Eco-Friendly Hierarchical Nanoporous Microfiber Respirator Filters Fabricated Using Rotary Jet Spinning Technology (RJS)

The current global health crisis caused by the SARS-CoV-2 virus (COVID-19) has increased the use of personal protective equipment, especially face masks, leading to the disposal of a large amount of plastic waste causing an environmental crisis due to the use of non-biodegradable and non-recyclable polymers, such as polypropylene and polyester. In this work, an eco-friendly biopolymer, polylactic acid (PLA), was used to manufacture hierarchical nanoporous microfiber biofilters via a single-step rotary jet spinning (RJS) technique. The process parameters that aid the formation of nanoporosity within the microfibers were discussed. The microstructure of the fibers was analyzed by scanning electron microscopy (SEM) and a noninvasive X-ray microtomography (XRM) technique was employed to study the three-dimensional (3D) morphology and the porous architecture. Particulate matter (PM) and aerosol filtration efficiency were tested by OSHA standards with a broad range (10-1000 nm) of aerosolized saline droplets. The viral penetration efficiency was tested using the phi X174 bacteriophage (similar to 25 nm) with an envelope, mimicking the spike protein structure of SARS-CoV-2. Although these fibers have a similar size used in N95 filters, the developed biofilters present superior filtration efficiency (similar to 99%) while retaining better breathability (<4% pressure drop) than N95 respirator filters.

Efficient, Breathable, and Compostable Multilayer Air Filter Material Prepared from Plant-Derived Biopolymers.

State-of-art face masks and respirators are fabricated as single-use devices using microfibrous polypropylene fabrics, which are challenging to be collected and recycled at a community scale. Compostable face masks and respirators can offer a viable alternative to reducing their environmental impact. In this work, we have developed a compostable air filter produced by electrospinning a plant-derived protein, zein, on a craft paper-based substrate. The electrospun material is tailored to be humidity tolerant and mechanically durable by crosslinking zein with citric acid. The electrospun material demonstrated a high particle filtration efficiency (PFE) of 91.15% and a high pressure drop (PD) of 191.2 Pa using an aerosol particle diameter of 75 ± 2 nm at a face velocity of 10 cm/s. We deployed a pleated structure to reduce the PD or improve the breathability of the electrospun material without compromising the PFE over short- and long-duration tests. Over a 1 h salt loading test, the PD of a single-layer pleated filter increased from 28.9 to 39.1 Pa, while that of the flat sample increased from 169.3 to 327 Pa. The stacking of pleated layers enhanced the PFE while retaining a low PD; a two-layer stack with a pleat width of 5 mm offers a PFE of 95.4 ± 0.34% and a low PD of 75.2 ± 6.1 Pa.

A mini review on the prospects of Fagara zanthoxyloides extract based composites: A remedy for COVID-19 and associated replica?

Studies are still being conducted to find a sustainable and long-lasting solution to the lethal consequences of the feared virus characterized as coronavirus disease (Covid-19) and its accompanying pathogenic replication, which pose a serious threat to human survival in the wake of its broad distribution. Since its emergence, researchers have investigated synthetic approaches in search of a dependable vaccine or treatment and curtail the spread of the virus and also enhance the health of a patient who has been affected. Unfortunately, the infection is yet to be entirely eradicated in many parts of the world. Despite the introduction of synthetic pharmaceuticals like remdesivir and derivatives of chloroquine, plant extracts may be an alternative reliable strategy that could successfully combat the operation of the virus. Herein, we investigated the prospects of fagara zanthoxyloides lam. (rutaceae) (syn. zanthoxylum zanthoxyloides), a well-known medicinal tree whose extracts have demonstrated success in treating many microbiological and viral-related infections. The distinctive plant extracts contain several bioactive phytochemicals with promising biological activity with minimal or no side effects and are being researched for a variety of applications, particularly in the pharmaceutical and medicinal industries. Consequently, in this review, we examined the crude extracts from the Fagara species and suggested that careful consideration should be given to its independent use or combination with other bioactive molecules, such as biopolymers and nano-metallic composites, to combat the terrifying Covid-19 virus and its associates. © 2023 Walter de Gruyter GmbH, Berlin/Boston 2023.

