Table II.
A list of different polymeric scaffolds implicated in tissue engineering applications with their respective modifications.
| Scaffold material | Modification description | Outcome |
|---|---|---|
| Collagen-GAG(69, 70) | Addition of GAG to collagen scaffolds, constant cooling rate during the freezing process prior to lyophilization | GAG effectively improves attachment, migration, and infiltration of cells throughout the porous scaffold; uniform porous structure and less variation in mean pore size |
| Collagen-GAG(71) | Collagen concentration (0.25 %, 0.5 %, and 1 %) and cross-link density (dehydrothermal crosslinking processes at 105 °C for 24 h and 150 °C for 48 h) | Significant improvement in the biological and mechanical properties of the scaffold with increased collagen amount (1 %) and crosslinking (at 150 °C for 48 h); enhanced pore size, permeability, compressive strength, cell number, and cell metabolic activity |
| Hyaluronic acid-based polymer(72–74) | Chemical modification through total esterification of carboxyl groups | Insoluble polymer with good stability against acidic hydrolysis; covalent binding of hydroxyl functional moieties; promotes cell adhesion, proliferation, ECM production, osteogenic differentiation, and mineralization |
| Hydroxyapatite/β-tricalcium phosphate ceramic implants(75) | MSCs loaded onto the porous carrier | Stronger bone formation superior to the carrier alone |
| Collagen-PGA(76, 77) | Collagen sponge mechanically reinforced by incorporation of PGA fiber (dehydrothermal cross-linking) | Enhancement in compression strength; sustained release of pDNA complex; significant attachment of fibroblasts, greater cell proliferation and infiltration; reduction in sponge shrinkage |
| Gelatin-PLGA(78) | PLGA microspheres loaded into gelatin scaffolds | Increased mechanical strength and flexibility; delivery of multiple genes with distinct release kinetics |
| PLA, PGA, PLGA(79) | Type of polymer, molecular weight, intrinsic viscosity | High porosity with low molecular weight, PLGA with low intrinsic viscosity; superior mechanical properties with higher lactic acid content |
| PLGA(80) | Partial fusion of NaCl porogen in the solvent casting-particulate leaching process | Scaffolds with enhanced pore interconnectivity and compressive modulus |
| PLLA(81) | Scaffold surface modification using gelatin spheres as porogen | Higher compressive modulus; significant improvement in initial cell adhesion and proliferation, cell spreading and matrix secretion |
| Hyaluronan(82) | Modification with gelatin using disulfide crosslinking | Hyaluronan-gelatin sponge promoted cell attachment, growth, and spreading |
| PLGA(83) | Coating PLGA microspheres with polydopamine | Increased incorporation and slowed release of pDNA from the scaffold |
| Collagen(84) | Calcium-phosphate coating for collagen scaffolds | Improved mechanical properties (higher compressive modulus/stiffness) |
| Collagen(85, 86) | Nano-hydroxyapatite inclusion in the scaffold | Enhanced cell function and osteointegration; significantly increased scaffold stiffness and pore interconnectivity |
| PCL(87) | Coupling resveratrol through a hydrolysable covalent bond with the carboxylic acid groups on PCL surface grafted with acrylic acid | Significant increase in osteogenesis |
| Alginate(88) | Mixing octacalcium phosphate (OCP) with alginate solution | Increased elastic modulus and pore size with increasing OCP concentration |
| Collagen(58) | Specific binding of biotinylated PEI-pDNA complexes to avidin-modified collagen | Enhanced transfection efficiency by immobilizing complexes in the matrix through biotin/avidin bond; inhibits aggregation of complexes; higher loading efficiency and bioavailability of complexes |