Biocompatible and Printable Ionotronic Sensing Materials Based on Silk Fibroin and Soluble Plant-Derived Polyphenols

Abstract

The emergence of ionotronic materials has been recently exploited for interfacing electronics and biological tissues, improving sensing with the surrounding environment. In this paper, we investigated the synergistic effect of regenerated silk fibroin (RS) with a plant-derived polyphenol (i.e., chestnut tannin) on ionic conductivity and how water molecules play critical roles in regulating ion mobility in these materials. In particular, we observed that adding tannin to RS increases the ionic conductivity, and this phenomenon is accentuated by increasing the hydration. We also demonstrated how silk-based hybrids could be used as building materials for scaffolds where human fibroblast and neural progenitor cells can highly proliferate. Finally, after proving their biocompatibility, RS hybrids demonstrate excellent three-dimensional (3D) printability via extrusion-based 3D printing to fabricate a soft sensor that can detect charged objects by sensing the electric fields that originate from them. These findings pave the way for a viable option for cell culture and novel sensors, with the potential base for tissue engineering and health monitoring.

Silk Fibroin Hybrids for Biological Scaffolds with Adhesive Surface and Adaptability to the Target Tissue Change

“…Fibroblast and NPC morphology, confluence, and growth indicate the excellent biocompatibility of RS hybrids (Figures 5A and B). In addition, we observed that low doses of tannin were not cytotoxic to fibroblasts and NPCs, confirming their antioxidant and cytoprotective properties (32).…”

“…The cells of the HepG2 line were cultured in EMEM (Eagle's minimal essential medium), with the addition of 10% heat inactivated fetal bovine serum (FBS), 1% non-essential amino acids, 1 mM sodium pyruvate, 2 mM of L-glutamine and antibiotics (100 U/mL penicillin, 100 μg/mL streptomycin). After a treatment of 24 h and one of 48 h, to evaluate the biocompatibility of these compounds, the MTT test was used (32), a test that measures cellular metabolic activity based on the reduction of a yellow tetrazolium salt (3-(4, 5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide or MTT) to purple formazan crystals by metabolically active cells. For this evaluation, the HepG2 cells were seeded in a 96-well plate at a cell density of 1 × 104 cells/well; after 24 hours, eight different dilutions of stock solutions (1 mg/mL) replaced the complete fresh medium and MTT reagent (0.5 μg/μL) was added to each well for 3 hours at 37° C.…”

Biomaterial Inks from Peptide-Functionalized Silk Fibers for 3D Printing of Futuristic Wound-Healing and Sensing Materials

“…As shown in Figure 7 a, the resistivity decreases as a function of relative humidity. This effect is a combination of the hygroscopic behavior of the peptide-functionalized silk and the activation of Ca 2+ ion mobility due to water absorption [ 25 ]. To investigate humidity’s effect on the electrical resistance of the MO-07/RS grid, we evaluated the change in current–voltage characteristics at different values of relative humidity (see Figure S3 ).…”

Advances in Preparation and Properties of Regenerated Silk Fibroin

“…Processing forms Filament, film, gel, nanofiber Film Film, nanofiber, electrostatic spinning fiber mat, SF coating Applications Tissue engineering [148], wound healing [146], drug delivery [147], tissue adhesion [156], electrochemistry [157], spinning [144] -Tissue engineering [158], drug release [159], spinning [145] 1 SF solution is difficult to gelate (D); 2 SF solution has good film-forming properties (G).…”