Silk-sericin degummed wastewater solution-derived and nitrogen enriched porous carbon nanosheets for robust biological imaging of stem cells.

Appreciated raw materials like silk-sericin can be recovered from silk-textile industrial waste for the production of novel functional nanomaterials. In this study, highly fluorescent sericin based carbon nanosheets (SCN) were produced from industrial wastewater containing silk-sericin as a precursor, and was applied as bio-imaging application for oral fat stem cells. A simple one-pot, hydrothermal carbonization method was used to produce SCN at a 180°C. The obtained hydrothermal carbons exhibited strong fluorescence properties due to the presence of strong polar groups, such as carboxyl, amino and amide groups in the surface. Heteroatom functionalization of the SCN leads to the property of fluorescence due to enriched nitrogen and was confirmed by X-ray photoelectron and Fourier transform infrared spectroscopy. The plate-like morphology of SCN about 35nm in size was evaluated by transmission electron microscopy. The carbon 13 nuclear magnetic resonance results revealed that nano-sized fluorescent SCN formed during carbonization and functionalization occurred through dehydration of the sericin protein. Moreover, the prepared SCNs demonstrated low toxicity and their suitability for bio-imaging applications was demonstrated to the oral fat stem cells. Overall, sericin degumming wastewater from the silk textile industry can be utilized for the production of SCNs for stem cells bio-imaging applications.

Evaluation of nanoarchitectured collagen type II molecules on cartilage engineering.

Scaffold architecture, including the geometry and dimension of scaffolds, is an important parameter in cell adhesion, migration, proliferation, and differentiation. Following the characterization of collagen type II nanoarchitectured molecules, collagen fibrils (CNFs) and collagen spheres (CNPs) prepared using a high-voltage electric field in our laboratory, we proposed to use these nanoarchitectured molecules to assess their influence on the culturing of chondrocytes in stirred bioreactors. The results demonstrate that chondrocytes rapidly formed more and larger chondrocyte pellets (spheroids) after the addition of nanoarchitectured molecules into the culture medium. The maintenance of chondrocytes with round morphology and increased glycosaminoglycan secretion indicated that these spheroids contained viable and un-dedifferentiated chondrocytes. No significant increases in DNA content were detected. These results show that the introduction of these molecules did not affect chondrocyte proliferation during a 3-day culture period. After the addition of CNPs and CNFs into the culture medium, the expression levels of collagen type II and aggrecan genes in chondrocytes increased significantly as demonstrated by real-time PCR analysis. Interestingly, chondrocytes exhibited distinct collagen type II and aggrecan gene expression profiles in culture with CNPs and CNFs. The aggrecan gene expression level of the chondrocytes was 2.5-fold greater following CFN addition than following the addition of CNPs. In contrast, the collagen type II expression level of the chondrocytes was 2.2-fold greater following the addition of CNPs than following the addition of CNFs. The chondrocyte pellets rapidly restored defects in articular cartilage during a 1-month implantation period in a rabbit model.