Pyrene-Labeled and Quaternized Chitosan: Synthesis, Characterization, and Its Potential Application for Fluorescently Trackable Nucleic Acid Delivery into Cells

A chitosan derivative (Pyr-CS-HTAP)having pyrene (Pyr)and N-[(2-hydroxyl-3-trimethylammonium)] propyl (HTAP)unitsconjugated at C6 and C2 positions, respectively, was synthesized andcharacterized. Dynamic light scattering and scanning electron microscopyrevealed that Pyr-CS-HTAP self-assembled into spherical nanoparticleswith a hydrodynamic diameter of 211 & PLUSMN; 5 nm and a & zeta;-potentialof +49 mV. The successful binding of Pyr-CS-HTAP with nucleic acidwas ascertained by fluorescence resonance energy-transfer analysisand gel electrophoresis. Pyr-CS-HTAP facilitated the cellular uptakeof nucleic acid up to 99%. Co-localization analysis using fluorescencemicroscopy revealed the endosomal escape of the Pyr-CS-HTAP/nucleicacid complexes and the successful release of the nucleic acid cargoesfrom the polyplexes into the nucleus. It is strongly believed thatPyr-CS-HTAP can potentially be developed into a fluorescently trackablegene delivery system in the future.