ORIGINAL ARTICLE Biosynthesis of silver nanoparticles from Aloe vera leaf extract and antifungal activity against Rhizopus sp. and Aspergillus sp. Shreya Medda • Amita Hajra • Uttiya Dey • Paulomi Bose • Naba Kumar Mondal Received: 4 November 2014 / Accepted: 28 November 2014 / Published online: 11 December 2014 Ó The Author(s) 2014. This article is published with open access at Springerlink.com Abstract Silver nanoparticles are receiving increasing attention in the field of agriculture. This study aims at evaluating the antifungal properties of green synthesised silver nanoparticles (AgNPs) from Aloe vera leaf extract against two pathogenic fungus Rhizopus sp. and Aspergil- lus sp. Results revealed that synthesised nanoparticles showed strong absorption maximum at 400 nm corre- sponding to the surface plasmon resonance. The prepared nanoparticles were characterized by SEM, FT-IR and UV– Vis spectroscopy. From the scanning photograph it is clear that particles are heterogeneous in shape such as rectan- gular, triangular and spherical with uniform distribution. FT-IR study showed sharp absorption peaks at 1,631 and 3,433 cm -1 for amide and alcoholic hydroxide groups, respectively. On the other hand, synthesised silver nano- particles showed highest antifungal activity against Aspergillus sp. than Rhizopus sp. by application of 100 lL of 1 M silver nanoparticles with maximum inhibition of the growth of fungal hyphae. However, microscopic observa- tion revealed that synthesised nanoparticles caused detri- mental effects on conidial germination along with other deformations such as structure of cell membrane and inhibited normal budding process of both the tested spe- cies. Therefore, it has been concluded that Aloe vera leaf extract origin silver nanoparticles have tremendous poten- tiality towards controlling pathogenic fungus. However, further research is needed to check the efficacy of size- dependent AgNPs on different species of fungus. Keywords AgNPs Á Green synthesis Á Aloe vera leaf Á Antifungal effect Á Rhizopus sp. and Aspergillus sp. Introduction The term nanoparticle is used to describe a particle with size in the range of 1–100 nm (Yehia and Al-Sheikh 2014). They tend to react differently than larger particles of the same composition because of their large surface area, thus allowing them to be used in novel applications (Abou et al. 2010). Moreover, they serve as the funda- mental building block of nanotechnology (Vahabi et al. 2011). Nowadays there is a wide application of nano- particles in diverse fields including catalysis, energy, chemistry and medicine (Yehia and Al-Sheikh 2014). Nanotechnology approaches to control disease in human and plants have recently been increasing greatly and the unique physicochemical properties of nano-sized metal particles make them successful in biology and medicine (Jo et al. 2012). The current understanding of potential risks associated with the release of these materials in the environment for human and animal health is still insuf- ficient (Wang et al. 2012). However, very recently Verano-Braga et al. (2014) reported that the toxicity of AgNPs depends upon both dosage and particle size. Metal nanoparticles show large surface to volume ratio and exhibit antimicrobial properties due to their ability to interact with cellular membranes through disruption of cell wall structure (Ahmad et al. 2013; Trop et al. 2006). Especially silver has long been known for its strong toxicity against a wide range of micro organisms including bacteria and fungi (Narayanan and Park 2014). There are numerous methods for synthesis of silver nanoparticles, but, mostly used chemical methods, S. Medda Á A. Hajra Á U. Dey Á P. Bose Á N. K. Mondal (&) Environmental Chemistry Laboratory, Department of Environmental Science, The University of Burdwan, Burdwan 713104, India e-mail: nkmenvbu@gmail.com 123 Appl Nanosci (2015) 5:875–880 DOI 10.1007/s13204-014-0387-1