Methods to better match tissue developed in vitro to characteristic in vivo features are highly desirable in regenerative medicine. Our client required a biomaterial for 3D cell culture to improve the phenotype of chondrocytes differentiated from perivascular stem cells in the context of cartilage engineering. Using traditional methods, differentiation of stem cells to chondrocytes in vitro usually results in a hypertrophic phenotype. Often this is evident by the over expression of type X collagen which is typically not expressed in the superficial (articulating)-zone of hyaline cartilage, but characteristic of chondrocytes in more bone-like tissue / deep zone.
Our client’s study compares phenotype characteristics between pericytes, obtained from human adipose tissue, differentiated in 3D culture using Biogelx hydrogel technology and with the more widely used chemical induced method for chondrogenesis. In Biogelx gels tuned to a stiffness similar to that reported for chondrons (15.5 kPa), they found that the phenotypic characteristics of chondrocytes cultured in Biogelx hydrogels were more desirable than those achieved using chemical induction methods. These include significantly higher levels of type II collagen (over type X collagen) being observed when pericytes undergo chondrogenesis in the Biogelx hydrogel, and that there is also a balanced expression of collagen relative to aggrecan production, a feature which was biased toward collagen production when cells were cultured with induction media.
The study highlights not only how material and chemical alterations in the cellular microenvironment have wide ranging effects on resultant tissue type, but that Biogelx hydrogels can provide results in in vitro studies that are more relevant to an in vivo scenario.
Alakpa, E., V., Jayawarna, V., Burgess, K., V., West, C. C., Péault B., Ulijn, R. & Dalby, M., J. (2017) Improved hyaline cartilage phenotype from pericytes differentiated using tunable peptide hydrogels. Scientific Reports, 7, article 6895.
“Having a biomaterial system that is able to influence phenotypic expression is hugely desirable as a replacement for chemically-induced differentiation methods, as being able to match the features of tissue produced in vitro to the required structure of the lost tissue is key for tissue engineering applications. The Biogelx hydrogels were easy to work with, cells grew well within them forming desired aggregates over time, and they offered the ability to tune the physical properties of the cells microenvironment to achieve the required results.”