In this work, we demonstrate a convenient, efficient and environmental benign strategy to achieve antimicrobial and antiadhesive purposes using a silver-zwitterion nanocomposite. Synthesis of the nanocomposite relies on loading zwitterionic polymer brushes with Ag+ precursor ions, followed by their in situ reduction to Ag nanoparticle by ultraviolet (UV) irradiation. Both poly(sulfobetaine methacrylate) (pSBMA) and poly (carboxybetaine methacrylate) (pCBMA) have been studied as matrices for the embedment of silver. Well-dispersed silver nanoparticles are embedded into pCBMA matrices. The obtained pCBMA-silver hybrid (CB-Ag) is capable of killing bacteria upon contact, and release dead bacteria under wet conditions. Results suggest the feasibility of using this nanocomposite system as a robust and reliable antimicrobial and antiadhesive platform for the prevention of microbial colonization. In addition, silver can be easily re-loaded into the surface by the UV method to regenerate its antimicrobial function when it is used up.