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Cotton fibers represent a sustainable and environmentally responsible raw material for the production of nonwoven textiles which are currently dominated by synthetic fibers derived from petrochemicals. Natural variation in quality parameters such as fineness, length, and strength present a challenge for cotton fiber conversion to yarns and in weaving and knitting for conventional textiles. The grading process for cotton fibers addresses this issue by allowing converters to select fibers suitable for specific woven textile applications. However, there has been little attempt to correlate cotton fiber quality traits with nonwoven textiles performance. This study examined the relationship of cotton fiber quality and fluid handling and moisture management performance properties of nonwoven textiles for personal hygiene and disposable applications. This includes potential end-use in diapers and incontinence products as well as disposable textiles for use in clinical settings. Ten recombinant inbred lines of cotton with a broad distribution of fiber quality traits were selected from a multiparent advanced generation intercross population. Fibers were harvested, converted into nonwoven textiles, and subjected to a series of standardized testing protocols. The results indicated that inferior quality coarse cotton fibers subjected to discount market pricing can be selectively utilized for nonwoven applications that benefit from improved moisture management and fluid handling performance. [ABSTRACT FROM AUTHOR]

Cotton fibers can be used to produce nonwovens suitable for numerous single use applications including hygiene, wipes, and medical products among others. Cotton comprises a relatively small amount of total raw materials used in nonwovens production compared to the synthetic fibers of polyester and polypropylene, but the use of cotton fibers in nonwovens continues to increase due to demand for disposable products containing natural, sustainable, and biodegradable materials. However, the relationship between cotton fiber classification measurements and nonwoven fabric physical and functional properties are not well characterized. A better understanding of the effects of cotton fiber properties on nonwovens fabric properties will facilitate fiber selection for specific end-use applications. In this study, cotton fibers with broad distributions of fiber quality measurements from 10 recombinant inbred lines of a multi parent advanced generation intercross multiparent advanced generation intercross population were harvested and processed in their greige state into hydroentangled nonwoven fabrics of two distinct basis weights. Tensile testing of lightweight nonwovens indicated fiber length and tensile strength at break were positively correlated with fabric strength, whereas micronaire (air permeability of a fiber bundle) was negatively correlated indicating finer fibers contributed to increased fabric strength. Increased strength of heavyweight fabrics was mainly correlated with higher fiber uniformity index. These results suggest that cotton fibers could be selectively sourced based on fiber quality for specific nonwoven applications and establishes alternative market opportunities for cotton fibers classified as inferior and subject to discount pricing in the woven textile market. [ABSTRACT FROM AUTHOR]

Textiles made from cotton fibers are flammable and thus often include flame retardant additives for consumer safety. Transgressive segregation in multi-parent populations facilitates new combinations of alleles of genes and can result in traits that are superior to those of any of the parents. A screen of 257 recombinant inbred lines from a multi-parent advanced generation intercross (MAGIC) population for naturally enhance flame retardance (FR) was conducted. All eleven parents, like all conventional white fiber cotton cultivars produce flammable fabric. MAGIC recombinant inbred lines (RILs) that produced fibers with significantly lower heat release capacities (HRC) as measured by microscale combustion calorimetry (MCC) were identified and the stability of the phenotypes of the outliers were confirmed when the RILs were grown at an additional location. Of the textiles fabricated from the five superior RILs, four exhibited the novel characteristic of inherent flame resistance. When exposed to open flame by standard 45° incline flammability testing, these four fabrics self-extinguished. To determine the genetic architecture of this novel trait, linkage, epistatic and multi-locus genome wide association studies (GWAS) were conducted with 473k SNPs identified by whole genome sequencing (WGS). Transcriptomes of developing fiber cells from select RILs were sequenced (RNAseq). Together, these data provide insight into the genetic mechanism of the unexpected emergence of flame-resistant cotton by transgressive segregation in a breeding program. The incorporation of this trait into global cotton germplasm by breeding has the potential to greatly reduce the costs and impacts of flame-retardant chemicals. [ABSTRACT FROM AUTHOR]

