Functional Attributes of Myco-Synthesized Silver Nanoparticles from Endophytic Fungi: A New Implication in Biomedical Applications

Abstract

To develop a benign nanomaterial from biogenic sources, we have attempted to formulate and fabricate silver nanoparticles synthesized from the culture filtrate of an endophytic fungus Penicillium oxalicum strain LA-1 (PoAgNPs). The synthesized PoAgNPs were exclusively characterized through UV-vis absorption spectroscopy, Fourier Transform Infra-Red spectroscopy (FT-IR), X-ray powder diffraction (XRD), and Transmission Electron Microscopy (TEM) with energy dispersive X-ray spectroscopy (EDX). The synthesized nanoparticles showed strong absorbance around 430 nm with surface plasmon resonance (SPR) and exhibited a face-centered cubic crystalline nature in XRD analysis. Proteins presented in the culture filtrate acted as reducing, capping, and stabilization agents to form PoAgNPs. TEM analysis revealed the generation of polydispersed spherical PoAgNPs with an average size of 52.26 nm. The PoAgNPs showed excellent antibacterial activity against bacterial pathogens. The PoAgNPs induced a dose-dependent cytotoxic activity against human adenocarcinoma breast cancer cell lines (MDA-MB-231), and apoptotic morphological changes were observed by dual staining. Additionally, PoAgNPs demonstrated better larvicidal activity against the larvae of Culex quinquefasciatus. Moreover, the hemolytic test indicated that the as-synthesized PoAgNPs are a safe and biocompatible nanomaterial with versatile bio-applications.

Keywords: antibacterial activity; endophytic fungi; silver nanoparticles.

Figure 1

Morphology of P. oxalicum LA-1.

Figure 2

GC-MS chromatogram for ethyl acetate extract of P. oxalicum LA-1.

Figure 3

Color change formation and optimization of PoAgNPs. (a) UV absorption spectrum of PoAgNPs (fungal extract vs. silver nitrate). (b) Effect of pH on the synthesis of PoAgNPs. (c) Effect of temperature on the synthesis of PoAgNPs. (d) UV–visible spectroscopy produced intense SPR spectra at 410 nm in optimized conditions.

Figure 4

(A) FT-IR analysis of PoAgNPs. (B) XRD of PoAgNPs.

Figure 5

(a–c) TEM analysis of PoAgNPs. (d) SAED pattern of PoAgNPs. (e) Particle size histogram of PoAgNPs. (f) EDAX analysis of PoAgNPs.

Figure 6

(A) Zeta potential of PoAgNPs. (B) Dynamic light scattering of PoAgNPs.

Figure 7

(A) Hemolytic activity of PoAgNPs. (B) Antibacterial activity of PoAgNPs (mean ± SE followed by different letters (a–e) within the same row were significantly different (Tukey’s test, p < 0.05)).

Figure 8

MIC values were confirmed by Resazurin dye assay.

Figure 9

Fluorescence images of bacterial pathogens treated with MIC values of PoAgNPs. White arrows indicate the damaged bacterial cells.

Figure 10

Cell proliferation analysis by MTT assay. Different concentrations of PoAgNPs (0 to 100 μg/mL) were used to treat MB-MDA-231 cancer cell lines. The proliferation rates were expressed as mean ± SD of the three experiments.

Figure 11

AO/EB dual staining apoptotic assay.

Figure 12

Larvicidal activity of PoAgNPs. Mean ± SE followed by different letters were significantly different (Tukey’s test, p < 0.05).

Figure 13

Light microscopic images of control- and PoAgNPs-treated mosquito larvae of C. quinquefasciatus with ×10 magnification.