Thermosensitive and tum or microenvironment activated nanotheranostics for the chemodynamic/photothermal therapy of colorectal tumor.

This research proposes the one-pot preparation of polydopamine (PDA) decorated mesoporoussilica nanoparticle (PMSN) for the thermal and tumor micro-environment (TME) responsive colorectal tumor therapy. The pores of PMSN were used for the Fe3+ loading. Lauric acid (LA), a phase-change ligand, was selected as a "doorkeeper" to coat the surface of Fe3+-loaded PMSN and prevent the undesired leakage of Fe3+. Bovine serum albumin (BSA) was selected as a stabilizer to endow the PMSN-Fe-LA-BSA nanopartilces (PMFLB) with colloidal stability. Under the near infrared laser, the light-sensitive PDA produced significant heat to kill the colorectal cancer cells via hyperthermia. Moreover, the heat induced the phase-change of LA and triggered the release of Fe3+, which further reacted with the endogenous H2S in the colorectal TME. After that, the Fe3+ was transformed into Fe2+, which triggered the Fenton reaction with the H2O2 in the TME and effectively generated hydroxyl radical (·OH). Finally, the Fe2+ was transformed into Fe3+, which repeatedly reacted with the H2S and produced more ·OH to enhance the chemodynamic therapy of colorectal tumor. Such a thermosensitive PMFLB which operates in synergy with the colorectal TME opens an alternative avenue for the rational design of multifunctional nano-therapeutic agents.