Evaluation of silymarin/duck's feet-derived collagen/hydroxyapatite sponges for bone tissue regeneration.

Tissue engineered scaffolds, made of natural derived materials, have the potential to be used in bone regeneration fields due to the biocompatible and biodegradable features. In this study, we propose duck's feet-derived collagen (DC) sponges blended with hydroxyapatite (HAp), incorporated with different concentrations of silymarin (Smn), for improved bone regeneration. The morphological and structural properties of DC/HAp and DC/HAp loaded with 25, 50 and 100 µM of Smn sponges were analyzed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). In vitro evaluations were carried out on rabbit bone marrow stem cells (rBMSCs) using MTT assay for cell proliferation, ALP assay for osteogenic differentiation and reverse transcription-polymerase chain reaction (RT-PCR) for expression of mRNAs. For the evaluation of new bone formation in vivo, histological analysis and micro computed tomography (µCT) were used. Preliminary results, on Smn/DC/HAp morphology and mechanical properties, showed an interconnected porosity suitable for cells ingrowth and a higher compressive strength with the presence of Smn. Similarly, the cells proliferation and ALP activity modulation were positively influenced by the Smn content. Especially, the 100 µM Smn/DC/HAp sponge efficiently enhances the rBMSCs adhesion, growth and gene expression of osteogenic markers. The enhanced osteoinductive effects of sponges blended with Smn were confirmed using µ-CT and histological evaluations. In conclusion, results suggest that collagen sponges represent an excellent environment for cells growth and proliferation, while Smn plays an important role to improve materials osteogenic properties.

Characterization of surface modified glycerol/silk fibroin film for application to corneal endothelial cell regeneration.

Corneal endothelial cells (CEnCs) play a fundamental role in maintaining the transparency of the cornea. CEnCs lose their full proliferating capacity when tissue damages occur. The loss in proliferation rate is associated with corneal edema and decrease in visual acuity, leading in severe cases, to blindness. In these situations, a corneal transplant is usually needed to restore the original tissue functions. Tissue engineering is an efficient alternative for the production of implantable films, which can regenerate the tissue functions regulating at the same time the immune-response. In this study, we proposed a stable and transparent film, composed of silk fibroin modified with glycerol (G/SF), as a potential substrate for corneal endothelial cells regeneration. Our results confirmed that G/SF films have a uniform structure, rougher surface and lower thickness respect to the SF film. In vitro tests show that G/SF films can induce a slight increase in CEnCs initial adhesion and proliferation rate if compared with the SF film. Morphology and gene expression evaluations demonstrated that the bioactive effects of silk fibroin were not affected by the presence of glycerol. For this reason, the G/SF films are suitable as CEnCs carrier and promising for the corneal damages treatments.

Nature-derived epigallocatechin gallate/duck's feet collagen/hydroxyapatite composite sponges for enhanced bone tissue regeneration.

Scaffolds mimicking structural and chemical characteristics of the native bone tissues are critical for bone tissue engineering. Herein, we have developed and characterized epigallocatechin gallate/duck's feet collagen/hydroxyapatite (EGCG/DC/HAp) composite sponges that enhanced the bone tissue regeneration. The three-dimensional composite sponges were synthesized by loading various amounts (i.e. 1, 5 and 10 µM) of EGCG to duck feet derived collagen followed by freeze-drying and then coating with hydroxyapatite. Several measuremental techniques were employed to examine the properties of the as-fabricated composite sponges including morphology and structure, porosity, compressive strength, etc. and as well compared with pristine duck feet derived collagen. SEM observations of EGCG/DC/HAp sponges showed the formation of a highly porous collagen matrix with EGCG embodiment. The porosity and pore size of sponges were found to increase by high EGCG content. The compressive strength was calculated as 3.54 ± 0.04, 3.63 ± 0.03, 3.89 ± 0.05, 4.047 ± 0.05 MPa for 1, 5 and 10 µM EGCG/DC/HAp sponges, respectively. Osteoblast-like cell (BMSCs isolated from rabbit) culture and in vivo experiments with EGCG/DC/HAp sponges implanted in nude mouse followed by histological staining showed enhanced cell internalization and attachment, cell proliferation, alkaline phosphatase expressions, indicating that EGCG/DC/HAp sponges have ahigh biocompatibility. Moreover, highEGCG content in the EGCG/DC/HAp sponges have led to increased cellular behavior. Collectively, the 5 µM of EGCG/DC/HAp sponges were suggested as the potential candidates for bone tissue regeneration.

Osteogenesis evaluation of duck's feet-derived collagen/hydroxyapatite sponges immersed in dexamethasone.

BACKGROUND: The aim of this study was to investigate the osteogenesis effects of DC and DC/HAp sponge immersed in without and with dexamethasone. METHODS: The experimental groups in this study were DC and DC/HAp sponge immersed in without dexamethasone (Dex(-)DC and Dex(-)-DC/HAp group) and with dexamethasone (Dex(+)-DC and Dex(+)-DC/HAp group). We characterized DC and DC/HAp sponge using compressive strength, scanning electron microscopy (SEM). Also, osteogenic differentiation of BMSCs on sponge (Dex(-)DC, Dex(-)-DC/HAp, Dex(+)-DC and Dex(+)-DC/HAp group) was assessed by SEM, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide (MTT) assay, alkaline phosphatase (ALP) activity assay and reverse transcription-PCR (RT-PCR). RESULTS: In this study, we assessed osteogenic differentiation of BMSCs on Duck's feet-derived collagen (DC)/HAp sponge immersed with dexamethasone Dex(+)-DC/HAp. These results showed that Dex(+)-DC/HAp group increased cell proliferation and osteogenic differentiation of BMSCs during 28 days. CONCLUSION: From these results, Dex(+)-DC/HAp can be envisioned as a potential biomaterial for bone regeneration applications.