Selenium nanoparticles (SeNPs) are gaining importance in the field of medicines due to their high surface area and unique properties than their other forms of selenium. In this study, biogenic selenium nanoparticles (B-SeNPs) were synthesized using cyanobacteria and their bioactivities (antioxidant, antimicrobial, anticancer and biocompatibility) were determined for comparison with commercially available chemically synthesized selenium nanoparticles (C-SeNPs). Color change of reaction mixture from sky blue to orange-red indicated the synthesis of biogenic SeNPs (B-SeNPs). UV–Vis spectra of the reaction mixture exhibited peak at 266 nm. During optimization, 30 °C of temperature, 24 h of time and 1:2 concentration ratio of sodium selenite and cell extract represented the best condition for SeNPs synthesis. Various functional groups and biochemical compounds present in the aqueous extract of Anabaena variabilis NCCU-441, which may have possibly influenced the reduction process of SeNPs were identified by FT-IR spectrum and GC–MS. The synthesized cyanobacterial SeNPs were orange red in color, spherical in shape, 10.8 nm in size and amorphous in nature. The B-SeNPs showed better anti-oxidant (DPPH, FRAP, SOR and ABTS assays), anti-microbial (antibacterial and antifungal) and anti-cancer activitities along with its biocompatibility in comparison to C-SeNPs suggesting higher probability of their biomedical application.
The emergence and spread of SARS-CoV-2 have threatened the world’s public health security. The COVID-19 pandemic has affected many countries and significantly smashed the global economy, and also affected the health of the environment. This has upraised many apprehensions about its high transmission rate. Even though the most important routes of its transmission include direct contact and respiratory droplets, the infection through non-direct contacts also plays an important role. The increasing demand for intensive healthcare, escalating death toll and disruption in supply chains and trade have directed to mass implementation of testing, quarantine, and lockdown to restrain virus transmission. The lockdown has been a boon and a bane as well when it comes to the health of the environment. It had improved the air and water quality since the industrial activities were banned and therefore there was no addition of pollutants in the environment, but the usage of plastic-based personal protective equipment (PPE) and other medical waste has simultaneously resulted in huge plastic pollution that is choking seas and marine lives. The precautionary measures given by the United Nations Environment Programme in its COVID response factsheets suggest ways to reduce medical waste and to prevent the spread of the present pandemic. The recent green innovations and environmental stringency programs have resulted in reducing the threats to the environment that would eventually help in inhibiting the spread of such pandemics. In addition, proper measures should be adopted to safeguard the complete health of humans and the environment to execute safety and sustainable development that will help in achieving a stable biome.
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