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Denim fabric samples representing current indigo dye sources and fabric structures were biodegraded in feedstock including food waste, manure, and animal bedding, which are typically composted at the Cornell Farm Services Composting Facility and processed under laboratory conditions for 77 days. Indigo types including dry denim, pre-reduced, and natural did not inhibit degradation as compared to undyed 100% cotton fabric. Additionally, fabrics tested as received from the mill and those tested post scouring degraded effectively. As expected, denim containing 24% polyester and 2% spandex retained overall fabric structure despite degradation of the cotton portion of the yarns. 

Various textiles have previously been evaluated for use in cloth face masks as a reusable option to help control the spread of respiratory viruses, but only their initial performance was tested. In this study, a broad range of fabrics (3 knit, 7 woven, and 3 nonwoven) were characterized for filtration efficiency (FE) and air permeability (AP) before and after 40 decontamination cycles by home laundry, microwave-generated steam, or dishwasher sterilization. AP was quantified following ASTM D737, and FE was assessed using NaCl aerosol in a simulated breathing system. While most fabrics maintained or improved their FE after 40 decontamination cycles, the AP of many fabrics decreased due to detergent buildup, fiber breakage, and fabric shrinkage. Tightly woven cotton fabrics had unacceptably low AP and FE performance. Knit and nonwoven structures had the best balance of properties, and although they are not recommended for use in single-layer masks, they have potential use in multilayer masks. 

As potential high surface area for selective capture in diagnostic or filtration devices, biotin-cellulose nanofiber membranes were fabricated to demonstrate the potential for specific and bio-orthogonal attachment of biomolecules onto nanofiber surfaces. Cellulose acetate was electrospun and substituted with alkyne groups in either a one- or two-step process. The alkyne reaction, confirmed by FTIR and Raman spectroscopy, was dependent on solvent ratio, time, and temperature. The two-step process maximized alkyne substitution in 10/90 volume per volume ratio (v/v) water to isopropanol at 50 °C after 6 h compared to the one-step process in 80/20 (v/v) at 50 °C after 48 h. Azide-biotin conjugate “clicked” with the alkyne-cellulose via copper-catalyzed alkyne-azide cycloaddition (CuAAC). The biotin-cellulose membranes, characterized by FTIR, SEM, Energy Dispersive X-ray spectroscopy (EDX), and XPS, were used in proof-of-concept assays (HABA (4′-hydroxyazobenzene-2-carboxylic acid) colorimetric assay and fluorescently tagged streptavidin assay) where streptavidin selectively bound to the pendant biotin. The click reaction was specific to alkyne-azide coupling and dependent on pH, ratio of ascorbic acid to copper sulfate, and time. Copper (II) reduction to copper (I) was successful without ascorbic acid, increasing the viability of the click conjugation with biomolecules. The surface-available biotin was dependent on storage medium and time: Decreasing with immersion in water and increasing with storage in air.