Polina Prokopovich,1,2 Ralph Leech,3 Claire J Carmalt,3 Ivan P Parkin,3 Stefano Perni41School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK; 2Institute of Medical Engineering and Medical Physics, School of Engineering, Cardiff University, Cardiff, UK; 3Materials Chemistry Research Centre, Department of Chemistry, University College London, London, UK; 4School of Chemical Engineering, University of Birmingham, Birmingham, UKAbstract: Post-operatory infections in orthopedic surgeries pose a significant risk. The common approach of using antibiotics, both parenterally or embedded in bone cement (when this is employed during surgery) faces the challenge of the rising population of pathogens exhibiting resistance properties against one or more of these compounds; therefore, novel approaches need to be developed. Silver nanoparticles appear to be an exciting prospect because of their antimicrobial activity and safety at the levels used in medical applications. In this paper, a novel type of silver nanoparticles capped with tiopronin is presented. Two ratios of reagents during synthesis were tested and the effect on the nanoparticles investigated through TEM, TGA, and UV-Vis spectroscopy. Once encapsulated in bone cement, only the nanoparticles with the highest amount of inorganic fraction conferred antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA) at concentrations as low as 0.1% w/w. No other characteristics of the bone cement, such as cytotoxicity or mechanical properties, were affected by the presence of the nanoparticles. Our work presents a new type of silver nanoparticles and demonstrates that they can be embedded in bone cement to prevent infections once the synthetic conditions are tailored for such applications.Keywords: bone cement, antimicrobial, silver nanoparticles, tiopronin, MRSA