Browsing by Subject "electrophoresis"
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Item Open Access Modeling, Fabrication, and Test of a CMOS Integrated Circuit Platform for Electrophoretic Control of On-Chip Heterogeneous Fluids: toward Particle Separation on a Custom CMOS Chip(2009) Wake, Heather AnneElectrophoresis is the migration of charged particles in a heterogeneous fluid under the influence of an electric field. This project is work toward an electrophoretic separation system on a custom CMOS chip. Modeling, fabrication, and testing of an AMI ABN 1.5 um CMOS chip for this application is discussed. The unique approach is to build the entire system using conventional CMOS integrated circuit technology, such that the separation area is fabricated on the chip with integrated control and detection circuitry. To achieve the desired functionality, a novel configuration of an electrophoresis system is implemented. In this system, instead of using only one electrode at each end of the separation area, a multitude of electrodes beneath the entire separation area are utilized, enabling better control of high electric fields using very small voltages over small areas. Electronic circuits control the position and strength of the electric field to drive the separations and to simultaneously detect the location and concentration of samples within the separation area. Ultimately, the project was successful at showing that implementing an electrophoresis system on standard CMOS is possible.
Item Open Access Non-stokes drag coefficient in single-particle electrophoresis: New insights on a classical problem(Chinese Physics B, 2019-01-01) Liao, MJ; Wei, MT; Xu, SX; Daniel Ou-Yang, H; Sheng, PWe measured the intrinsic electrophoretic drag coefficient of a single charged particle by optically trapping the particle and applying an AC electric field, and found it to be markedly different from that of the Stokes drag. The drag coefficient, along with the measured electrical force, yield a mobility-zeta potential relation that agrees with the literature. By using the measured mobility as input, numerical calculations based on the Poisson-Nernst-Planck equations, coupled to the Navier-Stokes equation, reveal an intriguing microscopic electroosmotic flow near the particle surface, with a well-defined transition between an inner flow field and an outer flow field in the vicinity of electric double layer's outer boundary. This distinctive interface delineates the surface that gives the correct drag coefficient and the effective electric charge. The consistency between experiments and theoretical predictions provides new insights into the classic electrophoresis problem, and can shed light on new applications of electrophoresis to investigate biological nanoparticles.