In Situ Mineralizing Spinning of Strong and Tough Silk Fibers for Optical Waveguides

Abstract

Biopolymer-based optical waveguides with low-loss light guiding performance and good biocompatibility are highly desired for applications in biomedical photonic devices. Herein, we report the preparation of silk optical fiber waveguides through bioinspired in situ mineralizing spinning, which possess excellent mechanical properties and low light loss. Natural silk fibroin was used as the main precursor for the wet spinning of the regenerated silk fibroin (RSF) fibers. Calcium carbonate nanocrystals (CaCO3 NCs) were in situ grown in the RSF network and served as nucleation templates for mineralization during the spinning, leading to the formation of strong and tough fibers. CaCO3 NCs can guide the structure transformation of silk fibroin from random coils to β-sheets, contributing to enhanced mechanical properties. The tensile strength and toughness of the obtained fibers are up to 0.83 ± 0.15 GPa and 181.98 ± 52.42 MJ·m–3, obviously higher than those of natural silkworm silks and even comparable to spider silks. We further investigated the performance of the fibers as optical waveguides and observed a low light loss of 0.46 dB·cm–1, which is much lower than natural silk fibers. We believed that these silk-based fibers with excellent mechanical and light propagation properties are promising for applications in biomedical light imaging and therapy.

Ultra‐Strong and Transparent Biomimetic Nanocomposite through Orientation Effects and In Situ Biomineralization

“…These results demonstrate the enhanced alignment of cellulose crystallites in PCB-30, as compared to BC-30, indicating that the CPO contributes to cellulose crystalline orientation. [34] The effective integration of organic-inorganic phases and the hierarchically ordered structure is advantageous to improve the mechanical properties of the nanocomposite films. To investigate the mechanical properties of the nanocomposite films, pure BC film, binary composite films (PB and CB), and ternary PCB film were prepared, and their mechanical performances were compared.…”

Bioinspired Strong and Tough Organic–Inorganic Hybrid Fibers

“…3) β-sheet rich silk nanofiber (BSNF) hydrogel [30] 2 6 80 1 4) Regenerated silk fiber with calcium carbonate nanocrystals [31] 830 19 28 182…”

Silk Protein-Mediated Biomineralization: From Bioinspired Strategies and Advanced Functions to Biomedical Applications

“…In addition, Zhang et al used the in situ mineralization method to composite the nanocrystalline calcium carbonate with SF prepared by wet spinning, producing a mechanically superior optical fiber that has excellent optical propagation properties. 88 The incorporation of CaCl 2 and Na 2 HPO 4 into SS aqueous solutions can induce the formation of HA nanoneedles. These HA nanoneedlebased SBBMs significantly improve the viability of bone marrow mesenchymal stem cells (BMSCs) and osteogenic differentiation.…”

“…Similarly, CuS, AgCl, , and Ag 3 PO 4 have been successfully combined with silk proteins through biomineralization, resulting in SBBMs with excellent antibacterial activity. In addition, Zhang et al used the in situ mineralization method to composite the nanocrystalline calcium carbonate with SF prepared by wet spinning, producing a mechanically superior optical fiber that has excellent optical propagation properties . The incorporation of CaCl 2 and Na 2 HPO 4 into SS aqueous solutions can induce the formation of HA nanoneedles.…”