Chlorin e6-embedded starch nanogels for improved photodynamic tumor ablation

In this study, we report on a polysaccharide-based nanogel composed of starch conjugated with a photosensitizing chlorin e6 (Ce6) and hydrophilic poly (ethylene glycol) (PEG). The proposed design of the nanogel takes advantage of its hydrogel network and high oxygen-carrying capacity originated by the water-swollen and water-holding characteristics of starch. This resulted in a decrease in the auto-quenching effect and an increase in the photoactivity of Ce6 molecules inserted into starch. In addition, PEG decoration was introduced to enhance the colloidal stability of the nanogels. Our experimental results revealed that the nanogel structure of starch liked to Ce6 and PEG produced a significant level of singlet oxygen and elicited noticeable A549 tumor cell death under light irradiation, thereby suggesting their potential use in photodynamic tumor therapy.