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Abstract The present research work describes a novel method for green synthesis of silver nanoparticles using purple heart plant leaves extract, which is recognized as frequently found in households as an ornamental plant. The aqueous methanolic extract of purple heart plant leaves was prepared and employed in the synthesis of stable silver nanoparticles via biological reduction method. The purple heart plant leaves extract-mediated synthesized silver nanoparticles were systematically optimized using Box-Behnken design considering the effect of various independent variables (factors) like concentration of AgNO 3 , temperature and volume of purple heart plant leaves extract solution on the responses like particle size and polydispersity index of synthesized silver nanoparticles were optimized. Mathematical modelling was performed using quadratic polynomial model and response surface analysis was done to understand the factor-response relationship. The synthesized silver nanoparticles at optimum condition were found to be of spherical in shape under TEM with particle size of 98 nm and polydispersity index of 0.15. Optimized silver nanoparticles were further characterized through UV-VIS spectrophotometry, FTIR spectroscopy and TEM imaging studies. Also, the silver nanoparticles were evaluated for antibacterial activity on E. coli and S. aureus. In a nutshell, the studies construed successful synthesis of silver nanoparticles along with thorough understanding of the associated factors influencing their quality characteristics and significantly improved antibacterial activity as beneficial effect. Graphical abstract Unlabelled Image Highlights • Silver nanoparticles were synthesized using purple heart plant leaves extract. • These synthesized silver nanoparticles were optimized by Box-Behnken design. • Particle size and polydispersity index were investigated as response variables. • Optimized silver nanoparticles showed 98 nm particle size and 0.15 polydispersity index. • Optimized silver nanoparticles showed antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) alloys present great potential for the development of orthopedic implants, whereas, their high degradation rate and poor antibacterial performance have restricted orthopedic applications. In this work, PLLA/GO-AgNP (poly-L-lactic acid/graphene oxide- silver nanoparticle) with different concentration of GO-AgNPs were deposited on Mg alloy via electrospinning method for enhancement of corrosion resistance and antibacterial performance. The result revealed that incorporation of GO into PLLA fibrous considerably slowed down the degradation rate of Mg alloy substrate and reduced the H 2 release rate from the substrate. Also, co-incorporation of GO and AgNPs into PLLA fibrous resulted in substantial escalate in compressive strength after immersion in simulated body fluid (SBF). Antibacterial activity test exhibited that Mg alloy and neat PLLA fibrous presented minimal inhibition area toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In contrast, using PLLA/GO-AgNPs fibrous improved antibacterial performance against both bacteria. Cytocompatibility results indicated that PLLA/GO-AgNPs fibrous with a low amount of GO-AgNPs enhanced cell proliferation and growth while high co-incorporation of GO-AgNPs showed a negative effect on cell proliferation. Taken together, PLLA/1GO-AgNPs fibrous coating shows suitable corrosion resistance, cytocompatibility, and antibacterial function for use in orthopedic applications. Unlabelled Image • Multifunctional PLLA/GO-Ag fibrous layers were prepared on Mg-Ca-Zn alloy using the electrospinning method. • PLLA/GO-Ag fibrous coating results in superior corrosion resistance and cytocompatibility than uncoated Mg alloy. • Antibacterial performance of fibrous layers increases with increasing GO-Ag concentration. • Corrosion and antibacterial mechanism of the fibrous-coated Mg-Ca-Zn alloy is proposed. [ABSTRACT FROM AUTHOR]