A biomaterial scaffold acting as a functional substitute for the native extracellular matrix provides space for cell accommodation. In this study, we seeded chondrocytes, isolated from 4- to 6-month-old calves, in 2 types of poly(L-lactide) scaffolds, composed of micro- and nanofibers, and compared the effects on cellular activities. Scanning electron microscopy revealed a well-spread morphology for chondrocytes grown on microfibers. In contrast, chondrocytes on the nanofibers were found to have a rounded morphology and displayed a disorganized actin cytoskeletal structure compared to the organized cytoskeleton seen in well-spread chondrocytes culture on the microfibrous scaffold. Both scaffolds supported chondrocyte proliferation, with a higher rate seen in cultures in nanofibrous scaffold. Quantitative reverse transcription-polymerase chain reaction analysis showed that both cultures supported expression of collagen types I and II and aggrecan. Biochemical analysis showed a higher level of sulfated glycosaminoglycan in the nanofiber culture, confirmed by more intense alcian blue histologic staining. The nanofiber cultures also showed higher immunostaining for collagen types II and IX, aggrecan, and cartilage proteoglycan link protein. Based on these results, we conclude that chondrocytes respond differently to fibrous scaffolds of varying diameters, and that the scaffolds made of nanofibrous biomaterial promote efficient cell-based cartilage tissue engineering.

Degeneration of the intevertebral disc represents a significant musculoskeletal disease burden. Although spinal fusion has some efficacy in pain management, spine biomechanics is ultimately compromised. In addition, there is inherent limitation of hardware-based IVD replacement prostheses, which underscores the importance of biological approaches to disc repair. In this study, we have seeded multipotent, adult human mesenchymal stem cells (MSCs) into a novel biomaterial amalgam to develop a biphasic construct that consisted of electrospun, biodegradable nanofiber scaffold (NFS) enveloping a hyaluronic acid (HA) hydrogel center. The seeded MSCs were induced to undergo chondrogenesis in vitro in the presence of transforming growth factor-β for up to 28 days. The cartilaginous HANFS construct architecturally resembled a native intervertebral disc, with an outer annulus fibrosus (AF)-like region and inner nucleus pulposus (NP)-like region. Histological and biochemical analyses, immunohistochemistry, and gene expression profiling revealed the time-dependent development of chondrocytic phenotype of the seeded cells. Taken together, these findings suggest the prototypic potential of MSC-seeded HANFS constructs for the tissue engineering of biological replacements of degenerated IVD.

Sulfur-containing scaffold, as aubiquitous structural motif, has been frequently used in natural products, bioactive chemicals and pharmaceuticals, particularly CÀS/NÀS bonds are indispensable in many biological importantc ompounds and pharmaceuticals. Development of mild and general methods for CÀS/NÀSb onds formation hasg reat significance in modern research. Iodine and its derivativesh ave been recognizeda si nexpensive,e nvironmentally benign and easy-handled catalysts or reagents to promote the construction of CÀS/NÀSb onds under mild reactionc onditions, with good regioselectivities andb road substrate scope.E specially based on this, severaln ew strategies, such as oxidation relay strategy,havebeen greatlydeveloped and accelerated the advancement of this field. This review focuses on recent advances in iodine and its derivatives promoted hybridized CÀS/NÀSbonds formation.The features and mechanisms of corresponding reactions are summarized and the results of some cases are compared with those of previous reports. In addition, the future of this domain is discussed.