Table 3.
Summary of effects of sterilization methods on biodegradable scaffolds.
| Category | Technique | Condition | Scaffold | Effect of sterilization of scaffold | Result of sterilization method | Reference |
|---|---|---|---|---|---|---|
| Heat | Heat treatment | Steam treatment with air removal, 129°C | PLA | Increase in mechanical strength; decrease in molecular weight | Not tested | Rozema et al.14 |
| Dry heat treatment, 135°C, vacuum atmosphere | Lactide copolymers | Increase in molecular weight; decrease in bending strength | Not tested | Gogolewski and Mainil-Varlet15 | ||
| Irradiation | Gamma | Dose rate: 2.11 kGy/h | Copolymers of LLA, CL, and DXO | Decrease in molecular weight; random chain scission; cross-linking | Not tested | Plikk et al.16 |
| Dosage: 25 kGy, vacuum atmosphere, 140°C, 12 h | Hydroxyapatite–collagen composite scaffolds | Decrease in compressive mechanical strength; increase in degradation rate | Not tested | Yunoki et al.17 | ||
| Dosage: 30.8 kGy | PCL | Increase in the yield point and the maximum stress; alteration in mechanical structure | Not tested | Cottam et al.18 | ||
| Dosage: 25 kGy | Poly[(butylene terephthalate)-co-poly(butylenesuccinate)-block-poly(ethylene glycol)] | Decrease in elongation at break, tensile strength, and molecular weight | Slow cell growth | Wang et al.19 | ||
| Dosage: 39 kGy | PLLA | Decrease in molecular weight and mechanical strength; increase in degradation rate | Not tested | Hooper et al.20 | ||
| Dosage: 10–50 kGy, atmosphere | PCL-hydroxyapatite composites | Chain scission | Not tested | Di Foggia et al.21 | ||
| Dosage: 3 kGy | PLGA | Decrease in tensile strength | Remained sterile for >3 months | Selim et al.22 | ||
| E-beam | Dosage: 25–150 kGy, room temperature | PCL | Cross-linking, chain scission; increase in the modulus of elasticity | Not tested | Olah et al.23 | |
| Dosage: 26.6 ± 2.0 kGy | Poly(l,dl-lactide) (PLDLLA) | Decrease in inherent viscosity; faster mechanical degradation | Not tested | Smit et al.24 | ||
| Dosage: 25–75 kGy, 2.5°C | Copolymers of LLA, CL, and DXO | Decrease in molecular weight; random chain scission | Not tested | Plikk et al.16 | ||
| Dosage: 25 kGy, an inert atmosphere | Poly(LLA-co-DXO) | Decrease in molecular weight | Not tested | Dånmark et al.25 | ||
| UV | 5–24 h | Me.PEG-PLA | Increase in degradation rate; chain depletion; change to biochemical properties | Not tested | Fischbach et al.4 | |
| 2 h | Me.PEG-PLA | NA | Not tested | Fischbach et al.4 | ||
| 12 h, 245–365 nm | PLA | Decrease in molecular weight; increase in degradation rate | Effective in inactivating microorganisms | Janorkar et al.26 | ||
| 30 min–8 h, 254 nm | PLGA and P(LLA-CL) | Decrease in molecular weight, tensile strength; increase in degradation rate; morphological change | Not tested | Dong et al.27 | ||
| 0.5–2 h, 254 nm | PLGA | Decrease in molecular weight | Generated sterile scaffolds | Braghirolli et al.12 | ||
| Plasma | Plasma | Inert argon gas, 2–10 min for 33 W; 2–40 min for 100 W | PLGA | Affect chemical structure; change degradation behavior; increase in molecular weight | Not tested | Holy et al.28 |
| Oxygen, carbon dioxide, ammonia plasmas | Polyurethane | Decrease in molecular weight; increase in mechanical property | Not effective | Gorna and Gogolewski29 | ||
| Hydrogen peroxide | Polyurethane | Decrease in molecular weight and tensile strength; increase in degradation rate | Activation of microorganism | Gorna and Gogolewski29 | ||
| Hydrogen peroxide, 1 h and 39 min, 43°C | PLLA biomaterial | Physical aging; increase in melting and glass transition temperatures, crystallinity, and brittleness | Not tested | Peniston and Choi30 | ||
