Abstract:Silk fibroin-derived polypeptides (FDPs) are polypeptides resulting from the enzymatic separation of the hydrophobic crystalline (C
p
) and hydrophilic electronegative amorphous (C
s
) components of silk fibroin (SF). The role of these polypeptides in promoting the nucleation of hydroxyapatite (HA) has been previously investigated, yet is still not fully understood. Here we study the potential of HA mineralization via FDPs incorporated at 1:10, 1:2 and 1:1 in a pla… Show more
“…20,21 Notably, the position of 1623 cm −1 confirmed conformational change of water-insoluble β form of SF. 22 Figure 2.Characterization of SF and β-TCP nanoparticles ((a): TEM image of β-TCP nanoparticles; (b): XRD pattern of β-TCP nanoparticles; and (c): AIR-FTIR pattern of SF solution).…”
To investigate the osteogenesis of β-tricalcium phosphate nanoparticles-incorporated silk fibroin (SF/β-TCP) composite scaffolds, SF-based scaffolds with different β-TCP proportion (2/1, 1/1, and 1/2) were fabricated by freeze-drying technology in the present study. Structural and physicochemical properties of SF-based scaffolds were evaluated by using scanning electron microscope, X-ray diffraction, Fourier transformed infrared spectroscopy (ATR-FTIR) and transmission electron microscope. Biocompatibility and osteogenesis of SF/β-TCP scaffolds were investigated by using bone marrow mesenchymal stem cells (BMSCs). Eight New Zealand rabbits were selected, while four 8-mm-diameter calvarial defects were created in each rabbit to place SF/β-TCP scaffolds. The harvested specimens at 4 and 12 weeks were used to evaluate the bone forming ability by micro-CT and histological examination. The results suggested incorporation of β-TCP displayed flake-like pore morphology with proper pore sizes. With the increasing proportion of β-TCP, composite scaffolds exhibited higher compressive strength, lower swelling ratio and degradation rate, as well as enhanced biomineralization capacity. Alkaline phosphatase activity and collagen type I expression levels of BMSCs were significantly increased in the presence of β-TCP nanoparticles. All composite scaffolds with different β-TCP proportion had good bone formation ability at 12 weeks. Among them, SF/β-TCP (1/2) scaffold exhibited the favorable osteogenesis capability which had great potential for applications in bone regeneration.
“…20,21 Notably, the position of 1623 cm −1 confirmed conformational change of water-insoluble β form of SF. 22 Figure 2.Characterization of SF and β-TCP nanoparticles ((a): TEM image of β-TCP nanoparticles; (b): XRD pattern of β-TCP nanoparticles; and (c): AIR-FTIR pattern of SF solution).…”
To investigate the osteogenesis of β-tricalcium phosphate nanoparticles-incorporated silk fibroin (SF/β-TCP) composite scaffolds, SF-based scaffolds with different β-TCP proportion (2/1, 1/1, and 1/2) were fabricated by freeze-drying technology in the present study. Structural and physicochemical properties of SF-based scaffolds were evaluated by using scanning electron microscope, X-ray diffraction, Fourier transformed infrared spectroscopy (ATR-FTIR) and transmission electron microscope. Biocompatibility and osteogenesis of SF/β-TCP scaffolds were investigated by using bone marrow mesenchymal stem cells (BMSCs). Eight New Zealand rabbits were selected, while four 8-mm-diameter calvarial defects were created in each rabbit to place SF/β-TCP scaffolds. The harvested specimens at 4 and 12 weeks were used to evaluate the bone forming ability by micro-CT and histological examination. The results suggested incorporation of β-TCP displayed flake-like pore morphology with proper pore sizes. With the increasing proportion of β-TCP, composite scaffolds exhibited higher compressive strength, lower swelling ratio and degradation rate, as well as enhanced biomineralization capacity. Alkaline phosphatase activity and collagen type I expression levels of BMSCs were significantly increased in the presence of β-TCP nanoparticles. All composite scaffolds with different β-TCP proportion had good bone formation ability at 12 weeks. Among them, SF/β-TCP (1/2) scaffold exhibited the favorable osteogenesis capability which had great potential for applications in bone regeneration.
