# Fungi-Templated Silver Nanoparticle Composite: Synthesis, Characterization, and Its Applications
## 3 Results and Discussion  
### Morphological Characterization  
Biogenic AgNPs were prepared economically using a plant extract rich in secondary metabolites that facilitates the stable synthesis. A colloidal suspension of AgNPs was used to synthesize FH-AgNPs. The hybrid stable structure of FH-AgNPs was produced due to the accumulation of NPs on the surface of fungal hyphae. The thicknesses of these microstructure depend on the incubation period, wherein the NPs assemble as multilayers on the biomass. Studies emphasize that heavy metals such as silver can interfere with fungal growth and metabolism, and hence spores were germinated to adequate biomass in nutritional media devoid of AgNPs. The harvested biomass was suspended in AgNPs that serve as a framework for the self-assembling of NPs to form stable heterogeneous microtubules. Fungal cells, especially the chitin and chitosan, are associated with amino groups that encourage effective assembling of AgNPs on hyphae due to the electrostatic attraction between the fungal cell wall and negatively charged AgNPs. Furthermore, fungi secrete adhesive proteins and project glycoproteins on the surface of the cell wall that can also improve the self-assembling of nanoparticles [22; 23].  
In order to investigate the functional properties of the synthesized composite, the morphology and the associated parameters must be studied thoroughly. The morphology of the synthesized FH-AgNPs was determined using SEM and EDAX analysis with elemental mapping. The SEM images suggest that the fungal mycelium is retained after bio-templating and the EDS analysis indicates the presence of Ag in the microstructures. It was found that during bio-templating, the fungal hyphae collapse to form a sheet-like structure, and the SEM images (Figure 2a,b) were obtained by tearing off the upper layer which exposed the fungal hyphae. When the fungus is subjected to environmental stress, it tends to produce numerous secondary metabolites such as hydrophobic proteins, glycopteins, and lipids that are hydrophobic in nature. The hydrophobic interactions between the nanoparticles and the metabolites produced by the fugal hyphae result in binding of the nanoparticles. The EDS analysis shows that the atomic weight percentage of Ag is 83.31%, suggesting a uniform distribution of AgNPs over the fungal hyphae (Figure 2c). Upon analysis of the results obtained from SEM and EDS, it can be clearly seen that the mycelium remains intact after integrating AgNPs onto it, thereby forming tubular structures which can be utilized for various applications. The fungal mycelium acts as a solid support for the AgNPs, wherein it efficiently adheres to the mycelium via various non-covalent interactions.  
Figure 3 depicts the XRD patterns of AgNPs and FH-AgNPs. The diffraction patterns obtained for FH-AgNPs are quite like the diffraction patterns procured for AgNPs. For FH-AgNPs, the characteristic diffraction peaks (111, 200, 320, and 311) for Ag appear at 38.04\({}^{\circ}\), 44.21\({}^{\circ}\), 64.4\({}^{\circ}\), and 77.3\({}^{\circ}\), respectively [24]. The comparative XRD analysis of AgNPs and FH-AgNPs confirms the formation of the silver nanoparticle fungi composite, wherein the AgNPs are efficiently doped on the filamentous fungi. The adopted methodology for the generation of the FH-AgNP composite proves to be an efficient macroscale assembly of nanoparticles, wherein the unique properties of individual nanoparticles are translated into macroscopic materials.  
Figure 2: SEM image of FH-AgNP composite: (a) 1 \(\upmu\)m magnification; (b) 10 \(\upmu\)m magnification. (c) Elemental analysis of FH-AgNP composite.