Enhanced Silk Fibroin/Sericin Composite Film: Preparation, Mechanical Properties and Mineralization Activity

Abstract

The periosteum plays an important role in bone formation and reconstruction. One of the reasons for the high failure rate of bone transplantation is the absence of the periosteum. Silk fibroin (SF) and silk sericin (SS) have excellent biocompatibility and physicochemical properties, which have amazing application prospects in bone tissue engineering, but lacked mechanical properties. We developed a series of SF/SS composite films with improved mechanical properties using boiling water degumming, which caused little damage to SF molecular chains to retain larger molecules. The Fourier transform infrared spectroscopy and X-ray diffraction results showed that there were more β-sheets in SF/SS films than in Na2CO3 degummed SF film, resulting in significantly improved breaking strength and toughness of the composite films, which were increased by approximately 1.3 and 1.7 times, respectively. The mineralization results showed that the hydroxyapatite (HAp) deposition rate on SF/SS composite films was faster than that on SF film. The SF/SS composite films effectively regulated the nucleation, growth and aggregation of HAp-like minerals, and the presence of SS accelerated the early mineralization of SF-based materials. These composite films may be promising biomaterials in the repair and regeneration of periosteum.

Effect of degumming degree on the structure and tensile properties of RSF/RSS composite films prepared by one-step extraction

“…Therefore, compared with RSF C film prepared by Na 2 CO 3 degumming, the breaking strength of RSF films was increased significantly. This result is consistent with those obtained by using sodium dodecyl sulfate–polyacrylamide gel electrophoresis in our previous study; thus, boiling water degumming causes less damage to macromolecules of fibroin fibres, resulting in higher molecular weight compared with Na 2 CO 3 degumming 24 . In the presence of sericin, the breaking elongation of RSF/RSS composite films was significantly improved, and dependent on the sericin content (Fig.…”

“…Therefore, RSF film and RSF/RSS 2 composite film were considered alternative hard-tissue repair materials such as dura or periosteum. However, when the degumming rate was lower, the higher content of sericin resulted in an increase in solution viscosity and disruption to the ordered arrangement of silk fibroin macromolecular chains 24 , leading to reduced breaking strength of RSF/RSS 1 film to even less than that of RSF C film prepared by Na 2 CO 3 degumming.…”

“…Thirty-two scans were recorded with a resolution of 4 cm −1 and a scanning range of 500–4000 cm −1 . In addition, we semi-quantitatively analysed the molecular conformation by deconvolution of the amide I band using Peakfit v4.12 software as reported previously 24 .…”

“…We developed a boiling water degumming method to obtain RSF/RSS composite solutions by controlling the degumming rates in order to retain high-molecular-weight silk protein 24 . This method was not necessary to prepare RSF and RSS separately and then blend them, hence we considered it a one-step extraction method.…”

Advances in Multifunctional Bioactive Coatings for Metallic Bone Implants

“…The most commonly used synthetic polymers for periosteum development are polylactic L-lactic-co-glycolic acid (PLGA), polyurethanes (PU), polyethylene glycol, (PEG), polycaprolactone (PCL) and poly L-lactic acid (PLLA), and polymethylmethacrylate (PMMA) [308]. Synthetic polymers are usually hydrophobic and possess no antibacterial activity.…”