Ultrasound accelerated the green and mild preparation of bioactive, coated, and biosynthesized silver nanoparticles by different leaf extracts

Biological methods have been recently found to be eco-friendly and cost-effective alternatives for synthesizing silver nanoparticles (AgNPs). This study highlights a green process wherein AgNPs were synthesized and coated by seven leaf extracts consisting of Piper betle L., Piper sarmentosum Roxb, Averrhoa carambola L., Syzygium aqueum (Burn.f.) Alstion, Syzygium nervosum A. Cunn. ex DC, Psidium guajava L., Couroupita surinamensis Mart. Ex Berg under the acceleration of ultrasound. The optimized synthesized and coated silver nanoparticles were characterized by UV–visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry, and field emission scanning electron microscopy. AgNPs were obtained with spherical and anisotropic shapes of different sizes. Furthermore, the antibacterial and antifungal activities of the synthesized and coated AgNPs illustrated that they can cause efficiently against gram-positive and -negative bacteria, fairly against mold. Generally, the biosynthesized and coated AgNPs possess various nanoparticle shapes, sizes, and even bioactive properties substantially depending on the kind of extracts.