| Hydrogen peroxide, 55 min, 45°C–55°C | Polyurethane | Increase in degradation rate | Not tested | Bertoldi et al.31 | ||
| Chemical treatment | EtO | Poly(DTE carbonate) | Decrease in yield strength and stiffness | Not tested | Hooper et al.20 | |
| Poly(DTO carbonate) | Increase in degradation rate; decrease in molecular weight | Not tested | Hooper et al.20 | |||
| 100% ethylene oxide atmosphere, 57°C, 2 h | PLGA | Shrinkage in dimensions; decrease in molecular weight; affects brittleness and stiffness | Not tested | Holy et al.28 | ||
| 18–96 h, 32°C–45°C, 45%–70% humidity | PLDLLA | Delays degradation | Not tested | Smit et al.24 | ||
| Peracetic acid | 2 h, room temperature | Collagen fibers | Affect structural integrity and bioactive properties | Not tested | Hodde et al.32 | |
| 0.1% PAA, 15 min–24 h | PLGA | Increase in surface roughness and pore size; surface cracking | Not tested | Shearer et al.33 | ||
| 0.1% PAA, 3 h, room temperature | PLGA | Decrease in tensile strength and fiber diameter | Remained sterile for >3 months | Selim et al.22 | ||
| Ethanol | 70% Ethanol | Chitosan membranes | Increase in tensile strength | Not tested | Marreco et al.34 | |
| 70% Ethanol, 15 min–24 h | PLGA | Structural change; decrease in breaking stress and porosity; increase in fragility and surface wrinkling | Not tested | Shearer et al.33 | ||
| 70% Ethanol, 5 min, 4°C | PLGA | Decrease in tensile strength and fiber diameter | Became infected within 2–14 days | Selim et al.22 | ||
| 70% Ethanol, 0.5–2 h | PLGA | Changes in the morphology and scaffold dimensions; hampering cellular adhesion | Generated sterile scaffolds | Braghirolli et al.12 | ||
| Iodine | 0.1% Iodine solution, 1–12 min | Allografts (pericardial tissue) | Complete inactivation of a wide variety of bacterial organisms | Moore et al.11 | ||
| Novel techniques | sCO2 | 205 bar, 0.6–4 h, 25°C–40°C | PLGA and PLA | Complete inactivation of a wide variety of bacterial organisms | Dillow et al.35 | |
| 27.6 MPa, 60 min, 40°C | Hydrogel, poly(acrylic acid-co-acrylamide) potassium salt | Effective in inactivating microorganisms | Jimenez et al.36 | |||
| 3.3% water, 0.1% hydrogen peroxide, 80 atm, 30 min, 50°C | NA | 6-log inactivation of Bacillus pumilus | Checinska et al.37 | |||
| 0.25% water, 0.15% hydrogen peroxide, and 0.5% acetic anhydride | Collagen-based scaffolds | Increase in compressive modulus | Vegetative bacteria, fungi, and bacteriophages; bacteria spores were inactivated | Bernhardt et al.38 | ||
| Antibiotics | Combined with UV irradiation | Polyphosphate; polyphosphonate | NA | Not tested | Richards et al.39 | |
| 1% Antibiotic antimycotic solution, 6–31 h, 4°C | PLGA | Increase in roughness | Not tested | Shearer et al.33 | ||
| 1% Antibiotic solution, 1–2 h | PLGA | Changes in the morphology and scaffold dimensions | Generated sterile scaffolds | Braghirolli et al.12 | ||
| Freeze-drying | Combined with gas plasma, 24–72 h | Collagen sponges | NA | Effective in inactivating microorganisms | Markowicz et al.13 |
PLA: poly(lactic acid); LLA: l-lactic acid; CL: ε-caprolactone; DXO: 1,5-dioxepane-2-one; PCL: poly(ε-caprolactone); PLLA: poly(l-lactic acid); PLGA: poly(lactide-co-glycolide); P(LLA-CL): poly(l-lactide-co-ε-caprolactone); UV: ultraviolet; Me.PEG-PLA: poly(d,l-lactic acid)-poly(ethylene glycol)-monomethyl ether diblock copolymer; DTE: desaminotyrosyl-tyrosine ethyl ester; DTO: desaminotyrosyl-tyrosine octyl ester; PAA: peracetic acid; NA: not applicable.