Tumor Therapy Strategies Based on Microenvironment-Specific Responsive Nanomaterials.

The tumor microenvironment (TME) is a complex and variable region characterized by hypoxia, low pH, high redox status, overexpression of enzymes, and high-adenosine triphosphate concentrations. In recent years, with the continuous in-depth study of nanomaterials, more and more TME-specific response nanomaterials are used for tumor treatment. However, the complexity of the TME causes different types of responses with various strategies and mechanisms of action. Aiming to systematically demonstrate the recent advances in research on TME-responsive nanomaterials, this work summarizes the characteristics of TME and outlines the strategies of different TME responses. Representative reaction types are illustrated and their merits and demerits are analyzed. Finally, forward-looking views on TME-response strategies for nanomaterials are presented. It is envisaged that such emerging strategies for the treatment of cancer are expected to exhibit dramatic trans-clinical capabilities, demonstrating the extensive potential for the diagnosis and therapy of cancer.

Two birds with one stone: innovative ceria-loaded gold@platinum nanospheres for photothermal-catalytic therapy of tumors.

Photothermal therapy (PTT) has been widely employed in tumor treatment due to the non-invasive, highly selective, and low toxic side effects. However, the limited penetration of laser couples with the metastasis and recurrence of tumors, thus failing to eliminate them. Here, we report that ceria-loaded gold@platinum (CeO2/Au@Pt) nanospheres modified with polyethylene glycol (PEG). exhibit dual enzymatic activities for photothermal-catalytic synergistic therapy of tumors. CeO2/Au@Pt nanospheres are constructed through the loading of ultra-small CeO2 into core-shell Au@Pt nanospheres. In such a construct, Au@Pt enables targeted PTT, thanks to exceptional photothermal properties, while CeO2 nanozymes alleviate tumor hypoxia and kill tumor cells by producing highly toxic hydroxyl radicals (·OH) based on catalase- and peroxidase-like activities. Synergistic photothermal-catalytic therapy is achieved by delivering nanozymes to the tumor microenvironment (TME) coupled with PTT. This photothermal-catalytic approach that combines simultaneous exogenous and endogenous activation is a potential option for tumor co-therapy.