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Analysis of sterilization protocols for peptide-modified hydrogels.
Nathaniel Huebsch1, Michele Gilbert, Kevin E Healy
1Department of Bioengineering, University of California at Berkeley, 370 Hearst Memorial Mining Building, 94720-1762, USA.
Summary
Ultraviolet (UV) irradiation failed to sterilize N-isopropylacrylamide hydrogels containing biomimetic peptides, allowing bacterial growth and degrading peptides. Ethanol disinfection proved more effective for these bioactive materials.
Area of Science:
- Biomaterials science
- Sterilization techniques
- Peptide chemistry
Background:
- Implanted biomaterials require effective sterilization to prevent infection.
- Ethanol disinfection is a common method, but its efficacy for novel peptide-modified hydrogels is questioned.
- Ultraviolet C (UVC) irradiation offers a potentially low-cost, scalable alternative for laboratory sterilization.
Purpose of the Study:
- To evaluate UVC irradiation as a terminal sterilization method for N-isopropylacrylamide-based hydrogels functionalized with biomimetic peptides.
- To compare the efficacy of UVC irradiation with ethanol disinfection in preventing bacterial growth within hydrogels.
- To assess the impact of UVC irradiation on the structural integrity of incorporated peptides.
Main Methods:
- N-isopropylacrylamide hydrogels containing Arg-Gly-Arg (RGD) peptides were prepared.
- Hydrogels were subjected to UVC irradiation (400 μW/cm² for up to 15 hours) or ethanol disinfection.
- Sterility was assessed by challenging hydrogels with Escherichia coli and monitoring bacterial growth.
- Peptide integrity was evaluated after UVC exposure.
Main Results:
- UVC irradiation at the tested parameters did not prevent Escherichia coli growth within the hydrogels.
- Ethanol disinfection successfully inhibited bacterial growth for 120 hours.
- UVC irradiation led to progressive degradation of the RGD-containing peptides.
- The study system is a preliminary evaluation tool, not compliant with cGMP for medical device sterility.
Conclusions:
- UVC irradiation is unsuitable as a terminal sterilization method for peptide-modified hydrogels due to its inefficacy against bacteria and detrimental effect on peptide structure.
- Ethanol treatment remains the preferred disinfection method for bioactive materials containing UV-sensitive peptides or groups.
- Further research into sterilization methods that preserve biomolecular integrity is warranted for advanced biomaterials.