“…23 Yu et al found Silk fibroin-derived polypeptides promoted osteogenic differentiation for bone tissue engineering. 24 Besides, tricalcium silicate in scaffolds can activate the ERK signal pathway. On these bases, we speculated that the activated ERK signal pathway may be involved in Ad-MSCs proliferation on SF-HA scaffolds.…”
Adipose-derived mesenchymal stem cell (Ad-MSC) with capacities of releasing trophic factors and chondrogenic differentiation was a promising candidate for tracheal reconstruction. Silk fibroin (SF)- hydroxyapatite (HA) scaffolds were fabricated by the freeze-drying method. And Ad-MSCs were co-cultured on the scaffolds for 14 days in vitro. The role of the SF-HA scaffold in regulating the adhesion, growth, and proliferation of Ad-MSCs, and its potential mechanisms were investigated. The identity of Ad-MSCs was confirmed by cell morphology, surface markers, and differentiation characteristics. Cell proliferation, viability, and morphology were observed via CCK-8, live/dead assay, and scanning electron microscopy (SEM). Gene mRNA and protein levels were examined using quantitative real-time polymerase chain reaction and western blotting, respectively. SF-HA scaffolds showed excellent properties of promoting Ad-MSCs adhesion, growth, and proliferation for at least 14 days. In the CCK-8 assay, the relative OD value of Ad-MSCs cultured on SF-HA scaffolds increased ( p < 0.001). Furthermore, live/dead staining showed that the fluorescent coverage increased with time ( p < 0.05). SEM also showed that 3 days after inoculation, the coverage of Ad-MSCs on the SF-HA scaffolds was 78.15%, increased to 92.91% on day 7, and reached a peak of 94.38% on day 14. Extracellular signal-regulated kinase (ERK) mRNA and phosphorylated ERK (pERK) protein expression increased at day 3 ( p < 0.05), followed by a significant decline at day 7 ( p < 0.05). And ERK mRNA expression was positively correlated with Ad-MSCs proliferation ( p < 0.05). In summary, the SF-HA scaffold co-cultured with Ad-MSCs is a promising biomaterial for tracheal repair by activating the ERK signal pathway.
“…The ECM nanofibrillar architecture was stably integrated with the SF/PCL nanofiber scaffold without remarkable delamination, which was speculated to be caused by biophysical entanglements and chemical interactions between collagen fibrils and SF/PCL nanofibers. The electrostatic interaction between the cationic amino groups of collagen and anionic groups of SF likely promoted the stable formation of the NaRE membrane [36]. The Fourier transform infrared spectroscopy analysis confirmed that the NaRE membrane is primarily composed of type I collagen, showing typical peaks of dried collagen including the amide A band (N-H stretching vibration; 3330-3310 cm −1 ), amide I (1640-1660 cm −1 ), amide II (1535-1550 cm −1 ), and amide III (1230-1270 cm −1 ), in addition to the peaks of silk and PCL (figure S1 available online at stacks.iop.org/BF/14/025010/mmedia) [36,37].…”
An extracellular matrix (ECM) membrane made up of ECM hydrogels has great potentials to develop a physiologically relevant organ-on-a-chip because of its biochemical and biophysical similarity to in vivo basement membranes (BMs). However, the limited mechanical stability of the ECM hydrogels makes it difficult to utilize the ECM membrane in long-term and dynamic cell/tissue cultures. This study proposes an ultra-thin but robust and transparent ECM membrane reinforced with silk fibroin (SF)/polycaprolactone (PCL) nanofibers, which is achieved by in situ self-assembly throughout a freestanding SF/PCL nanofiber scaffold. The SF/PCL nanofiber-reinforced ECM (NaRE) membrane shows biophysical characteristics reminiscent of native BMs, including small thickness (< 5 μm), high permeability (< 9 × 10−5 cm s-1), and nanofibrillar architecture (~10 to 100 nm). With the BM-like characteristics, the nanofiber reinforcement ensured that the NaRE membrane stably supported the construction of various types of in vitro barrier models, from epithelial or endothelial barrier models to complex co-culture models, even over two weeks of cell culture periods. Furthermore, the stretchability of the NaRE membrane allowed emulating the native organ-like cyclic stretching motions (10 to 15%) and was demonstrated to manipulate the cell and tissue-level functions of the in vitro barrier model.
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