Synthesis of novel nicotinamide susbstituted phthalocyanine and photodynamic antomicrobial chemotherapy evaluation potentiated by potassium iodide against the gram positive S. aureus and gram negative E. coli.

In the present work, we propose the synthesis of novel nicotinamide subsituted phthlocyanine photosensitizer (PS) and characterized by FTIR, UV-visible, H-NMR and MALDI Toff spectroscopy. Nicotinamide plays a vital rule in the central nervous system and its potential as a therapeutic for neurodegenerative disease. Nicotinamide substituted PS (3) efficiently produced ROS via type-1 process as measured by DCF assay. We observed that our PS after red light illumination (22 J/cm2) killed gram positive S. aureus upto 3 log reduction. Furher the addition of Potassium Iodide (100 mM) significantly potentiated PS at lower concentrations and enhanced the bacterial killing upto 6 log reduction against the S. aureus. We further found that the synergistic effect of PS and KI also eradicated the gram negative E. coli strain at lower concentraion of PS and found to killed E. coli upto 5 log reduction under the red light illumination at 22 J/cm2 of light dose. The conjugation of such biologically important form of vitamin B3 with PS would be a great addition and could pav the way for the novel photodynamic agent in the treatement of cancer and infectious diseases. A new symmetrical Nicotinamide tetrasubstituted zinc phthalocyanine (3) was synthesized. Upon addition of potassium Iodide with PS, the PS exhibited significant photodynamic activity with 5-6 logs reduction in bacterial load was achieved.

DNA physical interaction mediated b-lymphoma treatment offered by tetra benzimidazole-substituted zinc (ii) phthalocyanine derivative.

Role of heterocyclic compounds with nitrogen substitution in therapeutic frontiers is well established. The efforts made in this study are directed to dissect the biological significance of benzimidazole-substituted zinc phthalocyanine derivative. Its capacity to act as an anticancer agent against the 2 B-lymphoma cell lines (low-grade and high-grade malignancy) was found out by recording florescence using Alamar blue dye. Further cytotoxic effect at the DNA level was analyzed by performing agarose gel electrophoresis. Molecular docking studies made mechanistic details crystal clear by showing potential dual binding modes employed for interaction with DNA that include minor groove binding and intercalation between bases. This advocates this derivative as potential anticancer agent and deserves further rounds of mechanistic study for its final journey to serve as a marketed drug.

Development of tri-component antibacterial hybrid fibres for potential use in wound care.

OBJECTIVE: Tri-component antibacterial psyllium-alginate-chitosan fibres were developed and their properties were studied with reference to their application in health-care. METHOD: Psyllium was co-extruded with sodium alginate as a carrier into a coagulation bath containing calcium chloride and hydrolysed chitosan. Different concentrations of the hydrolysed chitosan were used and an in vitro assessment of antibacterial activity of the produced fibres was carried out against the known pathogens of Staphylococcus aureus and Escherichia coli. The effect of hydrolysed chitosan bath composition on physical and mechanical properties of produced fibres was also examined. RESULTS: Chitosan-containing fibres demonstrated a 70-130% thicker dry diameter than the control fibre (F1). The linear density of the fibre increased from 6.8 to 10 tex as the chitosan concentration increased from 10g/l to 30g/l (fibre type F1 to F4). With the addition of hydrolysed chitosan, distilled water absorption was increased while the saline and solution-A (0.83% w/v NaCl and 0.03% w/v CaCl2) absorption decreased. The percentage strain of hybrid fibres was lower than the control fibre due to the inclusion of hydrolysed chitosan. At lower viscosities of the hydrolysed chitosan bath, the fibres were much stiffer due to better penetration of the hydrolysed chitosan. Similarly, at lower viscosities, the tenacities of the hybrid fibres were higher than the control fibre. The hydrolysed chitosan-treated fibres were more effective against Staphylococcus aureus than the Escherichia coli, and the antibacterial activity increased with the decrease in viscosity of the hydrolysed chitosan bath. CONCLUSION: We developed novel PAC fibres. Antibacterial testing showed that hydrolysed chitosan was more effective against Gram-positive bacteria than Gram-negative bacteria.

