According to the Web of Science, during the past five years, there were over 5000 new publications with more than 34 thousand citations concerning the antibacterial property of silver nanoparticles (Ag NPs). However, the translations of Ag NPs into drugs and medical devices provoked serious concerns about their cytotoxicity resulted via cellular uptake . Enhancing the intracellular stability of Ag NPs was an effective paradigm to improve their compatibility, whereas it could abolish the bactericidal activity of the particles . Here, based on our previous findings [3-6], we presented that size-tunable silver nanoparticles (Ag NPs) can be in situ synthesized and immobilized on titanium oxide coatings (TOC) by manipulating the atomic-scale heating effect in silver plasma immersion ion implantation (Ag PIII). The titanium oxide supported Ag NPs possess electron storage capability that gives rise to both controlled antimicrobial activity and excellent compatibility with mammalian cells. The key points to be discussed are: (1) why we should control the antimicrobial actions of silver nanoparticles; (2) how we make the particles act differently to bacterial and mammalian cells. These themes are important and valuable to the biomaterials and biomedical engineering community, and they have not been fully covered in those published articles so far.
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