Establishing a 3D In Vitro Hepatic Model Mimicking Physiologically Relevant to In Vivo State

Three-dimensional (3D) bioprinting is a promising technology to establish a 3D in vitro hepatic model that holds great potential in toxicological evaluation. However, in current hepatic models, the central area suffers from hypoxic conditions, resulting in slow and weak metabolism of drugs and toxins. It remains challenging to predict accurate drug effects in current bioprinted hepatic models. Here, we constructed a hexagonal bioprinted hepatic construct and incorporated a spinning condition with continuous media stimuli. Under spinning conditions, HepG2 cells in the bioprinted hepatic construct exhibited enhanced proliferation capacity and functionality compared to those under static conditions. Additionally, the number of spheroids that play a role in boosting drug-induced signals and responses increased in the bioprinted hepatic constructs cultured under spinning conditions. Moreover, HepG2 cells under spinning conditions exhibited intensive TGFβ-induced epithelial-to-mesenchymal transition (EMT) and increased susceptibility to acetaminophen (APAP)-induced hepatotoxicity as well as hepatotoxicity prevention by administration of N-acetylcysteine (NAC). Taken together, the results of our study demonstrate that the spinning condition employed during the generation of bioprinted hepatic constructs enables the recapitulation of liver injury and repair phenomena in particular. This simple but effective culture strategy facilitates bioprinted hepatic constructs to improve in vitro modeling for drug effect evaluation.

Improvement of color value of bio-based polyamide 56 fibers

This paper introduces a feasible method to improve the color value of bio-based polyamide 56 (PA56) fiber. Three types of whitening modifiers were introduced into the bio-based PA56 fibers by the in-situ polymerization method and melt blending method in order to improve the fiber color. The color values and mechanical properties of PA56 fibers were tested and analyzed and the optimum additive ratio and process conditions were discussed. The results show that the improved color value of bio-based PA56 fibers can be achieved by the melt blending method of fluorescent whitening masterbatch and reasonable spinning condition control. When the additive amount of fluorescent whitening agent is 0.3%, the index of lightness (L) increased from 84 to 90, while the yellow index (YI) reduced from 16.8 to 12.6. Moreover, PA56 fibers show high breaking strength about 4.27 cN/dtex and good yellowing resistance and durability.

Influence of Spindle Air Pressure and its Direction on the Quality Characteristics of Polyester/Cotton Vortex Yarn

The influence of spindle air pressure and its direction on the properties of Polyester/Cotton vortex yarn was studied. The spindle air pressure direction was changed in both Z and S directions on the Z twist yarn of Ne 40s Polyester/Cotton vortex yarn (50:50 polyester: cotton) and these yarns were then tested for their properties such as tensile, unevenness, and hairiness. It was found that unevenness was lower with normal spinning condition and increased when the spindle air pressure increased in both directions. Imperfections were also found to be minimum with normal spinning condition and increased with increase in spindle air pressure. The yarn tenacity and elongation at break found to be lower at normal spinning condition. When the spindle air pressure increased yarn tenacity and elongation at break also increased with increase in spindle air pressure. At the same time spindle air pressure in the same direction of basic yarn twist gave less increase in tenacity and elongation than opposite direction of basic yarn twist. Hairiness index, H and hairiness in different length classes continuously increased as the spindle air pressure increased in opposite direction of basic yarn twist.

Optimal spinneret size for improvement of fiber's mechanical property

The effect of spinneret size and place on diameter and tensile property of cellulose acetate fibers is studied, and a criterion for the maximal breaking energy is obtained, and the spinneret distribution can be optimized for each spinning condition.

Preparation and Properties of Nano-Silica/calcium Alginate Blend Fibers

Calcium alginate fibers and nano-silica/calcium alginate blend fibers were prepared by the mean of wet spinning at the same spinning condition. The effect of nano-particles SiO2 on the structure and properties of alginate fibers were studied via many tests. The results showed that the tenacity of blend fibers increased with the growth of the content of SiO2 ranging from 1% to 5%, however, the tenacity of fibers became worse when the content of SiO2 was more than 5%. The effect of SiO2 content on hardness and tribological properties of the calcium alginate fiber was studied. The morphologies of the fibers surfaces were examined with a Scanning Electron Microscope (SEM). The result showed that the surface of blend fibers was still smooth when the consent of SiO2 not up to 7%, the best surface was obtained when SiO2 content was 5%. The incorporation of SiO2 also affected the absorption property of alginate fiber and made it decrease with the increase of SiO2 content. The structures of calcium alginate fibers and nano-silica/calcium alginate blend fibers were studied by infrared spectrum.