Antibiotic incorporation in jet-sprayed nanofibrillar biodegradable scaffolds for wound healing

In view of preparing antibiotic-loaded structures that can be used as dressing to prevent or contain wound infections, this study evaluates biodegradable nanofibrillar matrices obtained by jet-spraying and containing ciprofloxacin (CIF). The matrices were prepared from different blends of poly-(ε-caprolactone) (PCL) and poly-d,l-(lactic acid) (PDLLA) in view of controlling mechanical properties, biodegradation and antibiotic release rate. The effect of CIF incorporation was assessed in regard of matrices fiber diameter, mechanical properties and degradation while antibiotic release from the polymer blends of different PCL/PDLLA ratios was measured in buffers of different pH to better mimic the wound context. Finally, antibiotic activity of the nanofibrillar matrices and their ability to be colonized by skin cells were evaluated. Non-woven nanofibrillar matrices could be obtained from various polymer blends by jet-spraying and CIF crystals incorporation was easily obtained. The crystals were dispersed in the fibers, without complete embedding. Antibiotic incorporation resulted in a slight increase of fiber diameter and did not modified the mechanical properties of the various matrices composed of different polymer blends. Unlike fiber diameter, degradation and mechanical properties of the fibrillar matrices, CIF release profiles were not controlled by the polymer blend ratios. However, sustained release was observed over more than 23days. Due to the antibiotic pH-dependent solubility, burst release was more prominent in acidic conditions, which mimic the pH of undamaged skin. Finally the incorporated antibiotic was efficient in inhibiting bacterial growth of E. coli and B. subtilis whereas human fibroblasts were able to colonize the CIF-loaded matrices.