Optical characterization and in vivo assessment of charge-assembled capsules containing indocyanine green for laser-mediated diagnosis and therapy

We have developed a carrier system to encapsulate Indocyanine Green (ICG) to overcome its limitations for laser-mediated medical applications. Charge-assembled capsules with controllable size and adjustable coatings efficiently encapsulate ICG and effectively stabilize its optical properties. When encapsulated, ICG retains its pronounced light absorption and fluorescence properties in the near infrared spectral range. The capsules' in vivo circulation kinetics and biodistribution can be adjusted by coating the surface with various polymers or nanoparticles. The stability enhancement of ICG's optical properties by encapsulation within our capsule system was investigated using absorbance spectroscopy. The ability of capsules containing ICG to induce photothermolysis was demonstrated in an ex vivo tumorous tissue model. Biodistribution of capsules with different coating material and of different sizes was evaluated in a healthy mouse model. And the circulation kinetics and imaging quality of capsules with different coatings was assessed in mice using in vivo fluorescence imaging. Capsules containing ICG show promise for a variety of laser-mediated medical applications including phothothermal treatment of tumors and vascular lesions as well as fluorescence-based pulmonary imaging.