Kinetic Studies for the Release of Hydroxychloroquine Sulphate Drug (HCQ) In-vitro in Simulated Gastric and Intestinal Medium from Sodium Alginate and Lignosulphonic Acid Blends

Biodegradable polymeric blends are used to study the controlled release of Hydroxychloroquine sulphate (HCQ) as the model drug used extensively in COVID-19 treatments. HCQ drug is loaded in sodium alginate (NaAlg) and lignosulphonic acid (NaLS) blends as matrix are crosslinked using calcium chloride solution. Its release is evaluated in different pH mediums of simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The HCQ release data obtained during experimentation is used to study kinetics using different models to investigate polymeric relaxation's drug diffusion and mechanism in water-soluble HCQ drug. The drug release mechanism best fits the Higuchi model with Fickian diffusion as the primary polymeric relaxation mechanism. © 2023, Walailak University. All rights reserved.

Eco-Friendly Hierarchical Nanoporous Microfiber Respirator Filters Fabricated Using Rotary Jet Spinning Technology (RJS)

The current global health crisis caused by the SARS-CoV-2 virus (COVID-19) has increased the use of personal protective equipment, especially face masks, leading to the disposal of a large amount of plastic waste causing an environmental crisis due to the use of non-biodegradable and non-recyclable polymers, such as polypropylene and polyester. In this work, an eco-friendly biopolymer, polylactic acid (PLA), was used to manufacture hierarchical nanoporous microfiber biofilters via a single-step rotary jet spinning (RJS) technique. The process parameters that aid the formation of nanoporosity within the microfibers were discussed. The microstructure of the fibers was analyzed by scanning electron microscopy (SEM) and a noninvasive X-ray microtomography (XRM) technique was employed to study the three-dimensional (3D) morphology and the porous architecture. Particulate matter (PM) and aerosol filtration efficiency were tested by OSHA standards with a broad range (10-1000 nm) of aerosolized saline droplets. The viral penetration efficiency was tested using the ΦX174 bacteriophage (∼25 nm) with an envelope, mimicking the spike protein structure of SARS-CoV-2. Although these fibers have a similar size used in N95 filters, the developed biofilters present superior filtration efficiency (∼99%) while retaining better breathability (<4% pressure drop) than N95 respirator filters. © 2023 American Chemical Society

κ-Carrageenan/Sodium Alginate: A New Synthesis Route and Rapid Adsorbent for Hydroxychloroquine Drug

In recent years, the huge amounts of chemicals that are used as drugs and their derivatives have been exposed to the environment due to the COVID-19 pandemic. Some of these drugs (i.e. hydroxychloroquine (HCQ)) have a serious risk on aquatic media. In this study, carrageenan/sodium alginate (κC/Sa) was investigated as a biopolymer, environmentally friendly, and rapidly adsorbent to eliminate HCQ from its aqueous solution. The biopolymer (κC/Sa) was synthesized by free radical polymerization assisted by ultrasound in the presence of acrylic acid as cross-linkage and potassium persulfate as an initiator. The natural κC/Sa was characterized by FTIR, XRD, BET, BJH, and SEM techniques. The produced co-polymer had a mesoporous surface with high purity and significant thermal stability. The best parameters were determined to be 0.05 g biopolymer, 200 ppm initial HCQ concentration, salts, and pH = 7. The adsorption mechanism follows a pseudo second-order kinetic model, and the adsorption isotherm follows a Freundlich model, with qe reaching 89.8 mg/g at 500 ppm HCQ. Thermodynamic studies indicated that the adsorption of hydroxychloroquine drugs was an exothermic spontaneous process. © 2023, Gadjah Mada University. All rights reserved.

