Indocyanine Green-Glycogen Conjugates for Near-Infrared-Triggered Photothermal Cancer Therapy

Photothermal reagents sensitive to near-infrared (NIR) light are promising imaging agents and therapeutics for anticancer applications because of the deep tissue penetration of NIR light, allowing for spatiotemporal control over the therapeutic activity, with minimal damage to normal tissues. Herein, a new class of NIR-sensitive biopolymer-based nanoparticles is presented by covalently conjugating indocyanine green (ICG) onto the surface of naturally occurring glycogen nanoparticles. The resulting ICG-glycogen conjugates exhibit a markedly enhanced aqueous stability in comparison to free ICG molecules. Furthermore, an efficient light-to-heat conversion is enabled by ICG-glycogen conjugates, as evidenced by the elevated temperatures of their aqueous solutions upon exposure to NIR light. Critically, ICG-glycogen conjugates are capable of cell internalization, and under NIR irradiation the effective eradication of breast cancer cells, demonstrating their potential in photothermal therapy for cancer. This study presents a new class of near-infrared-sensitive nanoparticles by conjugating indocyanine green (ICG) to glycogen. The resulting ICG-glycogen conjugates imbue the ICG with two critical properties otherwise not inherent to the free ICG: 1) significantly enhanced hydrolytic stability; 2) improved cellular uptake. These unique properties of ICG-glycogen conjugates lead to an improved NIR-triggered anti-cancer performance in breast cancer cells.image

Automated summary

This study presents a new class of near-infrared-sensitive nanoparticles by conjugating indocyanine green (ICG) to glycogen. The resulting ICG-glycogen conjugates imbue the ICG with two critical properties otherwise not inherent to the free ICG: significantly enhanced hydrolytic stability and improved cellular uptake. These unique properties of ICG-glycogen conjugates lead to an improved NIR-triggered anti-cancer performance in breast cancer cells.