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SARS-CoV-2 (COVID-19) spreads and develops quickly worldwide as a new global crisis which has left deep socio-economic damage and massive human mortality. This virus accounts for the ongoing outbreak and forces an urgent need to improve antiviral therapeutics and targeted diagnosing tools. Researchers have been working to find a new drug to combat the virus since the outbreak started in late 2019, but there are currently no successful drugs to control the SARS-CoV-2, which makes the situation riskier. Very recently, new variant of SARS-CoV-2 is identified in many countries which make the situation very critical. No successful treatment has yet been shown although enormous international commitment to combat this pandemic and the start of different clinical trials. Nanomedicine has outstanding potential to solve several specific health issues, like viruses, which are regarded a significant medical issue. In this review, we presented an up-to-date drug design strategy against SARS-CoV-2, including the development of novel drugs and repurposed product potentials were useful, and successful drugs discovery is a constant requirement. The use of nanomaterials in treatment against SARS-CoV-2 and their use as carriers for the transport of the most frequently used antiviral therapeutics are discussed systematically here. We also addressed the possibilities of practical applications of nanoparticles to give the status of COVID-19 antiviral systems.

Hydrogen (H2) is one of the most promising renewable energy sources, anaerobic bacterial H2 fermentation is considered as one of the most environmentally sustainable alternatives to meet the potential fossil fuel demand. Bio-H2 is the cleanest and most effective source of energy provided by the dark fermentation utilizing organic substrates and different wastewaters. In this study, the bio-H2 production was achieved by using the bacteria Acinetobacter junii-AH4. Further, optimization was carried out at different pH (5.0–8.0) in the presence of wastewaters as substrates (Rice mill wastewater (RMWW), Food wastewater (FWW) and Sugar wastewater (SWW). In this way, the optimized experiments excelled with the maximum cumulative H2 production of 566.44 ± 3.5 mL/L (100% FWW at pH 7.5) in the presence of Acinetobacter junii-AH4. To achieve this, a bioreactor (3 L) was employed for the effective production of H2 and Acinetobacter junii-AH4 has shown the highest cumulative H2 of 613.2 ± 3.0 mL/L, HPR of 8.5 ± 0.4 mL/L/h, HY of 1.8 ± 0.09 mol H2/mol glucose. Altogether, the present study showed a COD removal efficiency of 79.9 ± 3.5% by utilizing 100% food wastewater at pH 7.5. The modeled data established a batch fermentation system for sustainable H2 production. This study has aided to achieve an ecofriendly approach using specific wastewaters for the production of bio-H2.

The development of effective and reliable drugs in the fight against malaria and cancer represents a crucial challenge in modern parasitology. The present investigation focuses on a simple and novel strategy for the biological synthesis of silver nanoparticles (Ag NPs) using β-caryophyllene isolated from the leaf extract of Murraya koenigii, as reducing and stabilizing agent. UV–visible spectroscopy of the Ag NPs in aqueous suspension revealed strong surface plasmon resonance at 420 nm. Fourier transform infrared spectrum showed the various characteristic peaks of reducing functional groups. X-ray diffraction indicated 2 theta values confirming the Bragg’s refraction index of Ag NPs. Scanning electron microscopy showed the nanoparticle spherical shapes while transmission electron microscopy showed nanoparticle sizes ranging from 5 to 100 nm, with an average size of 29.42 nm. Ag NPs exhibited promising activity on chloroquine-sensitive Plasmodium falciparum (3D7) (IC50: 2.34 ± 0.07 µg/ml), as well as significant cytotoxic activity on lung cancer cells (IC50: 9.39 ± 0.08 µg/ml). Overall, β-caryophyllene synthesized Ag NPs could be further considered as a promising source for the development of cost effective and safer alternative drugs to treat malaria and cancer.

The bio-reduction of chloroauric acid (HAuCl4) into well dispersed gold nanoparticles (GNPs) was achieved using the Albizia amara Roxb. plant extract. The formation of GNPs was confirmed by a change of color from yellowish green to purple with a characteristic peak at 543 nm. Further, the characterization of the synthesized GNPs showed their crystalline nature, functional groups, size and dispersed shapes, purity and Bragg’s reflections of face centered cubic structure. The zeta potential analysis revealed that A. amara GNPs did not aggregate and were quite stable which is in agreement with the constancy found during the dynamic light scattering measurements. During the DPPH assay, the GNPs and leaf aqueous extract showed the scavenging activity of 74 and 65 %, respectively and their in vitro IC50 inhibitory values (µg ml−1) were; 47.77 (HeLa) and 72.28 (Vero). The Gram positive, Staphylococcus aureus (MTCC 96) was found to be more sensitive to GNPs (16 mm) than the leaf aqueous extract (12 mm). In view of the recorded free radical, cytotoxic and antibacterial effects, the GNPs of A. amara could be a potential source for further research towards therapeutic development.

The Lantana camara Linn root extract derived gold nanoparticles (Au NPs) were characterized by Ultraviolet-Visible spectroscopy, X-ray diffraction, fourier transform-infrared, high resolution transmission electron microscopy, selected area electron diffraction pattern and energy dispersive X-ray analyses. In DPPH assay, the inhibitory concentration (IC50) of Au NPs and gallic acid was 24.17 and 5.39 μg/ml, whereas, for cytotoxicity assay, the IC50 of Au NPs was 17.72 and 32.98 μg/ml on MBA-MB-231 and Vero cells, respectively. Thus, the Au NPs possess significant in vitro antioxidant and cytotoxic properties which could be considered as potential alternate for the development of anticancer drug in future.