Synthesis and Characterization of Iodinated Chitosan Nanoparticles and Their Effects on Cancer Cells.

The high degree of chemical modification of the chitosan chains due to protonated amine groups allows them to react with many negatively charged surfaces as anionic polymers and cell membranes, resulting in an attractive material for medical and pharmaceutics applications. Incorporating ionic iodine (I^- and IO₃ ^-) on chitosan chains is a direct way to successfully obtain chitosan-iodine nanoparticles (CSNPs-I and CSNPs-IO₃) through ionic gelation. The nanoparticles (NPs) present a hemispherical morphology with sizes around 30-70 nm for CSNPs-I and CSNPs-IO₃, similar to chitosan NPs, in accordance with SEM and DLS techniques. The XRD characterization did not show noticeable differences in the crystallinity index (CI) for CSNPs and CSNPs-I, 48.4 and 49.3%, respectively, but for CSNPs-IO₃, the CI decreased to 43.85%. The cytotoxic effects on human tumor cells of chitosan and iodine-modified chitosan nanoparticles (CSNPs-I and CSNPs-IO₃) were evaluated for 24 h in a range from 0.15 mg/mL to 0.95 mg/mL concentrations, where CSNPs-IO₃ presented the lower viability for lung cancer A549, followed by cervical cancer HeLa cell and finally breast cancer MDA-MB-231, with a weight content of iodate ion in a range of 8.7 to 15 μg. This work presents the possibility of exploring chitosan-iodine NPs in medical applications.