Antibacterial, Anti-Biofilm and Pro-Migratory Effects of Double Layered Hydrogels Packaged with Lactoferrin-DsiRNA-Silver Nanoparticles for Chronic Wound Therapy.

Antimicrobial resistance and biofilm formation in diabetic foot infections worsened during the COVID-19 pandemic, resulting in more severe infections and increased amputations. Therefore, this study aimed to develop a dressing that could effectively aid in the wound healing process and prevent bacterial infections by exerting both antibacterial and anti-biofilm effects. Silver nanoparticles (AgNPs) and lactoferrin (LTF) have been investigated as alternative antimicrobial and anti-biofilm agents, respectively, while dicer-substrate short interfering RNA (DsiRNA) has also been studied for its wound healing effect in diabetic wounds. In this study, AgNPs were complexed with LTF and DsiRNA via simple complexation before packaging in gelatin hydrogels. The formed hydrogels exhibited 1668% maximum swellability, with a 46.67 ± 10.33 µm average pore size. The hydrogels demonstrated positive antibacterial and anti-biofilm effects toward the selected Gram-positive and Gram-negative bacteria. The hydrogel containing AgLTF at 125 µg/mL was also non-cytotoxic on HaCaT cells for up to 72 h of incubation. The hydrogels containing DsiRNA and LTF demonstrated superior pro-migratory effects compared to the control group. In conclusion, the AgLTF-DsiRNA-loaded hydrogel possessed antibacterial, anti-biofilm, and pro-migratory activities. These findings provide a further understanding and knowledge on forming multipronged AgNPs consisting of DsiRNA and LTF for chronic wound therapy.

Characterization, optimization, and evaluation of preservative efficacy of carboxymethyl cellulose/hydromagnesite stromatolite bio-nanocomposite.

Currently, researchers are focusing on the development of nano-additive preservatives during the worldwide COVID-19 pandemic. This research aimed to constitute a small sized preservative nano-formulation which emerges from the biopolymer carboxymethyl cellulose (a green stabilizing agent) and hydromagnesite stromatolite (a fossilized natural additive). In this study, we investigated the optimization of the experimental design of carboxymethyl cellulose/hydromagnesite stromatolite (CMC/HS) bio-nanocomposites using a green and one-step sonochemical method at room temperature. In addition, we constructed a mathematical model which relates the intrinsic viscosity with all operating variables, and we carried out statistical error analysis to assess the validity of the proposed model. The characterization and chemical functional groups of CMC/HS bio-nanocomposites were determined by different advanced techniques such as SEM, HRTEM, DLS, FTIR, XRD, and BET. The challenge test was used to show the preservative efficacy of CMC/HS bio-nanocomposites against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Aspergillus brasiliensis. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltrazolium bromide (MTT) assay was performed on L929 cells to evaluate the in vitro cytotoxicity of CMC/HS bio-nanocomposites. According to the results, we showed that the synthesized CMC/HS bio-nanocomposites have no cytototoxic effects on L929 fibroblast cells and could be considered to be an alternative green nano-additive preservative against pathogenic microorganisms.

Polylactic acid/tapioca starch/banana peel-based material for colorimetric and electrochemical biosensing applications.

The rapidly growing electronic and plastic waste has become a global environmental concern. Developing advanced and environmentally safe agro-based materials is an emerging field with an enormous potential for applications in sensors and devices. Here, an agro-based material as membrane has been developed by incorporating tapioca starch and banana peel powder in polylactic acid, with uniform dispersibility and amorphous nature. The material was used for the development of electrochemical sensor for S-gene of SARS-CoV-2. Further, the membrane was used for the development of a non-invasive, colorimetric skin patch for the detection of glucose and a sensor for the assessment of fruit juice quality. Using OECD-recommended model systems, the developed membrane was found to be non-toxic towards aquatic and terrestrial non-target organisms. The developed conductive material opens new avenues in various electrochemical, analytical, and biological applications.

