Molecular Simulation Investigations On The Pressure-Driven Flow Characteristics Of Biomolecules In SiO₂Nanochannel

In recent years, there has been a growing interest in realizing micro-nano fluid automatic and accurate driver with the development of the biochip technology and nanofluidic lab on a chip technology, so it is very necessary to understand the fluid flow rules under nanoscale and it is a very big challenge in technique to achieving micro-nano fluid accurate drive, electrophoresis can only be used to drive charged particles in nano channels, but pressure gradients can be used to generate accurate and controlled flows in nanochannels, so this paper mainly studies the pressure driven flow characteristics of water and biomolecules in SiO2nanochannel.For studying the flow characteristics of fluid under nanoscale, experimental studies and fabrication techniques are important but, obviously, experimental studies at the atomic scale are difficult to perform, thus, molecular dynamics techniques provide the means for exploring nanoscale fluid flow that cannot be accessed by experimentThe molecular dynamics techniques has been used in this paper, firstly, the model of the SiO2nanochannel with8.5nm height is established then the biomolecules, water and ions are added into the nanochannels, and lastly the flow characteristics of biomolecules, water and ions driven by pressure in the nanochannels are simulated by using the GROMACS software with the force field of charmm27. The result shows that the sable pressure driven flow can be achieved by applying acceleration on each fluid molecules.Then the effect of wall charge density、channel height、temperare、pressure, and wall roughness on density、velocity and diffusion coefficient of water and biomolecules are studied, The results show that the wall charge density has a great influence on the fluid density distribution near wall; The effect of the channel height (6.5<h<10.5nm) and the impressed pressure on the velocity and diffusion coefficient of fluid is very drastic; the temperature has influence on the velocity and the diffusion coefficient of water, but the effect of temperature on biomolecules is ruleless; the wall roughness has a great perturbation on the fluid density and velocity near wall.The biomolecules and water driven by electrophoresis in SiO2nanochannel are also studied by using molecular dynamics, and the phenomenon of simple thermophoresis in the nanochannel are theoretical studied later, comparing with the pressure driving flow we find that:the fluid velocity and flux in pressure driven flow is the largest, and the use scope is also the largest, the fluid velocity and flux in electrophoresis is the second largest, and which in thermophoresis is the smallest.Finally, the processes of biomolecules and water freely and pressurized penetrate into SiO2nanochannel with8.5nm height are simulated in this paper, which find that:there are just a few water molecules can diffuse into nanochannels along walls under free penetration, but under pressure infiltration (α>2nm/ps2), a large number of water and biomolecules can penetration into nanochannels.