Perhydrolase-nanotube-paint sporicidal composites stabilized by intramolecular crosslinking

We have developed a strategy to preserve the activity and operational stability of a large multi-subunit enzyme immobilized onto carbon nanotubes and incorporated into latex paint. Our strategy involved the intramolecular crosslinking of perhydrolase S54V (AcT, a homo-octamer) and the subsequent immobilization of the crosslinked AcT onto single-walled carbon nanotubes (SWNTs). We employed aldehyde dextran – a bulky polymeric aldehyde obtained by oxidation of dextran with sodium metaperiodate – as a crosslinking reagent. The activity of AcT crosslinked with aldehyde dextran and covalently attached to SWNTs (AcT-dex-SWNTs) was ∼40% of that of native AcT and more than two-fold higher than that of enzyme immobilized directly, i.e., without crosslinking. This relatively high retention of AcT activity was consistent with the nearly complete retention of the enzymeʹs secondary structure upon attachment to the nanoscale support. Further incorporation of the AcT-dex-SWNTs conjugates into a latex-based paint led to active composites that were used to decontaminate Bacillus spores.