Chitosan-Based Formulations Intended as Protective Spray for Mask Surfaces in Prevention of Coronavirus Dissemination.

The extraordinary occurrence of COVID-19 by the fast expansion of viral infections has propelled particular interest in developing novel antiviral and virucidal agents to guarantee personal security. The main objective of this work is to propose novel formulations able to optimize the use of personal protection elements. In recent years, chitosan (CH) has attracted attention for being an interesting multifunctional, biodegradable, non-antigenic, non-toxic, and biocompatible natural polymer with antimicrobial properties. In this work, formulations based on a CH matrix containing silver, and Copper based nanoparticles have been developed. The novelty of this proposal is that almost liquid formulations have been reached, possessing verified properties to inhibit evolved virus such as herpes simplex type 1 (HSV-1) and bovine betacoronavirus (BCoV), the latter belonging to the same family of the well-known the well-known SARS-CoV-2. Besides antibacterial bioactivity; as well as the ability of these formulations to be easily sprayed on various surfaces, including conventional face masks, have been verified and discussed. The results presented in this contribution provide strong evidence on CH films as an ideal biosafe surface-protective for several daily used materials including the conventional face masks.

Fermentative bioconversion of food waste into biopolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) using Cupriavidus necator.

Dependency on plastic commodities has led to a recurrent increase in their global production every year. Conventionally, plastic products are derived from fossil fuels, leading to severe environmental concerns. The recent coronavirus disease 2019 pandemic has triggered an increase in medical waste. Conversely, it has disrupted the supply chain of personal protective equipment (PPE). Valorisation of food waste was performed to cultivate C. necator for fermentative production of biopolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The increase in biomass, PHBV yield and molar 3-hydroxy valerate (3HV) content was estimated after feeding volatile fatty acids. The fed-batch fermentation strategy reported in this study produced 15.65 ± 0.14 g/L of biomass with 5.32 g/L of PHBV with 50% molar 3HV content. This is a crucial finding, as molar concentration of 3HV can be modulated to suit the specification of biopolymer (film or fabric). The strategy applied in this study addresses the issue of global food waste burden and subsequently generates biopolymer PHBV, turning waste to wealth.

A New Antiviral Regimen Against SARS-CoV-2 Based on Nanoviricide’s Biopolymer (NV-CoV-2)

NV-CoV-2, a nanoviricide composed of covalently attached polyethylene glycol and alkyl pendants that are designed to bind free virion particles of multiple strains of coronaviruses in a broad-spectrum manner at multiple points. The binding interaction is like a nano-velcro-tape and may cause a lipid–lipid fusion between nanoviricide micelle and the lipid envelope of the virus. A nanoviricide can encapsulate the virus and dismantle it without any involvement of the host immune system, ultimately disabling the infectibility of the host cells. Thus, it may be expected to count a stronger and synergistic antiviral effect by combining NV-CoV-2 with other anti-coronavirus regimens like remdesivir. Furthermore, some ligands similar to the SARS-CoV S-protein are designed by molecular modeling and attached to the nanoviricide at the same site as where the cognate cellular receptor, ACE2, binds. As a result, a competitive binding inhibition may occur. A nanoviricide can encapsulate other antiviral compounds and protect them from serum-mediated degradation in vivo. This makes the antiviral compounds available for a longer period of time to interact with RNA polymerase and inhibit it. Altogether, a multipoint antiviral efficacy can be achieved with our nanoviricide, NV-CoV-2. Copyright © 2022 Chakraborty, Diwan, Barton, Arora, Thakur, Chiniga, Tatake, Pandey, Holkar, Holkar and Pond.

Algal bioplastics: current market trends and technical aspects.

