Tetra(4-carboxyphenyl)porphyrin-grafted chitosan fluorescent biopolymer: Synthesis, characterization, high DNA loading capacity and gene delivery

Cationic polymer-based gene delivery vectors face several challenges, including low DNA loading capacity, rapid renal clearance, high toxicity due to non-degradability, and poor transfection efficiency. Chitosan offers a promising alternative due to its inherent biocompatibility, biodegradability, and low immunogenicity, but its limited solubility and moderate gene delivery efficiency restrict broader application. To address these challenges, we developed a water-soluble porphyrin-grafted chitosan (PGC) biomaterial by covalently conjugating tetrakis(4-carboxyphenyl)porphyrin (TCPP) to the amino groups of chitosan, creating a multifunctional fluorescent biopolymer. Its structural and morphological properties have been characterized by UV–vis, FT-IR, ¹H NMR, AFM, FE-SEM analysis. The PGC biopolymer exhibited a degree of substitution of 7.5% as determined by ¹H NMR. When excited at 433 nm, the PGC biopolymer showed fluorescence emission at 680 nm. It effectively loads DNA and enables enhanced gene delivery efficiency. Additionally, it demonstrated efficient cellular uptake, highlighting it as an efficient non-viral gene delivery carrier that could be useful in the delivery of cancer therapeutics.