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In this work, the PVA-chitosan composite packaging films doped with biomass-fabricated zinc oxide nanoparticles (ZnO NPs) and dragon fruit waste extract (DFE) were developed for potential use in food packaging applications. ZnO NPs were synthesized using a sustainable method employing C. sinensis waste extract as a reducing agent. Chitosan and PVA were blended in a specific ratio (1: 1 w/w) to obtain a film-forming solution, into which the ZnO NPs and dragon fruit waste extract were incorporated. The resulting solution was cast into films, which were characterized using various analytical techniques. Mechanical properties, water solubility, and thermal stability of the films were also evaluated. The results demonstrated that the incorporation of green ZnO NPs and dragon fruit waste extract enhanced the mechanical strength and thermal stability of the films while reducing water vapor permeability. Moreover, the films exhibited biocidal and excellent 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging properties, indicating their use in the food packaging sector. The production of these films offers a practical approach to produce bioactive food packaging materials. The use of plant extract and waste material as reducing agents can reduce the overall cost of production while providing added benefits, such as antioxidant and antibacterial properties.

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Green finishing formulations have established an important place in textile dyeing and finishing industry. The use of plant extracts along with chemical metallic mordants is reported to increase colour values and improve fastness properties. However, metal salts as mordants constantly pose environmental and human health risks. The purpose of this work is to examine and extend the knowledge of natural dyeing technology considering the use of biological macromolecule chitosan (CS) to increase dye uptake, fastness and impart functional properties. The cotton was pre-coated with chitosan using pad-dry method and optimal chitosan concentrations were selected by evaluating the colour spectrometry data in term of CIEL*a*b* values. The chemical nature of the extract was characterized by UV-Vis, Fourier-transform infrared spectroscopy (FT-IR) and Thermogravimetric analysis (TGA) whereas dyed samples were analysed by Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) with mapping analysis, FT-IR, and TGA. Results showed that the aqueous extract of Citrus sinensis peel yielded interestingly shades all lying in yellow- red quadrant of CIELa*b* colour space with acceptable grades of wash and dry-wet fastness properties. This study reveals important information to understand synergism between two natural products in imparting semi durable antioxidant and antibacterial activity against E. coli and S. aureus, and thus offers full potential to be used in natural dyeing technology.

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Herein, a highly efficient multifunctional cotton fabric was developed based on a greener approach involving one step in-situ generation of silver nanoparticles (AgNPs) onto chitosan coated cotton (CS-cotton) by employing peanut waste shell extract (PSE) as an eco-friendly reducing agent. Major characteristics of the so prepared in-situ AgNPs@ chitosan-cotton viz size distribution of the particles, surface morphology, binding interaction were analysed by TEM-DLS, SEM, EDX-mapping, and FT-IR techniques. Colour spectrometry was used to measure colour parameters in terms of CIELa*b* values in order to realize the dyeing properties of silver nanoparticles onto chitosan coated cotton. The AgNPs deposited finished cotton samples were evaluated for antioxidant activity using 2, 2'-diphenyl-1-picrylhydrazyl radical (DPPH) assay, and antimicrobial tests were carried out using colony counting method against E. coli and S. aureus pathogens. Based on the obtained data, it was concluded that in-situ synthesis of AgNPs using peanut shell extract biomolecules produce cellulosic fabric with beautiful pale to deep yellowish hues, good antioxidant and excellent antibacterial properties. The tentative mechanism of AgNPs formation onto chitosan coated cotton was also reported.

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Nano-toxicological evaluation of a biomaterial is of primordial importance for application in therapeutics. This is one of first reports on systematic analysis of in vitro and in vivo cytocompatible properties of an antimicrobial polyethylene/silver-clay hybrid nanocomposite. The polymeric nanocomposite has been prepared using melt compounding route by a twin screw extruder with silver-clay hybrid content varying from 1 to 5 wt%. The morphology of the polyethylene/silver-clay nanocomposites was investigated using a combination of TEM and XRD techniques. The antimicrobial studies suggest strong biocidal action against E. coli, S. aureus and A. niger. In vitro cytocompatibility studies show excellent compatibility with human erythrocytes and dermal fibroblast cell lines, as compared to powder form silver-clay hybrids which demonstrated mild toxicity. Histopathological analysis of skin tissues excised from rats surgically stitched with nanocomposite film show no morphological change following 21 days of exposure. The developed nanocomposites show excellent antimicrobial activity coupled with cytocompatibility and are hence potential candidates for biomedical applications.