Abstract: Plastics are undebatably a hot topic of discussion across international forums due to their huge ecological footprint. The onset of COVID-19 pandemic has exacerbated the issue in an irreversible manner. Bioplastics produced from renewable sources are a result of lookout for sustainable alternatives. Replacing a ton of synthetic plastics with biobased ones reduces 1.8 tons CO2 emissions. Here, we begin with highlighting the problem statement-Plastic accumulation and its associated negative impacts. Microalgae outperforms plants and microbes, when used to produce bioplastic due to superior growth rate, non-competitive nature to food, and simultaneous wastewater remediation. They have minimal nutrient requirements and less dependency on climatic conditions for cultivation. These are the reasons for current boom in the algal bioplastic market. However, it is still not at par in price with the petroleum-based plastics. A brief market research has been done to better evaluate the current global status and future scope of algal bioplastics. The objective of this review is to propose possible solutions to resolve the challenges in scale up of bioplastic industry. Various bioplastic production technologies have been comprehensively discussed along with their optimization strategies. Overall studies discussed show that in order to make it cost competitive adopting a multi-dimensional approach like algal biorefinery is the best way out. A holistic comparison of any bio-based alternative with its conventional counterpart is imperative to assess its impact upon commercialization. Therefore, the review concludes with the life cycle assessment of bioplastics and measures to improve their inclusivity in a circular economy.

Mechanism of Antiviral Activities of Nanoviricide's Platform Technology based Biopolymer (NV-CoV-2).

NV-CoV-2 is a nanoviricide that is covalently bonded with polyethylene glycol (PEG) and alkyl pendants. This molecular design is used to attack many strains of coronaviruses in a broad-spectrum manner. The ligand works by competitive inhibition and binds to the same site on the S-protein of SARS-CoV that attaches to the cognate cellular receptor, ACE2. This prevents SARS-CoV from binding and infecting the cell. NV-CoV-2 is designed to bind to the free virion particles at multiple points encapsulate the virus and disable its ability to infect the cells. The multi-point binding interaction, like a nano-velcro-tape, may lead to lipid-lipid fusion of the alkyl chains in the nanoviricide micelle with the lipid envelope of the virus. The virus becomes dismantled to a capsid form before the host immune system becomes involved. This putative mechanism is orthogonal to many other anti-coronavirus agents in development. Thus, it maybe possible to produce a stronger antiviral effect when combining NV-CoV-2 therapy with other anti-coronavirus therapies such as Remdesivir (RDV). NV-CoV-2 can encapsulate other antiviral compounds as well. In this study, RDV was encapsulated and protected from serum-mediated degradation in vivo. As a result, RDV was available for a longer period of time to interact with RNA polymerase and inhibit.

Antimicrobial activity of a nanocomposite film formed by bacterial nanocellulose and titanium dioxide

The development of materials with antimicrobial properties has increased, mainly driven by the pandemic caused by the new coronavirus SARS-CoV-2. Bacterial nanocellulose (CB) is a polysaccharide produced and secreted by certain genera of bacteria that have unique properties (high purity, biodegradability, biocompatibility, among others) for the development of new materials with special characteristics. Titanium dioxide (TiO2) is an inorganic compound industrially produced as a white and odorless powder, that intrinsically presents photo activity, high stability, and antimicrobial activity, this mainly after irradiation of ultraviolet (UV) light irradiation. Aiming to provide antimicrobial properties on nanocellulose films produced by Komagataeibacter sp., TiO2 nanoparticles were incorporated into the surface and pores of nanocellulose film discs. After, antimicrobial activity assays were carried out in a photochemical reactor to evaluate Escherichia call ATCC 8739 susceptibilities when in contact with the CB-TiO2 film discs after 15 minutes, followed by count of colony-forming units (CFU) on agar plate. Results showed an inhibition of E. coli growth of 98.5% when in contact with CB-TiO2 in the presence of UV-A and an inhibition of 68.0% in the absence of UV-A, indicating the potential use of the biocomposite for the creation of materials and surfaces with antimicrobial properties.