With increasingly frequent highly infectious global pandemics, the textile industry has responded by developing commercial fabric products by incorporating antibacterial metal oxide nanoparticles, particularly copper oxide in cleaning products and personal care items including antimicrobial wipes, hospital gowns and masks. Current methods use a surface adsorption method to functionalize nanomaterials to fibers. However, this results in poor durability and decreased antimicrobial activity after consecutive launderings. In this study, cuprous oxide nanoparticles with nanoflower morphology (Cu2O nanoflowers) are synthesized in situ within the cotton fiber under mild conditions and without added chemical reducing agents from a copper (II) precursor with an average maximal Feret diameter of 72.0 ± 51.8 nm and concentration of 17,489 ± 15 mg/kg. Analysis of the Cu2O NF-infused cotton fiber cross-section by transmission electron microscopy (TEM) confirmed the internal formation, and X-ray photoelectron spectroscopy (XPS) confirmed the copper (I) reduced oxidation state. An exponential correlation (R2 = 0.9979) between the UV-vis surface plasmon resonance (SPR) intensity at 320 nm of the Cu2O NFs and the concentration of copper in cotton was determined. The laundering durability of the Cu2O NF-cotton fabric was investigated, and the superior nanoparticle-leach resistance was observed, with the fabrics releasing only 19% of copper after 50 home laundering cycles. The internally immobilized Cu2O NFs within the cotton fiber exhibited continuing antibacterial activity (≥99.995%) against K. pneumoniae, E. coli and S. aureus), complete antifungal activity (100%) against A. niger and antiviral activity (≥90%) against Human coronavirus, strain 229E, even after 50 laundering cycles. [ABSTRACT FROM AUTHOR]

There is current interest in replacing petroleum-based additives in consumer paper products with abundantly available, renewable and sustainable biopolymers such as lignin-containing cellulose nanofibers (LCNFs) and cottonseed protein. This research characterized the performance of cottonseed protein isolate with/without LCNFs to increase the dry strength of filter paper. The application of 10% protein solution with 2% LCNFs as an additive improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Improvements in tensile modulus and tensile strength were greatest for samples containing larger amounts of lignin and a greater degree of polymerization than for those with less lignin from the same biomass sources. [ABSTRACT FROM AUTHOR]

Azo dyes are commonly used in textile color processing for their wide array of vibrant colors. However, in recent years these dyes have become of concern in wastewater management given their toxicity to humans and the environment. In the present work, researchers remediated water contaminated with azo dyes using silver nanoparticles (Ag NPs) intercalated within cotton fabric as a catalyst, for their enhanced durability and reusability, in a reductive degradation method. Three azo dyes—methyl orange (MO), Congo red (CR), and Chicago Sky Blue 6B (CSBB)—were investigated. The azo degradation was monitored by UV/vis spectroscopy, degradation capacity, and turnover frequency (TOF). The Ag NP–cotton catalyst exhibited excellent degradation capacity for the dyes, i.e., MO (96.4% in 30 min), CR (96.5% in 18.5 min), and CSBB (99.8% in 21 min), with TOFs of 0.046 min−1, 0.082 min−1, and 0.056 min−1, respectively, using a 400 mg loading of catalyst for 100 mL of 25 mg L−1 dye. To keep their high reusability while maintaining high catalytic efficiency of >95% degradation after 10 cycles, Ag NPs immobilized within cotton fabric have promising potential as eco-friendly bio-embedded catalysts. [ABSTRACT FROM AUTHOR]

The global burden of the SARS-CoV-2 pandemic is thought to result from a high viral transmission rate. Here, we consider mechanisms that influence host cell–virus binding between the SARS-CoV-2 spike glycoprotein (SPG) and the human angiotensin-converting enzyme 2 (ACE2) with a series of peptides designed to mimic key ACE2 hot spots through adopting a helical conformation analogous to the N-terminal α1 helix of ACE2, the region experimentally shown to bind to the SARS-CoV-2 receptor-binding domain (RBD). The approach examines putative structure/function relations by assessing SPG binding affinity with surface plasmon resonance (SPR). A cyclic peptide (c[KFNHEAEDLFEKLM]) was characterized in an α-helical conformation with micromolar affinity (KD = 500 µM) to the SPG. Thus, stabilizing the helical structure of the 14-mer through cyclization improves binding to SPG by an order of magnitude. In addition, end-group peptide analog modifications and residue substitutions mediate SPG binding, with net charge playing an apparent role. Therefore, we surveyed reported viral variants, and a correlation of increased positive charge with increased virulence lends support to the hypothesis that charge is relevant to enhanced viral fusion. Overall, the structure/function relationship informs the importance of conformation and charge for virus-binding analog design. [ABSTRACT FROM AUTHOR]

