In vitro properties of crosslinked, reconstituted collagen sheets

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Dermatology

Background:

• Collagen sheets are being developed as potential burn coverings.
• Crosslinking methods (UV light, chromium, cysteine) and surface agents were investigated.
• Cytotoxicity is a critical factor for biomaterials used in wound healing.

Purpose of the Study:

• To evaluate the cytotoxicity of modified collagen sheets for burn wound applications.
• To assess the impact of crosslinking and surface agents on human keratinocyte and fibroblast proliferation.
• To determine chromium leaching levels in crosslinked collagen sheets.

Main Methods:

• Preparation of 100-micron-thick collagen sheets crosslinked with UV light, chromium, or cysteine.
• Exposure of collagen sheets to surface agents: hydroxyproline, fibronectin, or soluble basement membrane matrix.
• Cytotoxicity testing using human keratinocytes and fibroblasts.
• Quantification of cell proliferation via 3H-thymidine incorporation and autoradiography.
• Determination of chromium leaching using pharmacopeial standards.

Main Results:

• A universal decrease in keratinocyte proliferation was observed after 1-day exposure to all collagen sheets, which lessened by day 5.
• Fibroblast proliferation initially increased after 1-day exposure, particularly with UV-crosslinked collagen, with a similar decrease by day 5.
• Autoradiography revealed minimal significant variations in cell morphology.
• Chromium leaching from crosslinked sheets remained below 30% of British and American Pharmacopeia allowable limits.

Conclusions:

• Modified collagen sheets exhibit differential cytotoxicity towards keratinocytes and fibroblasts.
• UV-crosslinked collagen sheets show potential for burn covering applications with acceptable chromium levels.
• Further research is needed to optimize collagen sheet properties for enhanced wound healing and adherence.