Effect of Cellulose Characteristics on the Properties of the Wet-Spun Aerogel Fibers

Abstract

Cellulose aerogels (CAs) from plant or bacterial-derived cellulose have advantages such as low density, high porosity, and high specific surface area and have been used in various applications including biomedical fields. One limiting factor in developing CAs is their demanding shaping process since it involves several steps of dissolution/dispersion of cellulose, geometry configurations using molds or nozzles, coagulation and washing of the gel body, and drying techniques. CA fibers can be converted into textiles and enhance the design ability, stiffness, and flexibility of the CAs. This study aims to understand the correlations between the initial cellulose characteristics, aerogel’s internal structure, and its prospective biomedical application. Wet-spun CA fibers were obtained by supercritical CO2 drying from low and high molecular weight microcrystalline cellulose in calcium thiocyanate tetrahydrate solution. Fiber spinning, thermal behavior, textural properties, and biological assessments of the CA fibers were inspected. The CA microfibers from high molecular weight cellulose proved to have a higher surface area (~197 m2/g), denser structure, and finer nanofibrils (~2 nm) with better thermal stability in comparison with the fibers produced from low molecular weight cellulose. The fibers were nontoxic, and cell proliferation was observed over time. CA fibers showed promising results to be used for biomedical applications such as tissue engineering and wound care.

Drug‐Eluting Medical Textiles: From Fiber Production and Textile Fabrication to Drug Loading and Delivery

“…Supercritical CO 2 (scCO 2 ) is a "tunable solvent" as its properties, such as viscosity, density, and diffusivity, can be controlled by varying pressure or temperature. [15,30,222,223] Furthermore, scCO 2 has an intermediate behavior between gas and liquid, possessing a density similar to that of the liquid, 0.2-1.5 g cm −3 , and transport properties close to those of the gas. In addition, scCO 2 is a dissolvable medium for nonpolar low molecular weight compounds; however, in case of poor solubility, a cosolvent like ethanol is used to increase the solubility of the polar molecules.…”

Drug loaded cellulose–chitosan aerogel microfibers for wound dressing applications

“…The fibers were collected in the coagulation bath on a porous stainless steel bobbin with a winding rate of 50 rpm. Fibers were washed in a customized soxhlet extractor system (NS 100) and the presence of salt leftovers was checked by conductivity meter and spot test as explained elsewhere (Rostamitabar et al 2021b).…”

“…Drug impregnation in the aerogel fibers can be performed either during gel preparation or during the network formation (solvent exchange) or after drying the aerogel through the post-treatment method which utilizes scCO 2 as a medium to dissolve and impregnate the drug (Ulker and Erkey 2014). In addition, producing microfiber aerogels not only can enhance the mechanical properties, stiffness, and shapeability of aerogels but also lead to short scCO 2 drying times and scalable production processes (Rostamitabar et al 2021b).…”

Drug‐Eluting Medical Textiles: From Fiber Production and Textile Fabrication to Drug Loading and Delivery

“…However, due to the low mechanical properties of aerogels in fibers, they have not been extensively investigated. [223,226] Drug loading in the aerogel fibers can be done either during gel preparation (Figure 5F-I), during the conventional sol-gel process, so-called solvent exchange (Figure 5F-II), [227] or during the post treatment of the synthesized gel (Figure 5F-III). [228] Post treatment loading has been extensively utilized for nonaerogel materials too.…”

“…Supercritical CO 2 (scCO 2 ) is a “tunable solvent” as its properties, such as viscosity, density, and diffusivity, can be controlled by varying pressure or temperature. [ 15,30,222,223 ] Furthermore, scCO 2 has an intermediate behavior between gas and liquid, possessing a density similar to that of the liquid, 0.2–1.5 g cm −3 , and transport properties close to those of the gas. In addition, scCO 2 is a dissolvable medium for nonpolar low molecular weight compounds; however, in case of poor solubility, a cosolvent like ethanol is used to increase the solubility of the polar molecules.…”