Peptide–cellulose conjugates designed for use as optical protease sensors have gained interest for point-of-care (POC) detection. Elevated serine protease levels are often found in patients with chronic illnesses, necessitating optimal biosensor design for POC assessment. Nanocellulose provides a platform for protease sensors as a transducer surface, and the employment of nanocellulose in this capacity combines its biocompatibility and high specific surface area properties to confer sensitive detection of dilute biomarkers. However, a basic understanding of the spatiotemporal relationships of the transducer surface and sensor disposition is needed to improve protease sensor design and development. Here, we examine a tripeptide, fluorogenic elastase biosensor attached to TEMPO-oxidized nanofibrillated cellulose via a polyethylene glycol linker. The synthetic conjugate was found to be active in the presence of human neutrophil elastase at levels comparable to other cellulose-based biosensors. Computational models examined the relationship of the sensor molecule to the transducer surface. The results illustrate differences in two crystallite transducer surfaces ((110) vs. (1−10)) and reveal preferred orientations of the sensor. Finally, a determination of the relative (110) vs. (1−10) orientations of crystals extracted from cotton demonstrates a preference for the (1−10) conformer. This model study potentiates the HNE sensor results for enhanced sensor activity design. [ABSTRACT FROM AUTHOR]

To produce textiles that regenerate antimicrobial surfaces wash after wash, we synthesized and immobilized antimicrobial silver nanoparticles (Ag NPs) within brown cotton fibers. This composite formation is based on utilizing brown cotton fiber as a nanoreactornatural condensed tannins reduce Ag ions, and the swollen microfibrillar structure controls and stabilizes particle growth. A simple one-step process involving heating brown cotton in an aqueous solution of Ag ions actuates the self-synthesis of Ag NPs. Transmission electron microscopy (TEM) images of the fiber cross-section confirm the formation of Ag NPs (diameter of 8–21 nm, weight fraction of 12 800 mg/kg) throughout the entire volume of the fiber with a unique size distribution. The Ag NPs present within the cotton fiber were found to be leach-resistant against typical textile wet processing and prolonged laundering while serving as a reservoir of Ag ions. After 50 laundering cycles, cotton retains approximately 85% of the total Ag embedded and persistently inhibits 99.99% of both Gram-positive and Gram-negative bacteria. The fabrication of true cotton nanocomposite fibers holds promise for binder-free and permanent functionalization. [ABSTRACT FROM AUTHOR]

Arboviral diseases and malaria transmitted by mosquitoes are major health concerns worldwide responsible for millions of deaths annually. Spatial repellents have been used as preventative measures via direct application to the skin or disposable devices worn outside of clothing. Naturally derived, plant-based repellents are safe, effective alternatives to synthetic repellents and may be applied to disposable substrates including adhesive patches. Many disposables are composed of synthetic petrochemical-based polyester and polypropylene nonwoven fabrics, contributing to growing concern surrounding microplastic pollution. Sustainable and biodegradable substrates including those made from cotton are cost effective and environmentally friendly. Therefore, we explored the utilization of cotton-based substrates for the application of natural spatial and synthetic contact insect repellents. Cotton fibers used in the study were commercially available greige cotton, scoured and bleached greige cotton and reginned greige cotton motes, a value-added byproduct of the ginning process. Synthetic polyester and polypropylene were used for comparison. Thermogravimetric/derivative thermogravimetric analysis (TG/DTG) in combination with modulated differential scanning calorimetry (mDSC) were used to discern vaporization properties of repellents from the substrates. Retention times of repellents on the substrates were analyzed using a Fourier-transform infrared spectroscopy–focal plane array detector and compared with the TG/DTG and mDSC data. Mosquito landing assays confirmed the feasibility of using cotton-based substrates treated with plant-based spatial repellents as an effective and environmentally friendly alternative to synthetic materials. [ABSTRACT FROM AUTHOR]

A study was conducted on a commercial grade hydroentanglement system to assess the effects of jet strip configuration in terms of both orifice diameter (0.10 mm, 0.12 mm, and 0.14 mm) as well as the number of orifices per inch (40 and 50) on the properties of resultant nonwoven cotton fabrics at various hydroentanglement pressures (0, 5.0, 7.5, 10.0, 12.5, and 14.0 MPa). It was found that an increase in the energy applied to the fabric web resulted in a nonwoven with increased absorbency. The results of air permeability testing indicate that a combination of variations in the orifice diameter and the number of orifices per inch as well as the energy applied determine the overall air permeability of the fabric. Tensile testing revealed that increasing the energy applied to the fabric resulted in increased strength in both the machine and cross directions and decreased elongations. These results indicate that the mechanical and performance characteristics of nonwoven cotton fabrics produced by hydroentanglement may be manipulated to obtain the desired characteristics for the targeted end-use application. [ABSTRACT FROM AUTHOR]

