(129c) Determining Biocompatibility of a Chemically Modified Alginate Library through In Vivo Imaging and Histology

In vivo fluorescence imaging of cathepsin and macrophage activity was developed as a tool for understanding biocompatibility. Traditionally, biocompatibility of materials has been determined via histology which has the severe limitation in that only one time point can be examined, making kinetic observations of the interaction between the immune system and the implant improbable. Fluorescence imaging circumvents this issue by allowing observations of immune system responses in vivo. This technique also has the advantage that multiple time points can be analyzed, allowing for a more detailed understanding of the biocompatibility of a certain material. This technique has been used to study the biocompatibility of polymers subcutaneously injected in an array format in mice. Validation via histology through the use of positive and negative controls established this method as a means of observing immunological responses to biomaterials. Through surface functionalization, the phagocytitic response to different chemical groups can be ranked. A library of chemically modified alginates were synthesized and assayed for biocompatibility through this technique which allowed for rapid and complete analysis of the library.