Antimicrobial sustainable biopolymers for biomedical plastics applications - an overview

The Covid-19 pandemic has increased the need for personal protective equipment (PPE), especially for medical personnel: face masks, full protective clothing, gloves and goggles. To date, they are usually made of thermoplastic polymers, such as polypropylene (PP). To reduce the risk of secondary infections it is essential to enhance the antimicrobial (especially antibacterial and antiviral) properties of the materials used in PPE. There are some attempts to modify materials by, for example, silver nanoparticles or zinc oxides. The increasing demand for personal protective equipment, mostly masks, leads to an increase of environmental problem of non-biodegradable wastes. Therefore some researches on use of safer for user's health sustainable antimicrobial and biodegradable biopolymer fibers, such as cellulose, starch, chitosan, poly(lactic acid) (PLA) or poly(glycolic acid) (PGA), have been done. These biopolymers and their properties are discussed in this article.

Development and Characterization of Polypropylene Waste from Personal Protective Equipment (PPE)-Derived Char-Filled Sugar Palm Starch Biocomposite Briquettes.

Slow pyrolysis using a batch reactor at 450 °C was applied to the polypropylene (PP) powder derived from Coronavirus Disease 2019 (COVID-19) isolation gown waste to yield char briquettes, using sugar palm starch (SPS) and a manual hydraulic press. These studies are significant because of reductions in plastic waste from the preparation of barbecue coal due to environmental sustainability. The results presented here include the physical, morphological, thermal, combustion, and mechanical properties of char when reinforced with various percentages of SPS loadings (0, 10, 20, 30, and 40%), which act as a matrix/binder to produce char/sugar palm starch (C/SPS) composites. The physical and morphological characteristics of C/SPS composites were determined using Fourier transform infrared (FTIR) and field emission scanning electron microscopy (FESEM). On the other hand, the thermal and combustion properties of the C/SPS briquettes were studied via thermogravimetric and bomb calorimeter analysis. The results show that the compressive strength of the briquettes increased as the SPS loading increased, whereas the higher heating values (HHV) reduced. The findings indicate that C-80/SPS-20 briquettes presented excellent combustion characteristics (1,761,430 J/g) with satisfactory mechanical strength (1.463 MPa) in the compression test. Thus, C-80/SPS-20 briquettes are the most suitable composites for domestic and commercial uses.

Enzymatic Protein Biopolymers as a Tool to Synthetize Eukaryotic Messenger Ribonucleic Acid (mRNA) with Uses in Vaccination, Immunotherapy and Nanotechnology.

Multi-subunit enzymes are protein biopolymers that are involved in many cellular processes. The enzyme that carries out the process of transcription of mRNAs is RNA polymerase II (RNAPII), which is a multi-subunit enzyme in eukaryotes. This protein biopolymer starts the transcription from specific sites and is positioned by transcription factors, which form a preinitiation complex (PIC) on gene promoters. To recognize and position the RNAPII and the transcription factors on the gene promoters are needed specific DNA sequences in the gene promoters, which are named promoter elements. Those gene promoter elements can vary and therefore several kinds of promoters exist, however, it appears that all promoters can use a similar pathway for PIC formation. Those pathways are discussed in this review. The in vitro transcribed mRNA can be used as vaccines to fight infectious diseases, e.g., in immunotherapy against cancer and in nanotechnology to deliver mRNA for a missing protein into the cell. We have outlined a procedure to produce an mRNA vaccine against the SARS-CoV-2 virus, which is the causing agent of the big pandemic, COVID-19, affecting human beings all over the world. The potential advantages of using eukaryotic RNAPII to synthetize large transcripts are outlined and discussed. In addition, we suggest a method to cap the mRNA at the 5' terminus by using enzymes, which might be more effective than cap analogs. Finally, we suggest the construction of a future multi-talented RNAPII, which would be able to synthetize large mRNA and cap them in the test tube.