Optimization and characterization of the photosensitive N-succinyl-N’-4-(2-nitrobenzyloxy)-succinyl-chitosan micelles

Abstract

With the copolymer micelles being widely used in the field of tumor therapy, environmental responding copolymers had gained large interest. In our previous work, we synthesized the nanovehicle N-succinyl-N'-4-(2-nitrobenzyloxy)-succinyl-chitosan micelles (SNSC) that were composed of a light-sensitive triggering group 2-nitrobenzyl alcohol on the hydrophobic block and succinyl group modified chitosan. We have demonstrated that the use of a continuous-wave diode near-infrared (NIR) laser could cleave the amphiphilic block copolymer micelles and trigger the release of their "payloads". In the present study, SNSC were further optimized and characterized by UV-visible spectroscopy, fluorescence spectroscopy and transmission electron microscopy (TEM) that was used to display the two-photon photolysis of SNSC micelles under the NIR irradiation (765nm) . Later on, laser confocal fluorescence microscopy was used to investigate the fluorescein (Ex/Em: 490/520 nm)-loaded SNSC imaging ability. As a result, the optimized SNSCs exhibited higher loading efficiency and smaller size which contributed to an improved stability, drug delivery and cell imaging abilities.