Biofilm is the self-synthesized, mucus-like extracellular polymeric matrix that acts as a key virulence factor in various pathogenic microorganisms, thereby posing a serious threat to human health. It has been estimated that around 80% of hospital-acquired infections are associated with biofilms which are found to be present on both biotic and abiotic surfaces. Antibiotics, the current mainstream treatment strategy for biofilms are often found to be futile in the eradication of these complex structures, and to date, there is no effective therapeutic strategy established against biofilm infections. In this regard, nanotechnology can provide a potential platform for the alleviation of this problem owing to its unique size-dependent properties. Accordingly, various novel strategies are being developed for the synthesis of different types of nanoparticles. Bio-nanotechnology is a division of nanotechnology which is gaining significant attention due to its ability to synthesize nanoparticles of various compositions and sizes using biotic sources. It utilizes the rich biodiversity of various biological components which are biocompatible for the synthesis of nanoparticles. Additionally, the biogenic nanoparticles are eco-friendly, cost-effective, and relatively less toxic when compared to chemically or physically synthesized alternatives. Biogenic synthesis of nanoparticles is a bottom-top methodology in which the nanoparticles are formed due to the presence of biological components (plant extract and microbial enzymes) which act as stabilizing and reducing agents. These biosynthesized nanoparticles exhibit anti-biofilm activity via various mechanisms such as ROS production, inhibiting quorum sensing, inhibiting EPS production, etc. This review will provide an insight into the application of various biogenic sources for nanoparticle synthesis. Furthermore, we have highlighted the potential of phytosynthesized nanoparticles as a promising antibiofilm agent as well as elucidated their antibacterial and antibiofilm mechanism.

The emergence of highly virulent CoVs (SARS-CoV-2), the etiologic agent of novel ongoing “COVID-19” pandemics has been marked as an alarming case of pneumonia posing a large global healthcare crisis of unprecedented magnitude. Currently, the COVID-19 outbreak has fueled an international demand in the biomedical field for the mitigation of the fast-spreading illness, all through the urgent deployment of safe, effective, and rational therapeutic strategies along with epidemiological control. Confronted with such contagious respiratory distress, the global population has taken significant steps towards a more robust strategy of containment and quarantine to halt the total number of positive cases but such a strategy can only delay the spread. A substantial number of potential vaccine candidates are undergoing multiple clinical trials to combat COVID-19 disease, includes live-attenuated, inactivated, viral-vectored based, sub-unit vaccines, DNA, mRNA, peptide, adjuvant, plant, and nanoparticle-based vaccines. However, there are no licensed anti-COVID-19 drugs/therapies or vaccines that have proven to work as more effective therapeutic candidates in open-label clinical trial studies. To counteract the infection (SARS-CoV-2), many people are under prolonged treatment of many chemical drugs that inhibit the PLpro activity (Ribavirin), viral proteases (Lopinavir/Ritonavir), RdRp activity (Favipiravir, Remdesivir), viral membrane fusion (Umifenovir, Chloroquine phosphate (CQ), Hydroxychloroquine phosphate (HCQ), IL-6 overexpression (Tocilizumab, Siltuximab, Sarilumab). Mesenchymal Stem Cell therapy and Convalescent Plasma Therapy have emerged as a promising therapeutic strategy against SARS-CoV-2 virion. On the other hand, repurposing previously designed antiviral agents with tolerable safety profile and efficacy could be the only promising approach and fast response to the novel virion. In addition, research institutions and corporations have commenced the redesign of the available therapeutic strategy to manage the global crisis. Herein, we present succinct information on selected anti-COVID-19 therapeutic medications repurposed to combat SARS-CoV-2 infection. Finally, this review will provide exhaustive detail on recent prophylactic strategies and ongoing clinical trials to curb this deadly pandemic, outlining the major therapeutic areas for researchers to step in.

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Comparative role of mechanisms such as proppant crushing, embedment, diagenesis and fines migration is not well understood regarding hydraulic fracture conductivity. In this study, we have measured the long term permeability changed in the proppant pack under downhole conditions of temperature, confining pressure, pore pressure and fluid salinity. Major part of this study investigates proppant diagenesis and its role in hydraulic fracture conductivity reduction. Diagenesis is defined as any change in the proppant/shale material after proppant placement. Proppant indentation on the shale surface was also studied along with changes in chemical composition of the exit brine. Diverse types of secondary growths were observed both on the proppant as well as the shale surface. Most of the secondary growth using the quartz proppant and low flow rate was observed near the shale edges where the brine velocity was low. Ceramic proppant showed the most secondary growth, while resin coated proppant showed no growth. The pH of the exit fluid of several tests show dependence on carbonate content of shale. Significant permeability change that was observed with high flow rate tests was not observed at low flow rates. For quartz proppant, considerable amount of proppant breakage and indentation was observed. Fines generation causing permeability reduction was observed in tests conducted with quartz and ceramic proppants but not resin coated proppants. Indentation depth showed dependence on proppant type and distribution. Introduction Hydraulic fracturing is conducted to create a pathway for the hydrocarbons to flow into the wellbore from the reservoir. Fracturing fluid under very high pressure is pumped along with proppants during this procedure. While the high hydraulic pressure helps in fracture initiation and propagation, the proppant helps in keeping the fracture open after pressure removal for easy flow of hydrocarbons. Economic production from shales is attributed mainly to hydraulic fracturing. Shales exhibit very low permeability, usually in the range of 10-1000 nanodarcies. At such low permeability, the use of multistage hydraulic fracturing is inevitable. Proppants are pumped during the hydraulic fracturing process. Their interaction with the shale matrix and the surrounding liquid is important to understand because this governs the long term permeability of the fracture. This paper discusses the results of long term studies conducted at simulated reservoir conditions to study the proppant behavior and associated fracture permeability.

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