Presenter: Esther Aurelie Mozipo – Biochemistry
Faculty Mentor(s): Veronica Spaulding, Marian Hettiaratchi
Session: (In-Person) Poster Presentation
Large bone defects have difficulty healing without intervention, leading to nonunion fractures.1 Hydrogels are a promising solution to this problem due to their biocompatibility and potential as a drug delivery vehicle. Hyaluronic acid (HA) is a naturally-occurring polymer that can be functionalized to create a hydrogel. HA exists in our bodies in different molecular weights, which are involved in different biological processes.2 I investigated whether varying the molecular weight of the HA could have an effect on the properties of the HA hydrogel and cellular responses. HA hydrogels were synthesized via a hydrazone click reaction of aldehyde-modified HA(HA-Ox) and carbohydrazide-modified HA (CH-HA). The degree of modification (DOM) of the HA was determined using 1H NMR spectroscopy. The effect of HA on osteogenesis was determined by measuring alkaline phosphatase (ALP) activity of C1C12 skeletal myoblasts in HA solutions. The DOM of CH-HA at 40 kDa, 100 kDa, 700 kDa, and 1500 kDa was 25.4, 20.4, 7.8, and 0%, respectively while the DOM of HA-Ox at the same molecular weights was 13.7%, 12.6%, 7.0%, and 3.6%, respectively. C2C12 cells grown in unmodified 40 kDa, 100kDa, 700kDa, and 1500 kDa HA exhibited ALP activity comparable to C2C12 cells cultured in media only. However, in the presence of bone morphogenetic protein 2 (BMP-2), an osteoinductive protein, the 700 and 1500kDa HA inhibited BMP-2 induced ALP activity when compared to the 40 and 100kDa HA.