| Cardio-cerebrovascular diseases and malignant tumors are the leading causes of death for patients,and they have always been difficult problems solved by the medical engineering community.Micro-nano robots can penetrate blood vessels or biological tissues to target drugs to lesions to achieve precise treatment,which is a hot spot of current research.In view of the challenges of the existing active targeted drug delivery microrobots with limited maneuverability and limited load capacity,and difficult to control the accuracy of posture,this subject designed a flexible liquid metal micromanipulator with high maneuverability,large load capacity,high adaptability and low biological toxicity.The robot,which can be driven by an external energy field to achieve precise navigation,positioning,attitude adjustment,and drug release in a three-dimensional space,has great clinical value.First,a new magnetic modification method for liquid metal based on gallium was proposed,which laid the foundation for the preparation of liquid metal microrobots for active targeted drug delivery.Based on the copper-gallium wetting mechanism,copper-iron alloy nanoparticles(Cu-Fe NPs)were successfully mixed into the liquid metal to prepare a low-viscosity,magnetically functional liquid metal.Magnetic,realizing precise control of liquid metal by external electric/magnetic field.The effects of different parameters of Cu-Fe NPs on the electric driving performance,magnetic driving performance and fluidity of functional liquid metals were tested.In addition,design experiments have verified the electromagnetic coupling drive performance of functional liquid metals,and for the first time achieved reverse gravity climbing of liquid metals under electromagnetic coupling.Secondly,a new precise and controllable liquid metal droplet microrobot(LMDR)preparation method for active targeted drug delivery was proposed,which laid the foundation for implementing in vitro/living targeted drug delivery.Based on the copper-gallium wetting mechanism,a drug-loaded functional frame was successfully implanted inside the liquid metal droplet to prepare a liquid metal droplet microrobot.The prepared liquid metal droplet microrobot has an appearance similar to that of a liquid metal droplet,but under the control of an external energy field(electrical/magnetic),it can realize self-deformation through a slit,3D jumping,attitude adjustment,and self-assembly/self-assembly.Various 3D maneuvers such as disintegration and controlled drug release.Further,this paper analyzes the motion mechanism of the liquid metal droplet microrobot under the action of external fields from the theoretical and experimental aspects,from the density ratio of the load functional frame to the liquid metal,the load mass,the volume of the liquid metal,and the strength of the external driving field.Experimental verification was performed in multiple dimensions,and the optimal conditions for the preparation of liquid metal droplet micro-robots were finally given.Finally,an experimental platform was constructed to study four kinds of complex motion control of liquid metal droplet micro-robots and analyze their dynamic models.On this basis,a conceptual proof-of-concept experiment was successfully carried out on the liquid metal droplet micro-robot targeted transport and release of a chemical indicator.Furthermore,based on the microfluidic chip,a mouse breast cancer in vitro simulation environment was constructed,and the liquid metal droplet microrobot was loaded with a broad-spectrum anticancer drug doxorubicin,and the mouse breast cancer 4T1 cancer in vitro simulation environment was successfully implemented.The targeted drug delivery experiment of cells successfully killed almost 100%of the in vitro microfluidic simulated tumor environment,and through control experiments,the low biological toxicity of the liquid metal droplet microrobot was confirmed,and the liquid metal droplet microrobot was demonstrated Great application potential in active targeted cancer treatment. |
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