Cryopreservation of human amniotic membrane for ocular surface reconstruction: a comparison between protocols

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cryobiology

Background:

• Human amniotic membrane is a valuable biological material for regenerative medicine.
• Established cryopreservation protocols using dimethyl sulfoxide (DMSO) at -180°C are effective but complex and potentially toxic.
• Safer and simpler preservation methods are needed to enhance clinical applicability.

Purpose of the Study:

• To evaluate novel preservation conditions for human amniotic membrane.
• To compare the adhesive and structural integrity of tissues preserved with newer methods against a standard protocol.
• To assess the feasibility of using -80°C storage with alternative media or dry conditions.

Main Methods:

• Human amniotic membrane samples from three donors were preserved under five conditions: DMSO at -180°C, DMSO at -80°C, dextran-based medium at -180°C, dextran-based medium at -80°C, and dry freezing at -80°C.
• Samples were stored for four months.
• Adhesive properties and structural integrity (stromal layer, basement membrane) were analyzed post-storage.

Main Results:

• No statistically significant differences in adhesive or structural properties were observed between the newer preservation protocols and the established DMSO protocol.
• The stromal layer maintained its adhesiveness across all tested conditions.
• The overall tissue structure and basement membrane integrity remained unaltered by any preservation method.

Conclusions:

• Cryopreservation of human amniotic membrane at -80°C, using dextran-based or dry conditions, is a viable alternative to traditional liquid nitrogen storage.
• These simplified protocols reduce manipulation, enhance safety by avoiding DMSO toxicity, and offer cost-effectiveness.
• The findings support the transition to more accessible and safer preservation techniques for clinical use.