Research On Movement Of Biological Particles Under The Influence Of Entropy Potential In Periodic Structure

Mechanisms to control the movement of biological particles using microfluidicsystems have been a focus of area for research into biochip technology. It is crucial tounderstand the basic principles of the characteristic degrees of freedom(DOF) ofparticle within constrained geometric structure since this can be implemented in thepractical application of bioscience especially for flexibly and precisely manipulatingmicoparticles, such as cells or DNA. Due to the fact that the DOF of thesemicroscopic particles in a microfluidic system are related to the boundary conditions,the multidimensional Brownian motion of particles in this system where the boundaryconditions are periodically changing can be simplified to one dimension. The effect ofthe periodic change in the boundary condition can be taken into consideration byintroducing entropy (or free energy), which takes into account the degeneration of thestates defined by the other coordinates. This simplification has found applications indescribing the directional migration, separation and rotation of particles due toBrownian motion as a result of geometrically periodic confinement. And itsapplication should improve our detailed understanding of diffusive transportprocesses occurring in confined media.In this paper, a physical model is derived to analyse and manipulate the Brownianparticle that is based on controlling the entropy in a microfluidic system havingperiodical structures. This dynamic mechanism is based on the Langevin equationfrom statistical thermodynamics and takes advantage of the characteristics of theFokker-Planck equation. Then the simulation analysis on a one-dimensionalsimplified model of this three-dimensional problem in terms of the correspondingeffects of entropy on the Brownian motion of particles and under different forms ofdiffusion coefficient is presented. This mechanism can be applied to manipulate biological particles inside a microfluidic system with conjoined sphericalmicrochannels which were made from optically transparent PMMA. This theoreticalanalysis is verified by performing a rapid and a simple technique for driving andseparating yeast cells within these constrained structures with narrow conjoined,spherical channels and pores where entropy effects dominate. Both numericalsimulations and experimental results show that the cause of the overdamped force isthe summation of the entropy due to the geometric boundary barrier of the confinedmedia; The motion of the particles depends on the geometrical boundary conditions ofthe microfluidic channels and the initial concentration of the diffusing material; As theexternal field force increases, a negative entropy appears at the beginning of eachperiod and it is possible to separate particles by moving some of them in the oppositedirection. Our theoretical model and experimental technique can be implemented infuture biophysics devices as part of a lab-on-chip system for the optimized design ofcellular analysis...