Methacrylate-ended　polypeptides/polypeptoids　were　successfully　synthesized　via　ring-opening　polymerization　(ROP)　of　N-carboxyanhydrides　(NCA).　These　oligomers　were　further　initiated　under　ultraviolet　(UV)　irradiation　by　a　polydopamine　(pDA)　layer　which　is　attachable　to　the　surface　of　virtually　all　materials　to　generate　a　polymer　brush　coating.　This　brush-like　polymer　coating　comprising　cationic　antimicrobial　polypeptides　(MePpep)　and　antifouling　polysarcosine　(MePsar)　exhibited　effective　antimicrobial　activity　against　four　pathogens　(Staphylococcus　aureus,　Escherichia　coli,　Pseudomonas　aeruginosa,　and　Candida　albicans),　as　well　as　antifouling　activity　in　the　resistance　to　protein　and　platelet　adhesion,　and　thus　prevented　biofilm　formation　for　up　to　7　days.　An　in　vitro　cytotoxicity　study　showed　that　this　coating　is　biocompatible　with　mouse　fibroblast　(L929)　cells.　More　importantly,　this　coating　exhibited　significant　anti-infectivity　in　vivo.　This　dual-functional　polymer　brush　coating　can　be　immobilized　on　the　surface　of　multiple　categories　of　materials　through　the　mussel-inspired　pDA　coating,　and　thus　should　be　widely　applicable　for　combating　infection　in　many　classes　of　bio-medical　materials.