Influence of the Casting Concentration on the Mechanical and Optical Properties of FA/CaCl2-Derived Silk Fibroin Membranes

Abstract

In this study, we describe the manufacturing and characterization of silk fibroin membranes derived from the silkworm Bombyx mori. To date, the dissolution process used in this study has only been researched to a limited extent, although it entails various potential advantages, such as reduced expenses and the absence of toxic chemicals in comparison to other conventional techniques. Therefore, the aim of this study was to determine the influence of different fibroin concentrations on the process output and resulting membrane properties. Casted membranes were thus characterized with regard to their mechanical, structural and optical assets via tensile testing, SEM, light microscopy and spectrophotometry. Cytotoxicity was evaluated using BrdU, XTT, and LDH assays, followed by live–dead staining. The formic acid (FA) dissolution method was proven to be suitable for the manufacturing of transparent and mechanically stable membranes. The fibroin concentration affects both thickness and transparency of the membranes. The membranes did not exhibit any signs of cytotoxicity. When compared to other current scientific and technical benchmarks, the manufactured membranes displayed promising potential for various biomedical applications. Further research is nevertheless necessary to improve reproducible manufacturing, including a more uniform thickness, less impurity and physiological pH within the membranes.

Doping of casted silk fibroin membranes with extracellular vesicles for regenerative therapy: a proof of concept

“…No cytotoxic effects could be observed, neither in the functionalized membranes with EVs nor in the control group. Similar results could already be presented in previous studies from our research group 33 , 51 . The enhanced viability observed for L929 cells in both SF with EVs and SF without EVs compared to the toxic control group suggests a potential protective effect against the tested toxic agent.…”

Biodegradable Silk Fibroin Matrices for Wound Closure in a Human 3D Ex Vivo Approach

“…We quantitatively analyzed their beneficial impact on keratinocyte activity and the overall dynamics of wound healing. Our previous studies have already revealed that additive-free electrospun nonwovens [ 28 ] and formic acid/CaCl 2 -derived silk fibroin membranes [ 29 ] exhibit high biocompatibility and regenerative properties supporting fibroblast adhesion and proliferation. In here, biocompatibility was affirmed through both direct and indirect assays, indicating viability levels that closely mirrored or surpassed control conditions, with the membranes and nonwovens showing low cytotoxic levels well below the 30% threshold.…”

“…Silk fibroin aqueous solution was obtained using PureSilk ® technology (Fibrothelium GmbH, Aachen, Germany), enabling medical grade quality production of silk on an industrial scale for a broad range of concentrations. Briefly, fibroin was separated from sericin by degumming it in hot alkali solution before dissolving it in a proprietary non-toxic solvent system based on Ajisawa’s reagent [ 28 , 29 , 30 ].…”

“…The production of silk fibroin membranes involved silk fibroin casting according to our previous study [ 29 , 30 ]: The fibroin solution was cast into a polytetrafluoroethylene (PTFE) mold and left to dry for 24 h at 21 °C under a laminar flow hood, resulting in a delicate membrane with a thickness of approximately 0.1–0.15 mm. To fit them into the target wounds, disks of 3 mm diameter were created using a biopsy punch.…”