Optimization of reaction conditions to fabricate Ocimum sanctum synthesized silver nanoparticles and its application to nano-gel systems for burn wounds.

Abstract The present study deals with sequential optimization strategy based on Box-Behnken method to optimize the process variables for efficient production of Ocimum sanctum synthesized silver nanoparticles using biological synthesis. Four substantial factors influencing the dependent variables viz size, zeta potential, Polydispersity index (PDI) and yield were identified as silver nitrate concentration, temperature, amount of plant extract and stirring speed as independent variables. The contribution of the studied factors in monitoring dependent variables was evaluated via analysis of variance. The validity of the model developed was verified, and the statistical analysis showed that the optimal operational conditions were AgNO 3 concentration 5.29 mM, temperature 60 °C, agitation speed of 500 rpm and plant extract 2.24% (w/v) which primes to form silver nanoparticles of smallest size 83.41 nm and 0.24 with maximum zeta potential of -20.20mV and Yield of 18.62. In addition, the optimized AgNPs were characterized using DLS, TEM, FE-SEM and UV‐vis analysis. The topical formulation was prepared by incorporation of optimized AgNPs into the carbopol gel base. Further, the gel was evaluated in vivo using the rat model of skin wound healing. The measurement of the wound areas was performed on 2nd, 4th, 6th, 8th, 10th, 12th and 14th days and the percentage of wound closures were calculated accordingly. By the 14th day, silver nanoparticle gel showed 96.20% wound healing activity compared with that of the standard as well as control base. The antibacterial inhibitory efficiency of prepared nano gel was found similar to the commercial product against the Staphylococcus aureus , E. coli and Pseudomonas aeruginosa. Graphical abstract Unlabelled Image Highlights • Efficient method to synthesize AgNPs using aqueous O. sanctum leaf extract that acted both as reducing and capping agent. • Box-Behnken method to optimize the process parameters for silver nanoparticles production. • Development of topical dosage gel and evaluated in vivo using the burn wound healing model on wistar albino rats. [ABSTRACT FROM AUTHOR]