Several nonwoven materials were evaluated as candidates for wipe fabrics intended for sensitive applications, namely aviation maintenance. Wipes designed for this purpose must conform to specific guidelines delineated by the appropriate governing bodies. Fabric selections included both synthetic and natural staple fibers such as polyester, Lyocell and raw cotton varieties. A thorough evaluation of extractable material in an array of solvents revealed that cotton-based nonwovens as well as Lyocell have some of the lowest percentages of leachable solids. The resistance of these fabrics to abrasion and the damage incurred by them was also studied. Environmental scanning electron microscopy taken before and after the linting procedure showed that the greige cotton sample demonstrated some of the least damage. Fourier-transform infrared spectroscopy examinations of hexane extracts confirmed the absence of any silicone grease contamination on the wipes materials. Standardized tensile testing indicated that the cotton samples, especially mechanically cleaned greige cotton, have robust tensile properties that are important characteristics for wiping materials. These results indicate that cotton nonwovens, particularly greige cotton, are promising candidates for the development of future aviation and other wipes materials. [ABSTRACT FROM AUTHOR]

A study was conducted on a commercial grade hydroentanglement system to assess the effects of jet strip configuration in terms of both orifice diameter (0.10 mm, 0.12 mm, and 0.14 mm) as well as the number of orifices per inch (40 and 50) on the properties of resultant nonwoven cotton fabrics at various hydroentanglement pressures (0, 5.0, 7.5, 10.0, 12.5, and 14.0 MPa). It was found that an increase in the energy applied to the fabric web resulted in a nonwoven with increased absorbency. The results of air permeability testing indicate that a combination of variations in the orifice diameter and the number of orifices per inch as well as the energy applied determine the overall air permeability of the fabric. Tensile testing revealed that increasing the energy applied to the fabric resulted in increased strength in both the machine and cross directions and decreased elongations. These results indicate that the mechanical and performance characteristics of nonwoven cotton fabrics produced by hydroentanglement may be manipulated to obtain the desired characteristics for the targeted end-use application. [ABSTRACT FROM AUTHOR]

Greige cotton (unbleached cotton) is an intact plant fiber that retains much of the outer cotton fiber layers. These layers contain pectin, peroxidases, and trace metals that are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. When greige cotton is subjected to a nonwoven hydroentanglement process, components of the outer cotton fiber layers are retained. When hydrated, this fabric can generate H2O2 (5-50 micromolar). This range has been characterized as inducing accelerated wound healing associated with enhanced cell signaling and the proliferation of cells vital to wound restoration. On the other hand, H2O2 levels above 50 micromolar have been associated with bacteriostatic activity. Here, we report the preparation and hydrogen peroxide activity of copper/ascorbate formulations, both as adsorbed and in situ synthesized analogs on cotton. The cooper/ascorbate-cotton formulations were designed with the goal of modulating hydrogen peroxide levels within functional ranges beneficial to wound healing. The cotton/copper formulation analogs were prepared on nonwoven unbleached cotton and characterized with cotton impregnation titers of 3-14 mg copper per gram of cotton. The copper/ascorbate cotton analog formulations were characterized spectroscopically, and the copper titer was quantified with ICP analysis and probed for peroxide production through assessment with Amplex Red. All analogs demonstrated antibacterial activity. Notably, the treatment of unbleached cotton with low levels of ascorbate (~2 mg/g cotton) resulted in a 99 percent reduction in Klebsiella pneumoniae and Staphylococcus aureus. In situ synthesized copper/ascorbate nanoparticles retained activity and did not leach out upon prolonged suspension in an aqueous environment. An assessment of H2O2 effects on fibroblast proliferation are discussed in light of the copper/cotton analogs and wound healing. [ABSTRACT FROM AUTHOR]

Nanocellulose has high specific surface area, hydration properties, and ease of derivatization to prepare protease sensors. A Human Neutrophil Elastase sensor designed with a nanocellulose aerogel transducer surface derived from cotton is compared with cotton filter paper, and nanocrystalline cellulose versions of the sensor. X-ray crystallography was employed along with Michaelis-Menten enzyme kinetics, and circular dichroism to contrast the structure/function relations of the peptide-cellulose conjugate conformation to enzyme/substrate binding and turnover rates. The nanocellulosic aerogel was found to have a cellulose II structure. The spatiotemporal relation of crystallite surface to peptide-cellulose conformation is discussed in light of observed enzyme kinetics. A higher substrate binding affinity (Km) of elastase was observed with the nanocellulose aerogel and nanocrystalline peptide-cellulose conjugates than with the solution-based elastase substrate. An increased Km observed for the nanocellulosic aerogel sensor yields a higher enzyme efficiency (kcat/Km), attributable to binding of the serine protease to the negatively charged cellulose surface. The effect of crystallite size and β-turn peptide conformation are related to the peptide-cellulose kinetics. Models demonstrating the orientation of cellulose to peptide O6-hydroxymethyl rotamers of the conjugates at the surface of the cellulose crystal suggest the relative accessibility of the peptide-cellulose conjugates for enzyme active site binding. [ABSTRACT FROM AUTHOR]