Contrasting effects of phytoplankton aging on microplastic antibiotic adsorption depending on species tolerance, and biofouling level.

Recent studies have reported conflicting results on the effects of biofouling on the adsorption behavior of microplastics (MPs). However, the underlying mechanisms driving the adsorption of MPs undergoing biofouling in aquatic environments remain unclear. This study examined the interactions between polyamide (PA), polyvinyl chloride (PVC) and polyethylene (PE) with two phytoplankton, namely cyanobacteria Microcystis aeruginosa and microalgae Chlorella vulgaris. Results indicated that MP effects on phytoplankton were dose- and crystalline-type dependent, with M. aeruginosa being more sensitive to MP exposure than C. vulgaris in the inhibitory order PA > PE > PVC. Analysis of antibiotic adsorption of the MPs showed significant contributions from CH/π interactions on PE and PVC and hydrogen bonding on PA, which decreased with phytoplankton biofouling and aging. Meanwhile, higher levels of extracellular polymeric substances on microalgae-aged MPs compared to cyanobacteria-aged MPs were conducive to adsorption of antibiotics, mainly through hydrophobic interactions. Overall, promotional and anti-promotional adsorption of antibiotics on MPs was induced by biofouling and aging of microalgae and cyanobacteria, respectively. This study provides deep insights into the specific mechanisms by which biofouling affects MP adsorption in aquatic environments, thus advancing our understanding of this critical environmental issue.

Therapeutic drugs for SARS-CoV-2 treatment: Current state and perspective.

The disease caused by viral pneumonia called severe acute respiratory syndrome coronavirus type-2 (SARS-CoV-2) declared by the World Health Organization is a global pandemic that the world has witnessed since the last Ebola epidemic, SARS and MERS viruses. Many chemical compounds with antiviral activity are currently undergoing clinical investigation in order to find treatments for SARS-CoV-2 infected patients. On-going drug-drug interaction examinations on new, existing, and repurposed antiviral drugs are yet to provide adequate safety, toxicological, and effective monitoring protocols. This review presents an overview of direct and indirect antiviral drugs, antibiotics, and immune-stimulants used in the management of SARS-CoV-2. It also seeks to outline the recent development of drugs with anti-coronavirus effects; their mono and combination therapy in managing the disease vis-à-vis their biological sources and chemistry. Co-administration of these drugs and their interactions were discussed to provide significant insight into how adequate monitoring of patients towards effective health management could be achieved.