Characterisation and cooperative antimicrobial properties of chitosan/nano-ZnO composite nanofibrous membranes

Chitosan was combined with nano-ZnO to increase its antimicrobial activity, using polyvinyl alcohol as a support, and then were electronspun to form composite nanofibres. Through SEM, EDX and XRD observations, chitosan was seen to be able to incorporate nano-ZnO in the composite nanofibres. Escherichia coli, expressing recombinant enhanced green fluorescent protein, and Candida albicans were used to test the antimicrobial efficacy of the newly synthesised chitosan/nano-ZnO antimicrobial composite. The CdTe quantum dots were used to rapidly detect the residual changes of C. albicans and determine the end point of using antimicrobial agents. Minimal minimum inhibitory concentration (MIC), post-antibiotic effect and continuous agent effect of the composite were determined. The MIC of chitosan/nano-ZnO against C. albicans was 160 μg/ml, close to the concentration of the treated composite with the lowest fluorescence intensity. The cell damage was observed by SEM, which indicated that nano-ZnO in the nanofibrous membranes played a cooperative role in the antimicrobial process of chitosan.