Artificially controlled degradable nanoparticles for contrast switch MRI and programmed cancer therapy.

Background: Utilizing the permeability enhancement and irreversible biomolecule denaturation caused by hyperthermia, photothermal-chemo synergistic therapy has shown great potential in clinical cancer treatment.

Purpose: The objective of this study was to provide a novel controlled drug release method to improve the efficiency of photothermal-chemo synergistic therapy.

Patients and methods: HCT116 tumor-bearing mice were selected as modal for the study of cancer theranostics efficiency. The T2 to T1 magnetic resonance imaging contrast switch was studied in vivo. Analyses of the tumor growth of mice were carried out to evaluate the tumor therapy efficiency.

Results: We developed novel artificially controlled degradable Co3 O4 nanoparticles and explored their potential in drug delivery/release. In the presence of ascorbic acid (AA), the designed nanomaterials can be degraded via a redox process and hence release the loaded drugs. Importantly, the AA, in the lack of l-gulonolactone oxidase, cannot be synthesized in the body of typical mammal including human, which suggested that the degradation process can be controlled artificially. Moreover, the obtained nanoparticles have outstanding photothermal conversion efficiency and their degradation can also result in an magnetic resonance imaging contrast enhancement switch from T2 to T1 , which benefits the cancer theranostics.

Conclusion: Our results illustrated that the artificially controlled degradable nanoparticles can serve as an alternative candidate for controllable drug release as well as a platform for highly efficient photothermal-chemo synergistic cancer theranostics.