Abstract
In this study, spider cobweb as a novel biomaterial was used for the green synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs were characterized using UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy. The efficacy of biosynthesized particles as antibacterial agents was evaluated using multi-drug resistant clinical bacterial isolates through sensitivity testing with AgNPs and combination of AgNPs with some selected antibiotics. In addition, the potential application of the particles as additives in paints was demonstrated using some bacterial and fungal isolates. The synthesized AgNPs which were dark brown in color displayed maximum absorbance at the wavelength of 436 nm. It was observed that the reaction mixture of 1:40 (extract:AgNO3 solution) at pH of 8.5 produced particles with maximum absorbance at 436 nm. The FTIR spectrum showed peaks at 3298, 2359, 2089, and 1635 cm−1, indicating that proteins were the capping and stabilization molecules in the synthesis of AgNPs. The particles were spherical in shape with size ranging about 3–50 nm. The energy-dispersive X-ray analysis showed the presence of silver as the most prominent metal, while the selected area electron diffraction pattern conformed to the face-centered cubic phase and crystalline nature of AgNPs. The AgNPs inhibited the growth of several bacterial isolates including S. aureus, E. coli, Klebsiella granulomatis and P. aeruginosa in the range of 10–17 mm at concentration of 100 µg/ml. It was also demonstrated that AgNPs potentiated the activities of augmentin, ofloxacin and cefixime in the AgNP–antibiotic synergy studies. Similarly, the inclusion of AgNPs as additive in white emulsion paint led to the total inhibition of growth of E. coli, P. aeruginosa, Aspergillus niger and A. fumigatus. To the best of our knowledge, this is the first report of the use of cobweb for the green synthesis of AgNPs. The immense antimicrobial activities of the particles can be explored in the creation of novel products, where it can be used as additive to protect materials against microbial attack.
Highlights
The green synthesis of nanoparticles has continued to receive unprecedented attention due to the simplicity of the process, less handling of chemicals and eco-friendliness (Salem et al 2014)
Spider cobwebs have been used for the monitoring of pollution in industrial and residential areas (Hose et al 2002; Ayedun et al 2013), while spiders have been used as bio-control agents in reducing populations of insect pests on farmlands (Maloney et al 2003)
This study has led to the green synthesis of AgNPs using the extract of spider cobweb under ambient condition
Summary
The green synthesis of nanoparticles has continued to receive unprecedented attention due to the simplicity of the process, less handling of chemicals and eco-friendliness (Salem et al 2014). Several authors have used bacteria, fungi, algae and plant extracts for the green synthesis of metal nanoparticles (Shivaji et al 2011; Salem et al 2014; Augustine et al 2014; Shanmugam et al 2014; Nazeruddin et al 2014; Rajeshkumar et al 2014; Raliya and Tarafdar 2014; Mishra et al 2014; Lateef et al 2015a, b; El-Batal et al 2015). There are approximately 40,000 species of spiders in the World (Insect Identification 2015) out of nearly 1.7 million described species of plants, animals, fungi, bacteria, and protists (DMNS 2015). Spiders are 8-legged creatures that have chitinous coverings and two body regions, the cephalothorax (head and thorax as one external unit) and the abdomen (Glime 2013). They have various hairs that penetrate their chitinous covering
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