Controllable Chemical Preparation Of Multicompartment Micromotors And Their Enzymatic Catalytical Self-propulsion

Inspired by natural biomolecular motors,a new type of micromotor has been prepared.These micromotors are generally defined as a new class of active colloidal particles capable of converting stored chemical energy in the surrounding medium or other forms of external energy,such as light,into autonomous swimming motion.At present,artificial micromotors are mainly constructed by organic polymeric materials,inorganic silicon materials and precious metals,and this may induce some problems to micromotors such as poor biocompatibility.In addition,most of the existing chemically powered micromotors need to be continuously supplemented with hydrogen peroxide to provide energy for the motion of micromotors.Some intermediate toxic by-products limit the wide application of micromotors.Therefore,it is urgent to develop a micromotor with good biocompatibility that can realize the effective distribution and synergy of multiple biological enzymes,which is conducive to the understanding of the enzyme-powered mechanism of micromotors and the development of more practical biomimetic systems.In this paper,enzyme-powered multicompartment micromotors with controlled size and high monodispersity were prepared based on the microfluidic technology.Through experimental investigation,it was determined that sodium alginate with a mass fraction of 0.7 wt%as the dispersed phase,and soybean oil as the continuous phase.Sodium alginate microdroplets（79.46μm～25.80μm）were prepared by controlling the flow rate of the continuous phase in the range of 1.0μL/min～11.0μL/min.The hydrogel microspheres were then obtained after cross-linking with 0.5 M Ca Cl₂.The ALG/PLGA multicompartment micromotors with 1 to 4 cores can be further prepared by the secondary emulsification with PLGA by controlling the flow rate of the continuous phase from 10.4μL/min to 1.6μL/min.When the ALG/PLGA micromotors were placed in glucose solution,it was observed that both the single-enzyme-powered ALG/PLGA micromotors and the double-enzyme-powered ALG/PLGA multicompartment micromotors could catalyze glucose to produce a local concentration gradient for self-diffusion propulsion.The prepared multicompartment micromotors can further load drugs or other functional molecules in chambers,and are expected to realize drug transport and directional release in vivo with the assistance of external physical fields.In summary,the multicompartment micromotors prepared by the microfluidic technology in this paper not only possess good biocompatibility and biodegradability,but also can effectively encapsulate a variety of biological enzymes to generate an enzyme cascade reaction,so as to realize self-propelled movement of micromotors.This has great potential value in nanomachines,nanomedicine,and drug transportation on the micro-nano scale.