Improved microbial growth inhibition activity of bio-surfactant induced Ag–TiO 2 core shell nanoparticles

•TiO2 nanoparticles were synthesized by hydrolysis process and Ag nanoparticles were prepared by using hydrazine reduction method.•Ag–TiO2 core shell nanoparticles were synthesized by reverse micelle method.•Coatings of TiO2 shell leads to decrease the usage of silver particles and also it reduces the release of silver ions from the matrix.•Optimum ratio of TiO2 particles: Ag atoms are needed for better antibacterial activity.•Sodium alginate (Bio-copolymer) induced core shell nanoparticles results 100% cell growth inhibition toward Staphylococcus aureus.