Electronic Thesis and Dissertation Repository


Master of Science


Medical Biophysics


Walter L. Siqueira


Some salivary proteins degrade quickly after secretion into the oral cavity, due to proteases present in the oral environment. DR9, the N-terminal domain of statherin is an example of these peptides, which sustains the activity of the original protein. Inspired by naturally occurred DR9 and the evolutionary pathway taken by proteins; we constructed novel peptides by combining the functional domains of different salivary proteins and investigated the functionality of these peptides. Our results revealed that DR9 duplication could increase its functionality and DR9 combination with RR14, the functional domain of histatin, could combine the functions of both peptides. Furthermore, we explored the possibility of using chitosan, an amino-polysaccharide, as a carrier for salivary peptides. Chitosan nanoparticles showed a significant higher killing effect compared to non-particle chitosan against Candida albicans. Moreover, chitosan nanoparticles showed a favorable killing effect in specific pHs, similar to the critical pHs in the oral cavity.