Effective photodynamic therapy of polymer hydrogel on tumor cells prepared using methylene blue sensitized mesoporous titania nanocrystal

A novel hydrogel shell on cancer cells was prepared via in situ photopolymerization of polyethyleneglycol diacrylate (PEGDA) using methylene blue (MB) sensitized mesoporous titania nanocrystal for effective photodynamic therapy (PDT). TiO2 in this system served as an effective photosensitizer and initiator for the formation of hydrogel, also can protect the MB from being degraded into an inactive form. While MB was used as a significant photosensitive additive to improve the photochemistry effects of TiO2 and widen its optical response area to near infrared region (660–900 nm). The PEGDA hydrogel with peritumoral injectability shows competitive advantages, i.e. good biocompatibility and hydrophily, selective and minimally invasive delivery of TiO2@MB, maintaining a high PDT drug concentration for inducing tumor apoptosis, localized and sustainable release under 660 nm laser irradiation for reducing side effect. The hydrogel also could load chemo-therapy drugs, and serve as a versatile platform for multimode antitumor treatment. •A composite hydrogel was formed on tumor cells in situ photopolymerization for effective photodynamic therapy.•The hydrogel exhibited several competitive advantages: good biocompatibility and low cytotoxicity, enhanced antitumor effect, and reduced toxic and side effect.•Methylene blue (MB) can widen the optical response area of mesoporous TiO2 nanocrystals and enhance their PDT efficiency under NIR irradiation.