| Abstract | Tissue engineering encompasses many important medical applications that pertain to the repair and regeneration of various tissues throughout the human body that have been adversely affected by disease or injury. Through combining the body's cells with synthetic scaffolds, tissue engineering promotes proliferation of cells at damaged sites. Recent advances have demonstrated that using biocompatible materials such as alginate hydrogels--polymer networks derived from brown algae--are a cheap and environmentally-friendly approach to this. Alginate hydrogels are effective because they mimic the extracellular matrix of tissues, which provides structural support to cells that comprise human tissues. One necessary modification to these scaffold materials is to load them with drugs that can facilitate healing. More complex designs can ideally deliver more than one therapeutic species simultaneously. In addition to hydrogels, drugs can also be loaded into a material known as porous silicon (pSi). pSi nanoparticles can be physically entrapped inside alginate hydrogels to create a two-system drug delivery mechanism with sustained release. This allows drugs such as growth factors, substances that stimulate cell growth, to be released at different times as the pSi and alginate hydrogel degrade with different timescales. This project entails the construction of alginate hydrogels that incorporate model dye-loaded pSi particles. The release of two dye molecules known as curcumin and rhodamine were monitored to assess the efficacy of the two-system drug delivery process. It was first found that curcumin was too hydrophobic to achieve significant loading in the pSi. Rhodamine (R6G) was found to be released from the pSi/alginate hydrogel system in a more incremental (sustained) manner over time compared to a relatively large initial "burst" release observed for the release of R6G from pSi only. Sustained release in drug delivery is important to ideally reduce the amount of drug necessary and is in contrast to a burst release where large amounts of the loaded molecules are released prior to achieving a stable release profile. Furthermore, the localization of pSi in the alginate hydrogels was achieved by inserting R6G-loaded pSi membranes into pre-gelled alginate hydrogels, which is important to control the spatial delivery of the loaded molecule from pSi. Overall, it is believed that in the long term this pSi/alginate hydrogel material can greatly benefit the field of tissue engineering by creating dual delivery platforms with more diverse control over drug release. |
