Exploring possible strategies for treating SARS-CoV-2 in sewage wastewater: A review of current research and future directions.

The advent of acute respiratory coronavirus disease (COVID-19) is convoyed by the shedding of the virus in stool. Although inhalation from person-to-person and aerosol/droplet transmission are the main modes of SARS-Coronavirus-2 (SARS-CoV-2) transmission, currently available evidence indicates the presence of viral RNA in the sewerage wastewater, which highlights the need for more effective corona virus treatment options. In the existing COVID-19 pandemic, a substantial percentage of cases shed SARS-CoV-2 viral RNA in their faeces. Hence the treating this sewerage wastewater with proper surveillance is essential to contain this deadly pathogen from further transmission. Since, the viral disinfectants will not be very effective on sewerage waste as organic matter, and suspended solids in water can protect viruses that adsorb to these particles. More effective methods and measures are needed to prevent this virus from spreading. This review will explore some potential methods to treat the SARS-CoV-2 infected sewerage wastewater, current research and future directions.

Fabrication of asymmetric nanostarch reinforced Chitosan/PVP membrane and its evaluation as an antibacterial patch for in vivo wound healing application.

Starch is an abundant, relatively inexpensive and ecofriendly materials which can be easily convert into nanoparticle and also as filler for the preparation of bionanocomposite for wound dressing application. Symmetric and asymmetric Chitosan(C)/PVP(P) films containing porous structure supported with nanostarch (NS) were prepared by salt leaching method for wound dressing application. Symmetric Chitosan/PVP/Nanostarch (CPNS) film with 1% and 3% wt nanostarch was prepared without coating of stearic acid whereas asymmetric Chitosan/PVP/Nanostarch-Stearic acid (CPNS-S) film was prepared by coating of stearic acid. The stearic acid coated surface possesses hydrophobic water repellent, microporous, bacterial anti adhesion property and the stearic acid uncoated hydrophilic surface shows superior antibacterial and noncytotoxicity property with highly porous character. All the symmetric and asymmetric films exhibit almost same mechanical, barrier, swelling and hemolytic property reveals that the stearic acid does not affect the physical and hemolytic property whereas the concentration of nanostarch greatly influence the above property. The reinforcement of nanostarch with chitosan and PVP was proved by TEM and SEM analysis. The CPNS1%-S film shows excellent S. aureus anti adhesion property. Furthermore, the in vivo excision-type wound healing proved that the CPNS1%-S film enhanced the healing effect and increased re-epithelialization and collagen formation.

Novel asymmetric chitosan/PVP/nanocellulose wound dressing: In vitro and in vivo evaluation.

The present study was to develop a novel chitosan based symmetric and asymmetric bionanocomposite for potential wound dressing application. Chitosan (C)/Poly (vinyl pyrrolidone) (P)/nanocellulose (NC) membrane were fabricated by salt leaching method with the addition of 3% and 5% wt of nanocellulose. To obtain asymmetric material one side of the membrane was coated by stearic acid (S) which could form hydrophobic surface and another side acts as a hydrophilic surface. Nanocellulose of size 2-10nm was synthesized and characterized by TEM analysis. SEM showed the hydrophilic surface of asymmetric bionanocomposite consists of porous structure and hydrophobic surface is smooth and homogeneous. The results revealed that the Chitosan/PVP/Nanocellulose 3%-Stearic acid (CPNC3%-S) had a moderate swelling ratio, porosity, barrier and mechanical properties. Incorporation of nanocellulose into chitosan/PVP matrix could enhance the antibacterial activity. The hydrophobic surface of the CPNC3%-S bionanocomposite shows water repellent and antiadhesion properties towards E. coli bacteria and also the hydrophilic surface exhibit excellent antibacterial property and cytotoxicity towards bacterial pathogens. In vivo wound healing test shows better re-epithelialization and wound contraction compared with control and Chitosan/PVP-stearic acid (CP-S) bionanocomposite. Asymmetric bionanocomposite Chitosan/PVP/Nanocellulose coated with 3%-Stearic acid (CPNC3%-S) exhibited very good invitro cytocompatibility and enabled a faster wound healing than symmetric dressing, hence showing great potential to be applied as wound dressings.

Processing and characterization of chitosan/PVA and methylcellulose porous scaffolds for tissue engineering.

Biomimetic porous scaffold chitosan/poly(vinyl alcohol) CS/PVA containing various amounts of methylcellulose (MC) (25%, 50% and 75%) incorporated in CS/PVA blend was successfully produced by a freeze drying method in the present study. The composite porous scaffold membranes were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), swelling degree, porosity, degradation of films in Hank's solution and the mechanical properties. Besides these characterizations, the antibacterial activity of the prepared scaffolds was tested, toward the bacterial species Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli). FTIR, XRD and DSC demonstrated that there was strong intermolecular hydrogen bonding between the molecules of CS/PVA and MC. The crystalline microstructure of the scaffold membranes was not well developed. SEM images showed that the morphology and diameter of the scaffolds were mainly affected by the weight ratio of MC. By increasing the MC content in the hybrid scaffolds, their swelling capacity and porosity increased. The mechanical properties of these scaffolds in dry and swollen state were greatly improved with high swelling ratio. The elasticity of films was also significantly improved by the incorporation of MC, and the scaffolds could also bear a relative high tensile strength. These findings suggested that the developed scaffold possess the prerequisites and can be used as a scaffold for tissue engineering.