Research upon Cu-Doping Contents in TiO2 Nanoparticles Incorporated onto Cellulose Nanofibers for Dye Removal and Self-Cleaning Applications.

Cu-doping contents in the TiO2 lattice structure were studied to show the effects on the crystal structure, morphology, and photocatalytic activity of TiO2 nanoparticles and thus composite cellulosic nanofibrous membranes. Pristine and copper-doped TiO2 nanoparticles were synthesized using the sol-gel technique, a wet chemical method with the advantages of low synthesizing temperature, uniform nanosize distribution, and purity. The as-synthesized semiconductor nanoparticles were first tested with the dye removal process and then impregnated onto electrospun cellulose nanofibers (CL nanofibers) to acquire modified nanofibers with self-cleaning properties. The as-prepared composite CL nanofibers consisting of doped and undoped TiO2 nanoparticles were characterized by various techniques, such as field emission scanning electron microscopy, transmission electron microscopy, UV-vis, X-ray diffraction, Fourier transform infrared spectroscopy, and tensile tests. The copper-doped TiO2 molar ratio in the nanocomposite was found to possess a pronounced impact on the dye removal and self-cleaning effects under the visible light spectrum, whereas TiO2 is highly effective under specific UV-light irradiation. Optical measurements and dye decomposition showed that the Cu-doped TiO2 nanocomposite was optimized at a 1% molar ratio by the copper-doping concentration regarding dye removal and self-cleaning applications under the visible light range.

Sustainable bioactive food packaging based on electrospun zein-polycaprolactone nanofibers integrated with aster yomena extract loaded halloysite nanotubes.

Compostable zein-polycaprolactone (PZ) electrospun nanofiber integrated with different concentrations of Aster yomena extract loaded halloysite nanotubes (A. yomena-HNT) as bioactive nanofibrous food packaging is reported. SEM micrographs reveal heterogeneous nanofibers. A. yomena extract used in the study showed weak antioxidant activity with AAI and TEAC values of 0.229 and 0.346. In vitro, release profile over 7 days of A. yomena indicates a controlled, sustained, and prolonged release. The prepared nanofibers were effective against both gram-positive and gram-negative bacteria. The prepared composite nanofibers were rendered biocompatible and nontoxic when subjected to WST-1 and LDH assay after incubating with NIH 3T3 mouse fibroblast cell line. PZ-15 nanofiber packaging showed the best postharvest quality preservation in Black mulberry fruits after 4 days of storage at 25 °C and 85 % Rh. Moreover, the in vitro decomposition test reveals that the fabricated nanofibers decompose in the soil and do not pose as a threat to the environment.

PVA/Inulin-Based Sustainable Films Reinforced with Pickering Emulsion of Niaouli Essential Oil for Potential Wound Healing Applications.

In this study, sustainable water-based films were produced via the solvent-casting method. Petroleum-free-based polyvinyl alcohol (PVA) and carbohydrate-based inulin (INL) were used as matrices. Vegetable-waste pumpkin powder was used in the study because of its sustainability and antibacterial properties. Pickering emulsions were prepared using ß-cyclodextrin. The influence of the different ratios of the ß-cyclodextrin/niaouli essential oil (ß-CD/NEO) inclusion complex (such as 1:1, 1:3, and 1:5) on the morphological (SEM), thermal (TGA), physical (FT-IR), wettability (contact angle), and mechanical (tensile test) characteristics of PVA/inulin films were investigated. Moreover, the antibacterial activities against the Gram (-) (Escherichia coli and Pseudomonas aeruginosa) and Gram (+) (Staphylococcus aureus) bacteria of the obtained films were studied. From the morphological analysis, good emulsion stability and porosity were obtained in the Pickering films with the highest oil content, while instability was observed in the Pickering films with the lowest concentration of oil content. Thermal and spectroscopic analysis indicated there was no significant difference between the Pickering emulsion films and neat films. With the addition of Pickering emulsions, the tensile stress values decreased from 7.3 ± 1.9 MPa to 3.3 ± 0.2. According to the antibacterial efficiency results, films containing pumpkin powder and Pickering emulsion films containing both pumpkin powder and a ratio of 1:1 (ß-CD/NEO) did not have an antibacterial effect, while Pickering emulsion films with a ratio of (ß-CD/NEO) 1:3 and 1:5 showed an antibacterial effect against Escherichia coli, with a zone diameter of 12 cm and 17 cm, respectively. Among the samples, the films with ratio of (ß-CD/NEO) 1:5 had the highest antioxidant capacity, as assessed by DPPH radical scavenging at 12 h intervals. Further, none of the samples showed any cytotoxic effects the according to LDH and WST-1 cytotoxicity analysis for the NIH3T3 cell line. Ultimately, it is expected that these films are completely bio-based and may be potential candidates for use in wound healing applications.

