Adv. funct. Mater.: multifunctional self-propelled micro robot for cell processing and drug transportation

A series of micro robots based on polymers, magnetic materials and silica have been developed for cancer treatment However, at present, most of the micro robots are tubular micro motors, whose entrance is easily blocked by cells, which hinders the robot's propulsion and requires complex surface functional modification Therefore, the design and synthesis of multifunctional, self-propelled micro robots for cancer targeted therapy has become a research hotspot Recently, a self-propelled superparamagnetic / catalytic microrobot (PM / Pt microrobots) was designed and synthesized by Professor Martin pumera of Prague University of Chemical Technology in Czech The core of the micro robot is iron oxide nanoparticles, and the outer layer is coated with a porous polymer shell containing Toluenesulfonyl group Through covalent connection, it can capture cancer cells and load drugs Furthermore, platinum is partially coated on the outer layer of the porous polymer shell, which can catalyze the decomposition of H 2O 2 into oxygen, enabling the micro robot to have self propulsion capability The micro robot is applied to capture and treat breast cancer cells Relevant achievements were published on adv function Mater (DOI: 10.1002 / ADFM 201804343) under the title of "cooperative multifunctional self-propelled paramagnetic microrobots with chemical handles for cell manipulation and drug delivery" Iron oxide nanoparticles were selected as the core, and the morphology of the micro robot was observed by SEM The results show that the micro robot is spherical, the particle size is about 4.3 μ m and the surface is rough (Figure 1) Figure 1 morphological representation of PM / Pt micro robot (source: adv funct Mater.) and then, the author verified its self propulsion mechanism The results show that with the increase of H 2O 2 concentration in the system, the speed of micro robot increases gradually (Fig 2a) The experimental results show that PM particles are chain like in the presence or absence of magnetic field For PM / Pt micro robots, even if H 2O 2 exists in the magnetic field environment, the micro robots are still integrated in chains; when the magnetic field disappears, they are immediately decomposed into individual (Figure 2C) The above results verify the mechanism of self propulsion power generated by the decomposition of H 2O 2 Fig 2 motion characterization of PM / Pt micro robot (source: adv funct Mater.) further, the author selected breast cancer cells (T47D cell line) to study the ability of the micro robot to capture and process tumors The results show that the micro robot can quickly capture and transport single or multiple aggregated tumor cells (Figure 3) Figure 3 Treatment of breast cancer cells by PM / Pt micro robot (source: adv funct Mater.) next, the author studied the ability of the micro robot to load drugs and transport them to tumor cells The fluorescence signal of DOX is mainly concentrated in tumor cells, and the robot shows good tumor targeting (Figure 4a-d); the cell survival experiment results show that the micro robot is non-toxic to cells under normal conditions, when there is a certain amount of H 2O 2 When the tumor cells apoptosis in a large area, it shows that the drug is effectively transported to the tumor area and has a certain therapeutic effect (Fig 4E) Fig 4 PM / Pt micro robot is used to load and transport DOX (source: adv funct Mater.) Finally, the aggregation of DOX in breast cancer cells was studied by fluorescence cell imaging The results showed that when DOX was loaded on the micro robot, the fluorescence intensity of the nucleus was much weaker than that of the control group, because the cells had apoptosis and the dye in the nucleus was free to the outside of the cell When the micro robot is not loaded with DOX, the nuclear fluorescence intensity is basically unchanged This experiment further proves that PM / Pt micro robot can be used as a self-propelled carrier to transport bioactive molecules to specific parts, which can significantly reduce the side effects of DOX treatment (Figure 5) Figure 5 Fluorescence imaging of breast cancer cells (source: adv funct Mater.) Summary: the author designed and synthesized a multifunctional self-propelled superparamagnetic micro robot, which can quickly and effectively capture and transport tumor cells; at the same time, the micro robot can effectively kill tumor cells by loading anti-tumor drugs, which is beneficial for The transport and accurate release of therapeutic drugs have important guiding significance.