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Green chemistry mediated synthesis of nanoparticles is becoming an emerging area of research due to the environmental issues associated with toxic reagents involved in conventional synthesis. In this work, we present a straightforward and rapid green chemistry-based method to fabricate chitosan-based silver nanoparticles onto linen fabric in the presence of pineapple crown extract biomolecules such as sucrose, fructose and glucose. The resultant nanoparticles were studied by UV-vis, TEM, EDX, and their coating onto linen was supported by results from Scanning electron microscopy, EDX with mapping images, FTIR spectroscopy and TGA technique. This one step process yields spherical particles that are well dispersed and non-aggregated. Using chitosan polysaccharide, the colouring, antibacterial and radical scavenging activity of Ag nanoparticles (NPs) could be transferred to the linen fabric surface. Chitosan not only favours coating and stabilization of the silver ions, but synergistically with silver nanoparticles also exhibited strong antibacterial and antioxidant effects onto linen surface. The colouring properties of coated linen fabrics were measured in terms of CIELa*b* values using reflectance spectroscopy. The coated linen was also screened for their antibacterial activity against E. coli and S. aureus, while as antioxidant activity was investigated photometrically by DPPH assay. The results demonstrate that chitosan­silver nanoparticles can be used as safer and greener alternative to chemical functional agents currently being practiced.

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A comparative study on the antimicrobial behavior of high density polyethylene (HDPE) nanocomposite monofilaments based on three types of metal nanoparticles (NPs) decorated montmorillonite (MMT) has been presented. Modified MMT decorated with silver, copper and zinc oxide nanoparticles were synthesized in-lab and used as a reinforcing agent in preparing HDPE/modified MMT nanocomposite monofilaments via melt compounding and fiber spinning route in presence of compatibilizer. The concentration of modified MMT was varied from 1 to 5 wt. % in the nanocomposite monofilament. A mixture of intercalated and exfoliated morphology was observed from TEM and WAXD analyses with absence of clay agglomerations. DSC studies indicated MMT acting as heterogeneous nucleating agent with increased degree of crystallinity, crystallization temperature and rate of crystallization. The HDPE/modified MMT nanocomposite monofilaments showed remarkable decrease in bacterial colonies against Gram (-) E. coli and Gram (+) S. aureus with HDPE/Ag-MMT monofilaments showing the highest activity (>99%). The dissolution kinetics of metal ions/NPs from modified MMT nanostructure was studied to understand its effect on antimicrobial action. The antimicrobial filaments are potential candidates to replace neat HDPE counterparts in moist environment applications such as ropes, sacks, agricultural items and geotextiles where microbial growth is a cause of concern.

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Over the past few years, the application of green and sustainable biological macromolecules to replace petrochemical based agents for functional modification of textiles is gaining popularity worldwide. With a view to develop the green finishing process for linen fabrics, the present study was designed to evaluate colorimetric analysis and radical-scavenging activity of pineapple peel dyeing on linen pre-treated with chitosan polysaccharide under optimum natural dyeing conditions. Linen fabric was treated with different concentrations of chitosan using a conventional pad-dry-cure method. UV-vis was used to observe optical property of pineapple dye, while as Scanning electron microscopy, EDX analysis along with mapping images, Fourier transform infra-red spectroscopy, X ray diffraction, and thermal analysis of coated samples revealed the fixation of the chitosan onto the fabric's surface. Direct natural dyeing was compared with those obtained with chitosan coating. It was found that the pre-treatment of chitosan provided a significant improvement in dye uptake and CIELa*b* values. Furthermore, the linen fabric treated with chitosan in conjugation with pineapple natural dye showed excellent radical-scavenging properties compared to the control dyed linen. The depth of shade as well as radical-scavenging activity was found greatly dependent on chitosan concentration. The radical scavenging property was quite durable and was retained through 5 washing cycles. The analysis of the dyeing mechanism suggested that chitosan reacts with hydroxyl groups in cellulose and functional sites in natural dye via inter-ionic attractions.