Synthesized bioactive lignin nanoparticles/polycaprolactone nanofibers: A novel nanobiocomposite for bone tissue engineering.

The use of artificial biomaterial with enhanced bioactivity for osteostimulation is a major research concern at present days. In this research, antibacterial and osteostimulative core-shell lignin nanoparticles (LgNP) were synthesized from alkali lignin using tetrahydrofuran (THF) as solvent via a simultaneous pH and solvent shifting technology. Later, LgNP-loaded polycaprolactone (PCL) composite nanofibers were fabricated via the electrospinning technique. The addition of LgNP significantly increased the diameter of the nanofibers, ranging from 400 to 2200 nm. The addition of LgNP reduced the mechanical performance, crystallinity, and porosity of the nanofibers while improving surface wetting and swelling properties of the inherently hydrophobic PCL polymer. The prepared nanofibers showed excellent bactericidal efficacy against major bone infectious Gram-positive Staphylococcus aureus bacterial strains. The incorporation of LgNP imparted superior antioxidant activity and boosted the biodegradation process of the nanofibers. The deposition of biomineral apatite with platelet-like clustered protrusions having a Ca/P ratio of 1.67 was observed while incubating the scaffold in simulated body fluid. Based on the results of the LDH and WST-1 assay, it was demonstrated that the composite nanofibers are non-toxic to pre-osteoblastic cell line (MC3T3-E1) when they are placed in direct contact with the LgNP/PCL scaffold nanofibers. The MC3T3-E1 cells exhibited excellent proliferation and attachment on the prepared composite scaffold via filopodial and lamellipodial expansion with cell-secreted Ca deposition. According to the alkaline phosphatase activity test, LgNP/PCL nanofiber scaffolds significantly improved osteogenic differentiation of MC3T3-E1 cells compared to neat PCL nanofibers. Overall, our findings suggest that LgNP/PCL nanofiber scaffold could be a promising functional biomaterial for bone tissue engineering.

Development of PVA-Psyllium Husk Meshes via Emulsion Electrospinning: Preparation, Characterization, and Antibacterial Activity.

In this study, polyvinyl alcohol (PVA) and psyllium husk (PSH)/D-limonene electrospun meshes were produced by emulsion electrospinning for use as substrates to prevent the growth of bacteria. D-limonene and modified microcrystalline cellulose (mMCC) were preferred as antibacterial agents. SEM micrographs showed that PVA-PSH electrospun mesh with a 4% amount of D-limonene has the best average fiber distribution with 298.38 ± 62.8 nm. Moreover, the fiber morphology disrupts with the addition of 6% D-limonene. FT-IR spectroscopy was used to analyze the chemical structure between matrix-antibacterial agents (mMCC and D-limonene). Although there were some partial physical interactions in the FT-IR spectrum, no chemical reactions were seen between the matrixes and the antibacterial agents. The thermal properties of the meshes were determined using thermal gravimetric analysis (TGA). The thermal stability of the samples increased with the addition of mMCC. Further, the PVA-PSH-mMCC mesh had the highest value of contact angle (81° ± 4.05). The antibacterial activity of functional meshes against Gram (-) (Escherichia coli, Pseudomonas aeruginosa) and Gram (+) bacteria (Staphylococcus aureus) was specified based on a zone inhibition test. PPMD6 meshes had the highest antibacterial results with 21 mm, 16 mm, and 15 mm against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, respectively. While increasing the amount of D-limonene enhanced the antibacterial activity, it significantly decreased the amount of release in cases of excess D-limonene amount. Due to good fiber morphology, the highest D-limonene release value (83.1%) was observed in PPMD4 functional meshes. The developed functional meshes can be utilized as wound dressing material based on our data.

