Conventional methods of antibacterial characterization assume homogeneity in the effects of inhibitory agents on a bacterial population. Current research aims to uncover the heterogeneity of these effects by utilizing single-cell methods of characterization, but many of these methods utilize microfluidic-based devices which limit the types of agents that can be studied. Specifically, these devices are incapable of studying the inhibitory activity of agents such as polymeric matrices, which have been used extensively in the development of wet wound management materials. These wet wound management materials have been shown to proliferate skin cell growth and increase oxygen permeation, resulting in faster rates of healing. Furthermore, these materials are frequently modified with metal nanoparticles (MNPs) to enhance antibacterial properties and mitigate bacterial growth while preserving the biomimicry required for skin cell regeneration. While the mechanism of cell death due to colloidal MNPs has been extensively investigated, minimal attention has been given to the mechanisms of cell death attributed to MNP-functionalized polymeric substrates. To further uncover these mechanisms, this research utilizes epi-fluorescent optical tweezers to investigate their antibacterial properties. Specifically, a single <i>E. coli</i> cell is optically trapped and non-covalently docked to a functionalized polymer matrix, after which cell lysis kinetics are monitored in real-time via fluorescent cell viability indicators. Inhibitory effects of Ag NP-incorporated matrices showed increased antibacterial activity related to the Ag<sup>0</sup> concentration and size of the colloidal NPs. Additionally, non-covalent functionalization of Au NPs with select antibiotics has shown increased antibacterial activity when compared to trisodium citrate-capped Au NPs, demonstrating the tunability and effective delivery capabilities of the nanocomposite matrix.

Single-cell optical trapping technique for real-time antibacterial characterization of novel wound management materials

2019 Spring National Meeting

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