The bone-mimicking effect of calcium phosphate on composite chitosan scaffolds in maxillofacial bone tissue engineering.

This research explored a new trend in biomaterials science. The bone-mimicking effect of calcium phosphate on chitosan composite scaffolds was evaluated. Chitosan with 2% calcium phosphate was found to have suitable bone-mimicking performance for maxillofacial bone tissue engineering.

Mimicked scaffolds based on coated silk woven fabric with gelatin and chitosan for soft tissue defect in oral maxillofacial area.

Soft tissue defects in the oral maxillofacial area are critical problems for many patients and, in some cases, patients require an operation coupled with a performance scaffold substitution. In this research, mimicked anatomical scaffolds were constructed using gelatin- and chitosan-coated woven silk fibroin fabric. The morphologies, crystals, and structures were observed and then characterized using scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry, respectively. Physical performance was evaluated from the swelling behavior, mechanical properties, and biodegradation, while the biological performance was tested with fibroblasts and keratinocytes, after which cell proliferation, viability, and histology were evaluated. The results revealed that a coated woven silk fibroin fabric displayed a crystal structure of silk fibroin with amorphous gelatin and chitosan layers. Also, the coated fabrics contained residual water within their structure. The physical performance of the coated woven silk fibroin fabric with gelatin showed suitable swelling behavior and mechanical properties along with acceptable biodegradation for insertion at a defect site. The biological performances including cell proliferation, viability, and histology were suitable for soft tissue reconstruction at the defect sites. Finally, the results demonstrated that mimicked anatomical scaffolds based on a gelatin layer on woven silk fibroin fabric had the functionality that was promising for soft tissue construction in oral maxillofacial defect.

In vivo evaluation of modified silk fibroin scaffolds with a mimicked microenvironment of fibronectin/decellularized pulp tissue for maxillofacial surgery.

This study aimed to carry out in vivo testing of the formation of new bone by modified silk fibroin scaffolds with a mimicked microenvironment of fibronectin/decellularized pulp in bone defects. Silk fibroin scaffolds were fabricated into three-dimensional scaffolds before being coated with fibronectin/decellularized pulp. The coated scaffolds were implanted into rabbits. Twenty-four bicortical calvarial defects in 12 rabbits were divided randomly into two groups: non-coated and coated silk fibroin scaffolds. The rabbits were sacrificed 2, 4 and 8 weeks after operation for evaluation of new bone formation. The morphology of the scaffolds, new bone formation and histology were evaluated by scanning electron microscopy, micro-CT and hematoxylin and eosin staining, respectively. The results showed that the coated silk fibroin scaffolds had a fibrillar network and crystal particles in the porous structure. The coated silk fibroin scaffolds demonstrated the ability to induce the formation of new bone with low inflammation and high vascularization. The results indicated that the modified silk fibroin scaffolds showed suitable biological performance and promise for bone regeneration in maxillofacial surgery.

Fabrication, characterization and cell cultures on a novel chitosan scaffold.

Chitosan has been used as scaffolds with various methods of fabrication including expensive commercial available ones for tissue engineering. The objective of this study is to assemble our novel method of chitosan scaffold fabrication in economical and uncomplicated way that suitable for dental pulp stem cell (DPSC) and stem cells of human exfoliated deciduous teeth (SHED). Chitosan scaffolds (2% and 3%) were fabricated in an uncomplicated procedure, including centrifugation and freeze-drying steps. The chitosan scaffolds were compared and the pore size, swelling and degradation were assessed. In addition, the cytocompatibility was assessed of chitosan scaffolds seeded with DPSC and SHED. The pore size of 2% and 3% chitosan scaffolds were similar being 188.71 ± 51.90 µm and 195.30 ± 67.21 µm, respectively. Swelling ratios of 3% chitosan scaffolds were significantly lower than those of 2% chitosan scaffolds. Dimension of scaffolds changed in first 5 minutes. After that, those scaffolds could maintain their dimension. Chitosan scaffolds degraded as from day 7. No differences were found between 2% and 3% chitosan scaffolds. The scaffolds were shown to be non-toxic and to promote DPSCs and SHED growth. The viability of DPSCs and SHED on 2% scaffolds proved to be higher than that of the 3% scaffold group. This study suggested that chitosan scaffolds fabricated with our novel method were suitable for the growth and survival of DPSC and SHED.

Comparative study of different centrifugation protocols for a density gradient separation media in isolation of osteoprogenitors from bone marrow aspirate.

INTRODUCTION: Human bone marrow contains osteoprogenitors capable of differentiating into osteoblasts. Density gradient centrifugation (DGC) is a commonly used method to isolate osteoprogenitors from bone marrow. Numerous studies used different dilution and centrifugation protocols, which might affect cell yields and quality. Moreover, the relative isolation efficiencies of the different separation protocols have not been investigated. This study compares the enrichment efficacy of the two different centrifugation protocols for a commonly used DGC media in isolation of osteoprogenitors. MATERIAL AND METHOD: Bone marrow was aspirated from human anterior iliac crests. Osteoprogenitors are isolated with Ficoll DGC media. A centrifugal force of 400 g and 1:1 dilution was compared with the centrifugal force of 1000 g after three dilution times with a buffer. RESULTS: The average numbers of isolated cells were significantly higher when using lower centrifugal force with 1:1 dilution, however, there was no detectable difference between Colony-forming unit-fibroblast (CFU-F) forming capacity, STRO-1 positivity, osteogenic differentiation or mineralization abilities between protocols. CONCLUSION: Both protocols could isolate competent and functional osteoprogenitors, while a lower centrifugal force (400 g) with 1:1 dilution produced recovery of more osteoprogenitors.