Application of Bombyx mori Silk Fibroin Films for Liquid-Crystal Devices

Resistance to Degradation of Silk Fibroin Hydrogels Exposed to Neuroinflammatory Environments

Central nervous system (CNS) diseases represent an extreme burden with significant social and economic costs. A common link in most brain pathologies is the appearance of inflammatory components that can jeopardize the stability of the implanted biomaterials and the effectiveness of therapies. Different silk fibroin scaffolds have been used in applications related to CNS disorders. Although some studies have analyzed the degradability of silk fibroin in non-cerebral tissues (almost exclusively upon non-inflammatory conditions), the stability of silk hydrogel scaffolds in the inflammatory nervous system has not been studied in depth. In this study, the stability of silk fibroin hydrogels exposed to different neuroinflammatory contexts has been explored using an in vitro microglial cell culture and two in vivo pathological models of cerebral stroke and Alzheimer's disease. This biomaterial was relatively stable and did not show signs of extensive degradation across time after implantation and during two weeks of in vivo analysis. This finding contrasted with the rapid degradation observed under the same in vivo conditions for other natural materials such as collagen. Our results support the suitability of silk fibroin hydrogels for intracerebral applications and highlight the potentiality of this vehicle for the release of molecules and cells for acute and chronic treatments in cerebral pathologies.

Study on a Natural Silk Cocoon Membrane-Based Versatile and Stable Immunosensing Platform via Directional Immunoaffinity Recognition

The development of immunosensing assays for in vitro diagnostics has attracted great attention in recent years. Various substrate materials and immobilization methods of biomolecules were exploited for immunosensors, but their bioactivity and longevity have been facing serious challenges. To address this limitation, we investigated a natural silk cocoon membrane as immunosensing substrate material. By using its intrinsic properties, the target biomolecules were immobilized on the membrane through directional immunoaffinity recognition. The silk cocoon membrane-based immunosensor showed great potential for both qualitative and quantitative immunoassays, through naked-eye observation or analyzing the change in red color intensity, respectively. The immunosensor exhibited significant detection capability for anti-D (titer 1:1024) sensitized red blood cells. The colorimetric responses of concentrations ranged from 1 μg/mL to 1 ng/mL, and the detection limit for anti-D was 3.4 ng/mL. The immunosensor also showed excellent stability for the immobilized antibodies when stored at 4 and 25 °C; the bioactivity remained unchanged or slightly declined within 40 weeks. Even at 37 °C, the bioactivity began to decline after 12 weeks. This current work highlights the potential of using the natural silk cocoon membrane as a substrate for a versatile and thermally stable immunosensing platform for application in immunoassays.

EPR-based study to monitor Free Radicals in Treated Silk Fibroin with Anthocyanins

Bioactive materials of natural origin have great demand in industry and medicine due to their versatility and useful properties. The main purpose of this work is to prepare biocomposites for the dual purpose of modified silk fibroin (Bombyx mori L.), which protects against the destructive effects of bioactive, antioxidant and ultraviolet rays. For this purpose, an aqueous extract of autumn leaves of the anthocyanin-rich smoke tree plant (Cotinus coggygria L.) was applied. 2% thiourea solution was used to increase the durability of the modified SF to external influences and for use in textiles. The intensity of free radicals in silk fibroin-anthocyanin (SFA) and silk fibroin-anthocyanin-thiourea (SFAT) biocomposites modified by the Electron Paramagnetic Resonance (EPR) method was studied. Maximum adsorption time was determined 20 minutes and the intensity of free radicals in SFA bio-composite was 80-85% and in SFAT biocomposite 50-55% in relation to silk fibroin untreated. For biomedical use of SFA, the radical scavenger activity kinetics were studied on a UV-2700 spectrophotometer and radical capture activity was calculated: RSA% (bioextract) = 73.52 ± 0.5, RSA% (SF) = 6.42 ± 0.4, RSA% (SFA) = 45.23 ± 0.8