015;61(2):161–169. doi: 10.1097/MAT.0000000000000178. [DOI] [PubMed] [Google Scholar]
- 82.Slaughter MS, Soucy KG, Matheny RG, Lewis BC, Hennick MF, Choi Y, Monreal G, Sobieski MA, Giridharan GA, Koenig SC. Development of an extracellular matrix delivery system for effective intramyocardial injection in ischemic tissue. ASAIO J Am Soc Artif Intern Organs 1992. 2014;60(6):730–736. doi: 10.1097/MAT.0000000000000146. [DOI] [PubMed] [Google Scholar]
- 83.Massensini AR, Ghuman H, Saldin LT, Medberry CJ, Keane TJ, Nicholls FJ, Velankar SS, Badylak SF, Modo M. Concentration-dependent rheological properties of ECM hydrogel for intracerebral delivery to a stroke cavity. Acta Biomater. 2015;27:116–130. doi: 10.1016/j.actbio.2015.08.040. [DOI] [PMC free article] [PubMed] [Google Scholar]