Effect of solvation on the synthesis of MOFs-based micro/nanorobots and its targeted-therapy applications

Magnetically driven mobile micro/nanorobots have a significant influence on the application anddevelopment of intelligent targeted drug delivery. However, the potential risk of biological toxicity is oneof the major problems in drug-loaded micro/nanorobot fabrication. Therefore, there is an urgent needto combine the features (high cargo-loading, low biotoxicity, and good biodegradability) of metal–organic frameworks (MOFs) with micro/nanorobot mobility. In this paper, the concept of green chemicalsynthesis is used to prepare mass-manufactured biodegradable MOF-based microrobots with lowbiotoxicity and high drug loading for the targeted treatment of cancer cells. Based on the solvationprinciple of the binary solvent system, the two-component solvent will be mixed with aprotic polarsolvents (X = DMAC, DMF, DMSO, NMP) and proton polar solvents (MeOH) to reduce original aproticpolar solvent toxicity. This can adjust the electrophilicity and polarity of the solution environment,change the configuration of organic ligands, and directly affect the nucleation and growth of MOFcrystallites. The results show that five different MOF crystal structures can be synthesized on the surfaceof microrobots. The MOFs synthesized in a DMAC/MeOH solvent system have cubic structures withgood biocompatibility and drug delivery properties. Furthermore, the magnetically actuated motion ofMOF-based microrobots with different geometries was systematically tested to obtain the bestswimming performance. Subsequently, the microrobots were guided through vascular-like microfluidicchannels and can be precisely controlled. Thus, this establishes a foundation to create mass-manufactured microrobotic systems that provide a new direction for small-scale medical robots withlow toxicity, high drug loading capacity, biodegradability, and precise motion control.