Facile One-Pot Method for All Aqueous Green Formation of Biocompatible Silk Fibroin-Poly(Ethylene Oxide) Fibers for Use in Tissue Engineering

Abstract

Silk fibroin (SF) fibers are highly regarded in tissue engineering because of their outstanding biocompatibility and tunable properties. A challenge remains in overcoming the trade-off between functioning and biocompatible fibers and the use of cytotoxic, environmentally harmful organic solvents in their processing and formation. The aim of this research was to produce biocompatible SF fibers without the use of cytotoxic solvents, via pressurized gyration (PG). Aqueous SF was blended with poly(ethylene oxide) (PEO) in ratios of 80:20 (labeled SF-PEO 80:20) and 90:10 (labeled SF-PEO 90:10) and spun into fibers using PG, assisted by a range of applied pressures and heat. Pure PEO (labeled PEO-Aq) and SF solubilized in hexafluoro-isopropanol (HFIP) (labeled SF-HFIP) and aqueous SF (labeled SF-Aq) were also prepared for comparison. The resulting fibers were characterized using SEM, TGA, and FTIR. Their in vitro cell behavior was analyzed using a Live/Dead assay and cell proliferation studies with the SaOS-2 human bone osteosarcoma cell line (ATCC, HTB-85) and human fetal osteoblast cells (hFob) (ATCC, CRL-11372) in 2D culture conditions. Fibers in the micrometer range were successfully produced using SF-PEO blends, SF-HFIP, and PEO-Aq. The fiber thickness ranged from 0.71 ± 0.17 μm for fibers produced using SF-PEO 90:10 with no applied pressure to 2.10 ± 0.78 μm for fibers produced using SF-PEO 80:10 with 0.3 MPa applied pressure. FTIR confirmed the presence of SF via amide I and amide II bands in the blend fibers because of a change in structural conformation. No difference was observed in thermogravimetric properties among varying pressures and no significant difference in fiber diameters for pressures. SaOS-2 cells and hFOb cell studies demonstrated higher cell densities and greater live cells on SF-PEO blends when compared to SF-HFIP. This research demonstrates a scalable and green method of producing SF-based constructs for use in bone-tissue engineering applications.

Pressurized Gyration: Fundamentals, Advancements, and Future

“…), [27,35,38,[53][54][55][56] biopolymer fibers were also spun using PG, including silk fibroin, polyhydroxyalkanoates, starch, etc. [57][58][59][60] These fibers have broad prospects in biomedical applications due to their inherent biocompatibility and environmental friendliness. Carbon nanofibers with polyacrylonitrile as the precursor can be easily produced by PG.…”

“…achieved the efficient production of aqueous‐based silk fibroin using PG. [ 58 ] Osteocytes exhibited significant cellular activity and proliferation on these aligned silk fibroin fibers. The core‐sheath fibers manufactured by core‐sheath PG provide a fascinating new strategy for tissue engineering.…”

Instantaneous Formation of Silk Protein Aerosols and Fibers with a Portable Spray Device under Ambient Conditions

“…To address these limitations, recently, a scalable and green method based on the pressurized gyration spinning process was employed to produce silk fibers that could be utilized in bone-tissue engineering applications. [55] In this work, we report the fabrication of silk fibroin proteinbased materials ranging from fibers to aerosols in situ through control of the instantaneous conformational transition of silk fibroin aqueous solutions from random coils to β-sheet crystalline structures by mixing the silk solution with PEG solution using a portable spray device. PEG was chosen as a β-sheet accelerating agent, where the molecular weight of PEG was 10 kDa (hereafter referred to as PEG10k), because it is water soluble, nontoxic, and a bioinert synthetic polymer that is widely used in pharmaceutical industries as a drug excipient.…”

“…To address these limitations, recently, a scalable and green method based on the pressurized gyration spinning process was employed to produce silk fibers that could be utilized in bone‐tissue engineering applications. [ 55 ]…”

Synthesis of hollow fibroin using calcium carbonate as a template

“…7,11 It is recognized as an essential class of biomaterial and used in various biomedical applications, such as tissue engineering, 12,13 disease models, 14 implant devices, 15 and drug delivery. 16 Moreover, it offers a variety of material types, such as porous sponges, 17 fibers, 18,19 hydrogels, 20 non-woven mats, 21 tubes, 22 and films. 23 Hollow micro/nanostructures have received significant attention due to their tunable physical and chemical properties.…”