Sabina chinensis leaf extracted and in situ incorporated polycaprolactone/polyvinylpyrrolidone electrospun microfibers for antibacterial application.

Sabina chinensis is a valuable reforestation conifer and traditional medicinal plant. In order to retain the physiological and pharmacological activities of the plant and obtain a fibrous material with better antibacterial properties, a mixed solvent of dichloromethane and N,N'-dimethylformamide was used to obtain the leaf extracts, and Sabina chinensis leaf extract (ScLE)-loaded PCL/PVP microfibers were successfully fabricated by electrospinning. The whole preparation process was carried out at room temperature to avoid deterioration of active ingredients. From the antibacterial activity test, it was observed that ScLE-loaded polycaprolactone/polyvinylpyrrolidone (PCL/PVP) microfibers had potential antibacterial activity against both Gram-positive and Gram-negative bacteria stains. The morphological properties of the prepared microfibers were observed by SEM. As the proportion of ScLE increased, the fiber diameter gradually increased and the surface was smooth. The excess ScLE addition caused the formation of beads during electrospinning. Considering different characterization results, 33% (v/v) addition of ScLE to the spinning solution was the optimum ratio. The winding structure obtained by the interaction of components in ScLE with PCL and PVP was confirmed by FTIR, XRD and WCA tests, which indicated that ScLE-loaded microfibers possessed excellent thermal stability, tear resistance and degradation resistance. It is expected that the prepared composite microfibers have potential applications as robust antibacterial meshes and films in the fields of biomedicine and air purification.

Polyvinylidene fluoride nanocomposite super hydrophilic membrane integrated with Polyaniline-Graphene oxide nano fillers for treatment of textile effluents.

Water pollution from the fashion industries containing dyes has become a major source of water pollution. These anthropogenic contaminated waters directly enter irrigation and drinking water systems, causing irreversible environmental damage to human health. Nanomembrane technology has attracted extensive attention to remove these toxic chemicals but new approaches are still required for improving removal efficiency and control the channel size. The work deals with the fabrication of a novel hybrid polyvinylidene fluoride (PVDF)-polyaniline (PANI) membrane with graphene oxide (GO). Incorporation of PANI-GO as a nanofiller has significantly improved antifouling properties and a solvent content of the fabricated membrane. Besides, pure water flux also increases from 112 to 454 L m-2 h-1 indicating the hydrophilic nature of the nanocomposite membrane. Among various compositions, the nanocomposites membrane with 0.1 %w/v GO demonstrated a maximum of 98 % dye rejection at 0.1 MPa operating pressure. After multiple testing of the membrane, the flux recovery ratio reached about 94 % and dyes rejection improved with the addition of PANI-GO. The removal efficiency of the composite membrane for Allura red is 98 % and for methyl orange is 95 %. Based on the above results the PVDF/PANI/GO membranes are recommended for practical use in wastewater treatment, particularly for anionic dyes removal from textile effluents.

Carboxymethyl Cellulose (CMC) Based Electrospun Composite Nanofiber Mats for Food Packaging.

Cellulose is one of the most abundantly available natural polymers. Carboxymethyl cellulose (CMC) belongs to the cellulose family and has different degrees of substitution. Current research comprises the fabrication and characterization of CMC nanofibers using polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) as capping agents and carriers for sustainable food packaging applications. Recently authors successfully fabricated smooth and uniform nanofibers of stated polymers and optimized the ratios of three polymers for continuous production. However, in this research, it was further characterized for mechanical properties, surface properties, structural properties, air permeability, and chemical properties to confirm the suitability and scope of tri-component nanofibrous mats in food packaging applications. Different fruits and vegetables were packed in a plastic container and closed by nanofiber mats and by a plastic lid. All samples were observed after a specific period of time (fruits were kept for 40 days while vegetables were kept for 10 days in the controlled environment). It was observed in the results that fruits and vegetables closed by nanofiber based webs exhibited better freshness and lower accumulation of moisture as compared to that of containers with plastic lids. From the results of performed tests, it was observed that nanofiber mats possess enough mechanical, structural, and morphological properties to be used as food packaging.

