Featured Article: Chemotherapeutic delivery using pH-responsive, affinity-based release.

Doxorubicin is a chemotherapeutic drug typically administered systemically which frequently leads to cardiac and hepatic toxicities. Local delivery to a tumor has a chance to mitigate some of these toxicities and can further be mitigated by including a means of tumor-specific drug release. Our laboratory has explored the use of molecular interactions to control the rate of drug release beyond that capable of diffusion alone.

Mathematical modelling of glycosaminoglycan production by stem cell aggregates incorporated with growth factor-releasing polymer microspheres.

Systems composed of high density cells incorporated with growth factor-releasing polymer microspheres have recently been shown to promote chondrogenic differentiation and cartilage formation. Within these systems, the effects of spatial and temporal patterning of growth factor release on hyaline cartilage-specific extracellular matrix production have been examined. However, at present, it is unclear which microsphere densities and growth factor delivery profiles are optimal for inducing human mesenchymal stem cell differentiation and glycosaminoglycan production.

Experimental studies and modeling of drug release from a tunable affinity-based drug delivery platform.

An affinity-based drug delivery platform for controlling drug release is analyzed by a combination of experimental studies and mathematical modeling. This platform has the ability to form selective interactions between a therapeutic agent and host matrix that yields advantages over systems that employ nonselective methods. The incorporation of molecular interactions in drug delivery can increase the therapeutic lifetime of drug delivery implants and limit the need for multiple implants in treatment of chronic illnesses.

Chondrogenic differentiation of human mesenchymal stem cell aggregates via controlled release of TGF-beta1 from incorporated polymer microspheres.

Aggregate culture is a useful method for inducing chondrogenic differentiation of human mesenchymal stem cells (hMSC) in a three-dimensional in vitro culture environment. Conventional aggregate culture, however, typically requires repeated growth factor supplementation during media changes, which is both expensive and time-intensive. In addition, homogenous cell differentiation is limited by the diffusion of chondrogenic growth factor from the culture medium into the aggregate and peripheral cell consumption of the growth factor.