Micro-Nanofluidic Interface On Fused Silica Capillary And Polycarbonate Membrane For Translocation Invetigations

Development of optics, micro-electro-mechanical processing and nanotechnology makes detection of individual molecule possible. Among the various single-molecule techniques, the one based on translocation through single nanopore is especially promising technologies for rapid DNA sequencing. This approach is characterized in rapid, simple and label-free. A micro-nanofludic interface with a single nanopore is the foundation for translocation detections.In the first chapter of this paper, the methods of nanopore single molecule detection, the fabrication methods and characterization of nanopore were introduced. The factors of influencing nanopore single molecule detection were summarized, and new progress and challenges in the current research field were reviewed.In the second chapter, the resistance of the HF etched nanopore on the wall of fused silica capillary was measured with electrochemical workstation. The effect of aqueous buffer solution pH, voltage and HF etchant concentration on the nanopore resistance was investigated. In addition to this, a new micro-nano interface was prepared by integration of PDMS microchannels with polycarbonate nanopore filter. The effective contact area and the number of nanopore on the membrane interface were estimated by measuring the resistance. The test showed that the effective membrane area can be decreased to 3.0μm2, on which only small number of nanopores were confined, providing possibility for tanslocation assays.In the third chapter, the translocation of sulfonated polystyrene nanoparticle and lysozyme molecule was conducted with the nanopore interfce on the wall of the fused silica capillary and polycarbonate membrane. Furthemore, we showed that the application of a 10-fold salt gradient enabled more translocation events of nanoparticle. Priliminary translocation tests of sulfonated polystyrene nanoparticle and lysozyme molecule showed the feasibility of the nanopore on the wall of fused silica capillary and on the polycarbonate membrane for the detection of single molecule and nanoparticle of different size and charge. Compared with fused silica nanopore interface, lower voltage (1.5 V) was needed for lysozyme probe to transport through polycarbonate nanopore interface.The two different nanofluidic interfaces on fused silica capillary and polycarbonate membrane exhibited translocation characters as demonstrated by the nanoparticle and molecule probes. The fabrication procedure is simple and cost-effective, and could find applications in translocation detections.