Biogenic synthesis of nanoparticles (NPs) is emerging as a feasible, economical, sustainable, biocompatible, and alternative approach to utilize biomolecules derived from the organisms. The use of microbes or their metabolites for biogenic NPs synthesis also imparts the biological active antimicrobial potential of the organism which has widened the application of NPs in an effective and economically friendly way. The biological reduction of metals provides NPs of desirable size and morphology with higher physiochemical characteristics, lower toxicity, and high stability. Fungi are the most preferred for the biogenic synthesis of NPs due to high biomass production, secretion of a high quantity of extracellular nano-particles stabilizing proteins, ease in handling, and high metal tolerance. The present review provides an overview of the biogenic synthesis of metal NPs using micro and macrofungi, mechanism, their optimization process and their applications in the field of agriculture.

Green tea (GT) is derived from the leaves of Camellia sinensis implicated in a wide range of health attributes. In the present comprehensive study, methanolic, acetone and aqueous extract of leaves of C. sinensis var. sinensis [Kashmir (KW), Uttarakhand (IP & PN)] and C. sinensis var. assamica (Assam, AT) were explored for their phytoconstituents. Solvent extracts of GT cultivars showed rich presence of phytoconstituents in comparison with aqueous extracts. The methanolic extract of AT and acetone extract of KW showed highest total phenol content (18.32 ± 0.357 mg of GAE equivalent/g of sample) and total flavonoid content (29.25 ± 0.015 mg of catechin equivalent/g of sample), respectively. All the cultivars revealed higher free radical scavenging activity in the range of 73.80 ± 0.152 to 82.40 ± 0.004 % confirming antioxidant potentials. The HPLC analysis of purified residue procured from solvent partitioning depicted AT with highest concentration of epigallocatechin gallate (EGCg) i.e., 154.7 ± 4.949 mg/g followed by Kashmir and Uttarakhand GT cultivars. The present study revealed that Assam GT could be a potent herbal candidate with multiple nutraceutical applications. However, significant investigation of the cultivars is to be done to further explore the EGCg-dependent activity of GT for herbal drug development.

Since the COVID‐19 outbreak, the severe acute respiratory syndrome coronavirus 2 (SARS‐COV‐2) virus has evolved into variants with varied infectivity. Vaccines developed against COVID‐19 infection have boosted immunity, but there is still uncertainty on how long the immunity from natural infection or vaccination will last. The present study attempts to outline the present level of information about the contagiousness and spread of SARS‐CoV‐2 variants of interest and variants of concern (VOCs). The keywords like COVID‐19 vaccine types, VOCs, universal vaccines, bivalent, and other relevant terms were searched in NCBI, Science Direct, and WHO databases to review the published literature. The review provides an integrative discussion on the current state of knowledge on the type of vaccines developed against SARS‐CoV‐2, the safety and efficacy of COVID‐19 vaccines concerning the VOCs, and prospects of novel universal, chimeric, and bivalent mRNA vaccines efficacy to fend off existing variants and other emerging coronaviruses. Genomic variation can be quite significant, as seen by the notable differences in impact, transmission rate, morbidity, and death during several human coronavirus outbreaks. Therefore, understanding the amount and characteristics of coronavirus genetic diversity in historical and contemporary strains can help researchers get an edge over upcoming variants.

In this study, multifunctional lithium-doped bismuth ferrite [BiFe_1−xLi_xO₃]-graphene nanocomposites (x = 0.00, 0.02, 0.04, 0.06) were synthesized by a sol-gel and ultrasonication assisted chemical reduction method. X-ray diffraction and FESEM electron microscopy techniques disclosed the nanocomposite phase and nanocrystalline nature of [BiFe_1−xLi_xO₃]-graphene nanocomposites. The FESEM images and the EDX elemental mapping revealed the characteristic integration of BiFe_1−xLi_xO₃ nanoparticles (with an average size of 95 nm) onto the 2D graphene layers. The Raman spectra of the [BiFe_1−xLi_xO₃]-graphene nanocomposites evidenced the BiFe_1−xLi_xO₃ and graphene nanostructures in the synthesized nanocomposites. The photocatalytic performances of the synthesized nanocomposites were assessed for ciprofloxacin (CIP) photooxidation under UV-visible light illumination. The photocatalytic efficiencies of [BiFe_1−xLi_xO₃]-graphene nanocomposites were measured to be 42%, 47%, 43%, and 10%, for x = 0.00, 0.02, 0.04, 0.06, respectively, within 120 min illumination, whereas the pure BiFeO₃ nanoparticles were 21.0%. BiFe_1−xLi_xO₃ nanoparticles blended with graphene were explored as cathode material and tested in a microbial fuel cell (MFC). The linear sweep voltammetry (LSV) analysis showed that the high surface area of BiFeO₃ was attributed to efficient oxygen reduction reaction (ORR) activity. The increasing loading rates of (0.5–2.5 mg/cm²) [BiFe_1−xLi_xO₃]-graphene composite on the cathode surface showed increasing power output, with 2.5 and 2 mg/cm² achieving the maximum volumetric power density of 8.2 W/m³ and 8.1 W/m³, respectively. The electrochemical impedance spectroscopy (EIS) analysis showed that among the different loading rates used in this study, BiFeO₃, with a loading rate of 2.5 mg/cm², showed the lowest charge transfer resistance (R_ct). The study results showed the potential of [BiFe_1−xLi_xO₃]-graphene composite as a cost-effective alternative for field-scale MFC applications.