Lignin-mediated in-situ synthesis of CuO nanoparticles on cellulose nanofibers: A potential wound dressing material.

Herein we present our research on the synthesis of CuO nanoparticles on the surface of electrospun cellulose (CE) nanofibers using alkali lignin as a reducing agent. Fascinatingly, CA nanofibers were deacetalized during alkali lignin treatment, which was verified by FTIR-ATR spectra. The morphology of the produced nanofibers was observed with SEM and TEM. The presence of CuO nanoparticles was verified by EDX, XRD, and XPS. The Cu/CE nanofibers showed low thermal stability. MVTR values of 2100-1900 g/m2/day are adequate for the transport of air and moisture from the wound surface. The Cu/CE showed faster release (80%) of copper ions to aqueous environment within 24 h and seemed to advance towards plateau for the next five days. The Cu/CE nanofibrous mats exhibited excellent antibacterial efficacy against both gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus) bacteria. NIH3T3 fibroblast cells have excellent migrating and proliferating ability on our prepared nanofibrous mats. The presence of bound alkali lignin on the surface of nanofibers added a benefit of antioxidant activity. These findings revealed that such type of nanofibrous mats could be used as a potential wound dressing material.

Wet-spun bi-component alginate based hydrogel fibers: Development and in-vitro evaluation as a potential moist wound care dressing.

In this study, bi-component alginate-hyaluronic acid (AHA) fibers were developed by using two different routes. In the first method, sodium alginate dope solution was extruded into a coagulation bath containing CaCl2 and subsequently dip-coated with hyaluronic acid (HA) whereas, in the second method, hyaluronic acid-containing sodium alginate dope solution was directly extruded into CaCl2 bath. The resulting AHA fibers were then dehydrated in 25-100% v/v acetone solutions and dried in air. The fibers were characterized by surface morphology, physicochemical analysis, mechanical performance, swelling percentage, and total liquid absorption (g/g), cell viability, and release behavior. The results showed that AHA fibers produced by the second method have better mechanical performance, high liquid absorption, and swelling percentage with a more controlled release of hyaluronic acid. The AHA fibers showed high biocompatibility toward nHDF cell line in in-vitro testing, and the MVTR values (650-800 g/m2/day) are in a suitable range for maintaining a moist wound surface proving to be appropriate for promoting wound healing.

Evaluating Antibacterial Efficacy and Biocompatibility of PAN Nanofibers Loaded with Diclofenac Sodium Salt.

Side effects of the drugs' oral administration led us to examine the possibility of using diclofenac sodium (DLF) in a polymeric drug delivery system based on electrospun polyacrylonitrile (PAN) nanofibers, which can be produced cost-effectively and with good applicability for transdermal treatments. The inclusion of DLF in PAN nanofibers increased the nanofiber diameter from ~200 nm to ~500 nm. This increase can be attributed to the increase in the spinning solution viscosity. FTIR spectra confirm the entrapment of the DLF into the PAN nanofibers. X-ray diffraction pattern showed that the inclusion of the DLF in the PAN nanofibers had caused the misalignment in the polymeric chains of the PAN, thus resulting in a decrease of the peak intensity at 2θ = 17o. The DLF loaded PAN nanofibers were efficient against the gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli), with maximum inhibition zone of 16 ± 0.46 mm for E. coli and 15.5 ± 0.28 mm for S. aureus. Good cell viability ~95% for L929 cells in more extended incubation periods was reported. A gradual release of DLF from the PAN nanofiber was observed and can be attributed to the stability of Pan in PBS medium. Cell adhesion micrographs show that cell-cell interaction is stronger than the cell-material interaction. This type of weak cell interaction with the wound dressing is particularly advantageous, as this will not disturb the wound surface during the nursing of the wound.

