Living Microalgae-Based Magnetic Microrobots for Calcium Overload and Photodynamic Synergetic Cancer Therapy.

The combination of Ca overload and reactive oxygen species (ROS) production for cancer therapy offers a superior solution to the lack of specificity in traditional antitumor strategies. However, current therapeutic platforms for this strategy are primarily based on non-targeting nanomaterials, leading to undesirable off-target side effects. Additionally, resistance to ROS and apoptosis induced by the hypoxic tumor microenvironment (TME) further limits therapeutic efficiency. Herein, a magnetic microrobot based on living Spirulina Platensis (SP), which is coated with a double layer of FeO nanoparticles (NPs) and CaCO NPs. The microrobots can accumulate in tumor regions under magnetic attraction, which produces a high-Ca environment under the acidic TME and facilitates Ca overload under ultrasound (US) stimulation. Meanwhile, sufficient oxygen (O) production by photosynthesis helps alleviate hypoxia and promotes in situ ROS production by chlorophyll-mediated photodynamic therapy (PDT), which can coordinate with Ca overload to induce cell apoptosis. With these unique properties, the SP-based microrobots offer a promising microrobotics-based strategy for in situ Ca accumulation and ROS production, contributing to a precise and effective way for cancer treatment.