Poly N-isopropylacrylamide (NIPAM) microgel particles are unique because they are able to change their volume in response to changes in temperature and pH. When co-polymerized with acrylic acid, they may be surface-functionalized with desired biomolecules and used as multi-functional biomaterials. In this research, NIPAM-co-acrylic acid microgel particles were surface-functionalized with albumin bovine serum (BSA) via carboiimide crosslinking chemistry. To verify that the bioconjugation reaction worked, the MicroBSA assay (Invitrogen) was used to quantify concentration of protein molecules that had been crosslinked to the microgel surfaces. The hypothesis for this research is that protein concentration should increase with increasing initial protein concentration. The hypothesis was verified by carrying out the MicroBSA assay and measuring the absorbance of bioconjugated microgel particles against a standard curve of known BSA concentrations. The results of the experiment show some evidence of protein bioconjugation but showed little variation with increasing BSA concentration. The reported results indicate that further conjugation experiments must be carried out, to optimize the results obtained from the MicroBSA assay. Upon completion, the material properties and interfacial properties of the microgel particles on surfaces will be invested, as a part of future work.