Development of a Potent Antimicrobial Peptide With Photodynamic Activity.

The emergence of antibiotic-resistant bacteria poses a serious challenge to medical practice worldwide. A small peptide with sequence RWRWRW was previously identified as a core antimicrobial peptide with limited antimicrobial spectrum to bacteria, especially Gram-positive bacteria. By conjugating this peptide and its analogs with lipophilic phthalocyanine (Pc), we identified a new antibiotic peptide [PcG3K5(RW)3]. The peptide demonstrates increased antimicrobial effect to both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. In addition, Pc also provides added and potent antimicrobial effect upon red light illumination. The inhibitory efficacy of PcG3K5(RW)3 was increased by ~140-fold to nanomolar range upon illumination. Moreover, PcG3K5(RW)3 was safe for mammalian cell and promoted wound healing in the mouse infection model. Our work provides a new direction to optimize antimicrobial peptides to enhance antimicrobial efficacy.

Fabricating Antibacterial and Antioxidant Electrospun Hydrophilic Polyacrylonitrile Nanofibers Loaded with AgNPs by Lignin-Induced In-Situ Method.

Concerning the environmental hazards owing to the chemical-based synthesis of silver nanoparticles (AgNPs), this study aimed to investigate the possibility of synthesizing AgNPs on the surface polyacrylonitrile (PAN) nanofibers utilizing biomacromolecule lignin. SEM observations revealed that the average diameters of the produced nanofibers were slightly increased from ~512 nm to ~673 nm due to several factors like-swellings that happened during the salt treatment process, surface-bound lignin, and the presence of AgNPs. The presence of AgNPs was validated by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The amount of synthesized AgNPs on PAN nanofibers was found to be dependent on both precursor silver salt and reductant lignin concentration. Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectra confirm the presence of lignin on PAN nanofibers. Although the X-ray diffraction pattern did not show any AgNPs band, the reduced intensity of the stabilized PAN characteristics bands at 2θ = 17.28° and 29.38° demonstrated some misalignment of PAN polymeric chains. The water contact angle (WCA) of hydrophobic PAN nanofibers was reduced from 112.6 ± 4.16° to 21.4 ± 5.03° for the maximum AgNPs coated specimen. The prepared membranes exhibited low thermal stability and good swelling capacity up to 20.1 ± 0.92 g/g and 18.05 ± 0.68 g/g in distilled water and 0.9 wt% NaCl solution, respectively. Coated lignin imparts antioxidant activity up to 78.37 ± 0.12% at 12 h of incubation. The resultant nanofibrous membranes showed a proportional increase in antibacterial efficacy with the rise in AgNPs loading against both Gram-positive S. aureus and Gram-negative E. coli bacterial strains by disc diffusion test (AATCC 147-1998). Halos for maximum AgNPs loading was calculated to 18.89 ± 0.15 mm for S. aureus and 21.38 ± 0.17 mm for E. coli. An initial burst release of silver elements within 24 h was observed in the inductively coupled plasma-atomic emission spectrometry (ICP-AES) test, and the release amounts were proportionally expansive with the increase in Ag contents. Our results demonstrated that such types of composite nanofibers have a strong potential to be used in biomedicine.

Bioactive Sambong oil-loaded electrospun cellulose acetate nanofibers: Preparation, characterization, and in-vitro biocompatibility.

Blumea balsamifera oil loaded cellulose acetate nanofiber mats were prepared by electrospinning. The inclusion of blumea oil increased the nanofiber diameter. FTIR spectra confirm the addition of blumea oil in the nanofiber mats. The XRD pattern suggests that the inclusion of blumea oil has caused a misalignment in the polymer chains of the cellulose acetate. Thus, a decrease in the tensile strength was observed for the blumea oil loaded nanofibers. The increase in fiber diameter causes a reduction in the porosity of the nanofiber mats. The blumea oil loaded nanofiber mats showed antibacterial efficacy against Escherichia coli and Staphylococcus aureus. The blumea oil showed antioxidant abilities against the DPPH solution. MVTR of the neat and blumea oil loaded nanofiber mats was in the range of 2450-1750 g/m2/day, which is adequate for the transport of air and moisture from the wound surface. Blumea oil loaded mats showed good cell viability ~92% for NIH 3T3 cells in more extended periods of incubation. A biphasic release profile was obtained, and the release followed the first-order kinetics depending upon the highest value of the coefficient of correlation R 2 (88.6%).

