A Novel PDMS Surface Coating Method And Its Applications

Microfluidic chip is one of the most important frontier technology in the21st century, which has gone through rapid development and wide application in the biological medicine, chemistry, physics, bio informatics, and many other fields. PDMS is a promising material since its distinctive advantages, including elasticity, transparency, ease of fabrication, low cost, biocompatibility, etc., but it suffers from a severe problem that its surface is hydrophobic which results in a lot of difficulties to manipulate fluids in microchannel, and also greatly limits its wide application. Research shows that proper modification on the PDMS surface can effectively reduce the hydrophobicity, reduce nonspecific adsorption, improve the efficiency of analysis. So stable and easy-to-fabricate poly(dimethylsiloxane)(PDMS) surface coating with super hydrophilicity is highly desirable. In this paper, the research content is as follows:1. The coating film is made from dimethylmethacrylate (DMA) copolymeried with poly(glycidyl methacrylate)(GMA) by a two-step procedure and assemlied on the PDMS surface. Compared with the uncoated PDMS chip, coating film with performance of super hydrophilicity is uniform lays on the chip surface, water contact angle is decreased from120to7degrees. Hydrophilic PDMS surface are stable for at least half a year, and effectively suppress the nonspecific adsorption of biological macromolecules.2. The copoly(DMA-GMA) coating is applied to microchip electrophoresis. Two model proteins, lysozyme and ribonuclease A, are separated with high efficiency in the copoly(DMA-GMA)-coated PDMS microchip, compared with the uncoated PDMS, separation efficiency and sensitivity analysis are obviously improved.3. Another important application of the copoly(DMA-GMA) coating is cell patterning. The coating resists cell adhesion to enable cell patterning on planar surfaces, which cells can only grow on the bare PDMS surface and the modified area is left empty. Also polymer coating enables precise control of the distances between two cell populations, and is a powerful tool for study of cell-cell communications.4. The copoly(DMA-GMA) coating also is appled in construction of microfluidic chips for enterohepatic circulation which can be used to implement the enterohepatic circulation process. The chip including multiple chip units and complex flow control is coated to enhance the hydrophilicity and successfully manipulate fluid to realize the flow of the fluid in the microchannel.