Comparative Study of Ultrasonication-Induced and Naturally Self-Assembled Silk Fibroin-Wool Keratin Hydrogel Biomaterials |
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Authors: | Trang Vu Ye Xue Trinh Vuong Matthew Erbe Christopher Bennet Ben Palazzo Lucas Popielski Nelson Rodriguez Xiao Hu |
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Affiliation: | 1Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028, USA; (T.V.); (T.V.); (M.E.); (C.B.); (B.P.); (L.P.); (N.R.);2Department of Biomedical Engineering, Rowan University, Glassboro, NJ 08028, USA; ;3Department of Chemical Engineering, Rowan University, Glassboro, NJ 08028, USA;4Department of Biomedical and Translational Sciences, Rowan University, Glassboro, NJ 08028, USA |
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Abstract: | This study reports the formation of biocompatible hydrogels using protein polymers from natural silk cocoon fibroins and sheep wool keratins. Silk fibroin protein contains β-sheet secondary structures, allowing for the formation of physical cross-linkers in the hydrogels. Comparative studies were performed on two groups of samples. In the first group, ultrasonication was used to induce a quick gelation of a protein aqueous solution, enhancing the ability of Bombyx mori silk fibroin chains to quickly entrap the wool keratin protein molecules homogenously. In the second group, silk/keratin mixtures were left at room temperature for days, resulting in naturally-assembled gelled solutions. It was found that silk/wool blended solutions can form hydrogels at different mixing ratios, with perfectly interconnected gel structure when the wool content was less than 30 weight percent (wt %) for the first group (ultrasonication), and 10 wt % for the second group (natural gel). Differential scanning calorimetry (DSC) and temperature modulated DSC (TMDSC) were used to confirm that the fibroin/keratin hydrogel system was well-blended without phase separation. Fourier transform infrared spectroscopy (FTIR) was used to investigate the secondary structures of blended protein gels. It was found that intermolecular β-sheet contents significantly increase as the system contains more silk for both groups of samples, resulting in stable crystalline cross-linkers in the blended hydrogel structures. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the samples’ characteristic morphology on both micro- and nanoscales, which showed that ultrasonic waves can significantly enhance the cross-linker formation and avoid phase separation between silk and keratin molecules in the blended systems. With the ability to form cross-linkages non-chemically, these silk/wool hydrogels may be economically useful for various biomedical applications, thanks to the good biocompatibility of protein molecules and the various characteristics of hydrogel systems. |
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Keywords: | silk fibroin wool keratin hydrogel DSC FTIR SEM AFM |
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