关键词: 布朗运动, 纳米介电泳, 药物洗脱支架, 载药纳米微粒

Abstract: A novel drug-loading method using dielectrophoretic self-organization is proposed to solve the local drug-loading of intravascular stents studded with microprobes. Based on dielectrophoretic assembly mechanism, the dimensionless dielectrophoretic force and the governing equation of motion for a particle, the drug-loading model of intravascular stents by dielectrophoresis is built for finite element analysis of the dielectrophoretic force distribution and the motion trajectories of particles in the problem space. The influence of the relative particle/electrode position and Brownian motion on the assembly efficiency is also discussed. It is proved that the assembly scheme using dielectrophoresis is feasible in theory. Finally, upon the results of the simulation, theoretical predictions of the particle response under the electric fields are experimentally confirmed by the drug-loading testing platform. Results show that for 4.4 mm latex beads suspended in de-ionized (DI) water, when the value (peak-to-peak) of the applied voltage is 10 V and the AC frequency is in the range of 0.1～1.0 MHz, the particles begin to move towards the electrodes drived by positive dielectrophoretic force, and when the AC frequency is 500 kHz, the motion rate of particle reaches the highest level.

Key words: Brownian motion, Drug-eluting stents, Drug-loading nanoparticles, Nano-dielectrophoresis