(756a) Bactericidal Hydrogels Via Photointiated Thiol-Acrylate Interfacial Polymerization

Rapid and precise pathogen deactivation is of crucial importance in the medical, food, and biodefense industries.  Antimicrobial peptides (AMPs) are a tremendous natural resource for developing decontamination surfaces owing to their innate broad spectrum activity.  Thus far, AMP immobilization has been predominantly restricted to inorganic solid supports such as gold or glass despite recognized limitations, such as nonspecific biomolecular adsorption, labor-intensive peptide immobilization, and singular peptide orientation upon immobilization.  Alternatively, the exchange of gold or glass for poly(ethylene glycol) (PEG) hydrogel supports would eliminate nonspecific binding in addition to broadening the scope of immobilization techniques and end applications.  Therefore, the primary objective of this work was to establish a novel platform for the immobilization of Cecropin A (CPA) to the surfaces of PEG hydrogels via photoinitiated thiol-acrylate interfacial polymerizations.  Using a 1:1 stoichiometric ratio of thiol:acrylate in the interfacial monomer formulation allowed coatings to be formed under ambient conditions without complete thiol conversion.  The unreacted thiol was then conjugated with maleimide moieties within CPA sequences over a range of surface densities and configurations.  Surface density was controlled by the weight fraction of PEG thiol and PEG acrylate in the interfacial monomer solution, while CPA surface configuration was altered by the type of PEG thiol that was incorporated.  Specifically, the molecular weight of 4-arm PEG thiol (5 kDa, 10 kDa, and 20 kDa) was varied to investigate the influence of linker length on antibacterial activity, and the degree of thiol functionality (bifunctional 5 kDa, 4-arm 10 kDa, and 8-arm 20 kDa) was varied to control the arrangement of CPA on the surface.  Propidium idodide/Syto 9 staining was used to quantify the activity of CPA against E. coli K235.