Indocyanine green-carrying polymeric nanoparticles with acid-triggered detachable PEG coating and drug release for boosting cancer photothermal therapy.

In order to boost anticancer efficacy of indocyanine green (ICG)-mediated photothermal therapy (PTT) by promoting intracellular ICG delivery, the ICG-carrying hybrid polymeric nanoparticles were fabricated in this study by co-assembly of hydrophobic poly(lactic-co-glycolic acid) (PLGA) segments, ICG molecules, amphiphilic tocopheryl polyethylene glycol succinate (TPGS) and pH-responsive methoxy poly(ethylene glycol)-benzoic imine-1-octadecanamine (mPEG-b-C18) segments in aqueous solution. The ICG-loaded nanoparticles were characterized to have ICG-containing PLGA core stabilized by hydrophilic PEG-rich surface coating and a well-dispersed spherical shape. Moreover, the ICG-loaded nanoparticles in pH 7.

Functionalized polymeric nanogels with pH-sensitive benzoic-imine cross-linkages designed as vehicles for indocyanine green delivery.

To expand clinical applications of indocyanine green (ICG) by overcoming its several drawbacks such as self-aggregation under physiological conditions, poor aqueous photostability, lack of target specificity and rapid renal elimination from the body, the functionalized polymeric nanogels with pH-responsive benzoic-imine cross-linkages employed as carriers for ICG delivery were developed by one-step cross-linking of the branched poly(ethylenimine)-g-methoxy poly(ethylene glycol) (PEI-g-mPEG) copolymer with hydrophobic terephthalaldehyde (TPA) molecules in aqueous solution of pH 7.4. Based on the findings of fluorescence, dynamic and static light scattering, and transmission electron microscopy measurements, the resulting polymeric nanogels exhibited a spherical structure comprising multiple hydrophobic benzoic-imine-rich microdomains covered by positively-charged PEI networks capable of holding large amounts of water, and hydrophilic mPEG segments.