No abstract

Polypropylene (PP) coated by a non-leachable biocide was prepared by chemically attaching poly(quaternary ammonium) (PQA) to the surface of PP. The well-defined poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA), a precursor of PQA, was grown from the surface of PP via atom transfer radical polymerization (ATRP). The tertiary ammine groups in PDMAEMA were consequently converted to QA in the presence of ethyl bromide. Successful surface modification was confirmed by ATR-FTIR, contact angle measurement, and an antibacterial activity test against Escherichia coli (E. coli). The biocidal activity of the resultant surfaces depends on the amount of the grafted polymers (the number of available quaternary ammonium units). With the same grafting density, the surface grafted with relatively high MW polymers (M(n) > 10,000 g/mol) showed almost 100% killing efficiency (killing all of the input E. coli (2.9 x 10(5)) in the shaking test), whereas a low biocidal activity (85%) was observed for the surface grafted with shorter PQA chains (M(n) = 1,500 g/mol).

We have developed a novel technique to synthesize near-uniform protein-polymer conjugates by initiating atom transfer radical polymerization of monomethoxy poly(ethylene glycol)-methacrylate from 2-bromoisobutyramide derivatives of chymotrypsin (a protein-initiator). Polymerization initiated from the monosubstituted protein-initiator resulted in the conjugate containing a single, near-monodisperse polymer chain per protein molecule with polydispersity index 1.05. Increasing the number of conjugated 2-bromoisobutyramide initiators per molecule of protein increased the molecular weights and polydispersity indices of the final protein-polymer conjugates. The generic nature of this technique was demonstrated by initiating polymerization of nonionic, cationic, and anionic monomers from the protein-initiator. Protein-polymer conjugates synthesized by this novel technique retained 50-86% of the original enzyme activity. The technique described herein should be useful in synthesizing well-defined protein-polymer conjugates exhibiting a wide range of physical and chemical properties.