Background: Peripheral nerve injuries present a major challenge due to limited functional and sensory recovery with current treatments. Human amniotic and umbilical cord membranes show promise in tissue regeneration but are limited by the quantity and variety of growth factors they release. This study evaluates the efficiency of umbilical cord and placental membranes as biological scaffolds for lysozyme delivery. The assessment includes investigating the binding capacity of double-walled microspheres (DWMS) loaded with lysozyme to the membranes and characterizing the subsequent lysozyme release kinetics.

Methods: Lysozyme, chosen for its similar properties to glial-derived neurotrophic factor (GDNF), was encapsulated in biodegradable poly lactic-co-glycolic acid (PLGA)/poly lactic acid (PLA) microspheres using a water-oil-water emulsion solvent evaporation technique. The binding capacity and release kinetics of lysozyme from DWMS bound to cryopreserved and lyophilized umbilical cord and placental membranes were assessed over 1, 6, and 24 hours, using the Bicinchoninic Acid assay.

Results: Our findings demonstrated that lysozyme-loaded DWMS bound similarly to both cryopreserved and lyophilized umbilical cord membranes. However, placental membranes soaked for 1 and 24 hours exhibited significantly higher lysozyme release (p<0.05) compared to non-loaded membranes. Notably, placental membranes soaked for 24 hours released 1.57 times more lysozyme than those soaked for 1 hour at the 72-hour mark. Furthermore, lysozyme release from both cryopreserved and lyophilized umbilical cord membranes was significantly greater after 6 and 24 hours of DWMS treatment compared to placental membranes (p<0.05). Cryopreserved umbilical cord membranes specifically showed a greater release than lyophilized membranes when assessed at these time points (p<0.05).

Conclusion: Placental membranes demonstrated superior efficacy as scaffolds for lysozyme-loaded DWMS delivery, particularly with longer incubation periods. Cryopreserved umbilical cord membranes were more effective than lyophilized ones, suggesting that preservation methods impact therapeutic potential. These findings highlight a novel approach for enhancing peripheral nerve regeneration through improved drug delivery systems.