Authors: S.J. Yang, C.L. Peng, P.S. Lai, F.H. Lin and M.J. Shieh
Affilation: National Taiwan University, Taiwan
Pages: 471 - 474
Keywords: chitosan, 5-aminolevulinic acid, photochemical diagnosis, colon cancer
Photodynamic medicine is a novel approach for cancer therapy and diagonosis via different photosensitizers and suitable light source. The 5-Aminolevulinic acid (5-ALA) can be converted into protoporphyrin IX (Pp IX ) that can be utilized as a fluorescent probe for tumor detection, however, this biosynthetic pathway also can be occurred in normal flora, including E. coli, in the colon and rectum that influence the efficacy of tumor detection. In this study, 5-ALA was encapsulated in chitosan nanoparticles to prevent uptake of E. coli. This result implied that chitosan can exclude the influence of normal flora inside the gut and serves as an ideal vector of colon-specific drug delivery system. According to this concept, we designed a novel photodynamic detection system to enhance the accuracy of endoscopic diagnosis for early colorectal cancer.