A review on the fabrication of several carbohydrate polymers into nanofibrous structures using electrospinning for removal of metal ions and dyes.

Water contamination by heavy metals and dyes has been one of the most severe problems globally. Various techniques have been employed to remove these contaminants from water, including adsorption and photocatalysis, which are highly efficient and environmentally friendly approaches. The overuse of traditional petroleum-based plastics in the production of filtration systems aggravates the status quo due to negative impacts on the environment. Bio-based polysaccharide polymers with the green and benign features and potential for commercial applications have been employed as feasible alternatives to replace synthetic polymers and reduce environmental impacts. With unique chemical composition, molecular weights, and functional chemical groups such as hydroxyl, amine, and carboxyl groups, carbohydrate polymers show multitude potentials for dye and metal ion chelation. This review focused on the fabrication of carbohydrate polymers, such as chitosan, cellulose, alginate, pullulan, starch, and hyaluronic acid, into nanofibrous structures using the electrospinning method and their environmental applications.

Investigation of Mechanical, Chemical, and Antibacterial Properties of Electrospun Cellulose-Based Scaffolds Containing Orange Essential Oil and Silver Nanoparticles.

This study demonstrated a controllable release properties and synergistic antibacterial actions between orange essential oil (OEO) and silver nanoparticles (AgNPs) incorporated onto cellulose (CL) nanofibers. The preparation of AgNPs attached on CL nanofibers was conducted through multiple processes including the deacetylation process to transform cellulose acetate (CA) nanofibers to CL nanofibers, the in situ synthesis of AgNPs, and the coating of as-prepared silver composite CL nanofibers using OEO solutions with two different concentrations. The success of immobilization of AgNPs onto the surface of CL nanofibers and the incorporation of OEO into the polymer matrix was confirmed by SEM-EDS, TEM, XRD, and FT-IR characterizations. The tensile strength, elongation at break, and Young's modulus of the nanofibers after each step of treatment were recorded and compared to pristine CA nanofibers. The high antibacterial activities of AgNPs and OEO were assessed against Gram-positive B. subtilis and Gram-negative E. coli microorganisms. The combined effects of two antimicrobials, AgNPs and OEO, were distinctively recognized against E. coli.

Reusability Comparison of Melt-Blown vs Nanofiber Face Mask Filters for Use in the Coronavirus Pandemic.

Shortage of face masks is a current critical concern since the emergence of coronavirus-2 or SARS-CoV-2 (COVID-19). In this work, we compared the melt-blown (MB) filter, which is commonly used for the N95 face mask, with nanofiber (NF) filter, which is gradually used as an effective mask filter, to evaluate their reusability. Extensive characterizations were performed repeatedly to evaluate some performance parameters, which include filtration efficiency, airflow rate, and surface and morphological properties, after two types of cleaning treatments. In the first cleaning type, samples were dipped in 75% ethanol for a predetermined duration. In the second cleaning type, 75% ethanol was sprayed on samples. It was found that filtration efficiency of MB filter was significantly dropped after treatment with ethanol, while the NF filter exhibited consistent high filtration efficiency regardless of cleaning types. In addition, the NF filter showed better cytocompatibility than the MB filter, demonstrating its harmlessness on the human body. Regardless of ethanol treatments, surfaces of both filter types maintained hydrophobicity, which can sufficiently prevent wetting by moisture and saliva splash to prohibit not only pathogen transmission but also bacterial growth inside. On the basis of these comparative evaluations, the wider use of the NF filter for face mask applications is highly recommended, and it can be reused multiple times with robust filtration efficiency. It would be greatly helpful to solve the current shortage issue of face masks and significantly improve safety for front line fighters against coronavirus disease.