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Chitosan is partially or completely N-deacetylated derivative of chitin and is chemically composed of ß­(1, 4) linked 2­amino­2­deoxy­ß­d­glucopyranose. Biocompatibility, non-toxicity, antifungal activity, water-binding capacity, bioactivity and antimicrobial properties make chitosan particularly attractive substitute for synthetic polymers in different application fields and notably in the textile industry. The presence of reactive amino and hydroxyl groups along the backbone conifer chitosan some interesting properties for use in textile dyeing and finishing. However, the main barrier to the use of chitosan is the lack of water solubility at neutral pH and poor durability on textile surfaces. To overcome this, chitosan has been chemically modified in several ways to obtain a wide range of important derivatives with a broad range of applications. This review is intended to provide a recent overview of chitosan and its derivatives and highlight their role in the development of antimicrobial textiles.

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With increasing demand for novel and potent antimicrobial agents to combat cross-infections and infectious diseases, silver and copper based nanoparticles (NPs) deposited over supports such as montmorillonite (MMT) are playing a crucial role in shaping the current research scenario. Although materials based on Ag NP and Cu NP on MMT have been reported, its toxicological properties on human cell lines have not been accounted for. This paper reports a comparative study on synthesis, antibacterial, antifungal and toxicological behavior of Ag and Cu NPs deposited over MMT nanosheets synthesized by employment of different reduction media. The effect of synthesized NP-MMT hybrids on human erythrocytes and fibroblast cells has been evaluated. The NP formation was facilitated using borohydride and ethyl alcohol (wet chemical route) and photo-reduction and thermal treatment (physical reduction route). The NP-MMT hybrids showed NP formation over supporting silicate layers with particle size ~10-50 nm confirmed by TEM micrographs and loading of ~6-22 wt% of metallic element by EDX analysis. The MMT layers were peeled apart to accommodate NPs inside its galleries, confirmed by increased d-value in powder WAXD. The NP-hybrids showed excellent inhibition zone against bacteria E.coli and S. aureus and fungi A. niger. RBC hemolysis and cytocompatibility assay were performed in vitro to advocate its safety to live human cells. These hybrid materials are potential candidates for new generation advanced antimicrobial materials with less toxicity and highly potent behavior.

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Chitosan is a potential renewable, versatile amino polysaccharide which has been approved by food and drug administration for use in food, cosmetics, pharmaceuticals and other industries. In order to determine if chitosan can be utilized in the development of colourful and multifunctional wool fabric without the need of toxic metal salt mordants, we have investigated the colouring, radical scavenging and antibacterial activity of wool dyed with tea extract polyphenols using chitosan as a green pre-treatment finishing agent. UV-vis analysis confirmed the optical properties of tea polyphenols, while Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and Thermogravimetric analysis (TGA) spectroscopic characterizations demonstrated binding, surface morphology and thermal stability properties of chitosan coated wool. Colour spectrometry data obtained in terms of CIEL*a*b* values showed an outstanding effect of the chitosan pre-treatment. The Camellia sinensis (tea) extract dyed wool yielded interestingly elegant pale to golden yellowish colours with acceptable wash fastness properties. The chitosan gets its affinity for the wool via hydrogen bonding, electrostatic and van der Waals interactions. The results also showed that chitosan pre-treatment imparts excellent radical scavenging and antibacterial activity against E. coli and S. aureus, and thus offers new opportunities in the realm of natural dyeing.

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This paper is a review of the latest developments in the field of topical drug delivery via which the drug is directly applied onto the skin with high selectivity and efficiency. Advances in microfiber-based medical textiles such as sutures and wound dressings, especially those containing a drug or an antimicrobial agent, have been covered briefly. A special focus is on recent developments in the area of nanofibrous drug delivery systems, which have several advantages due to their large surface area to volume ratio, high porosity and flexibility. The electrospinning technique to produce nanofibers has also been discussed with reference to latest advances such as multiple needles, needleless and coaxial forms of electrospinning. The applications of nanofibers in different areas such as wound dressing, periodontal and anticancer treatment have also been discussed.

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