Preliminary Study On The Detection Of Partical Translocation Events Through Nanopore On Fused Silica Capillary

With the rapid development of life science, life process can be investigated at single molecule and single cell level. Therefore, analytical means of single molecule resolution is required to adapt to this development. Among the numerous single molecule detection techniques, single molecule detection method based on translocation events through single nanopore is drawing more and more attention due to its simpleness and potential in DNA sequencing.In the first chapter of this paper, the development of nanopore based single molecule detection methods, the types of nanopores, the characterization parameters of the translocation event and application studies were reviewed.In chapter II, the resistance of the HF etched nanopore on fused silica capillary was measured with electrochemical workstation and the nanopore diameter was estimated based on some hypothetical geometrical models. The effect of HF etchant concentration on the initial nanopore resistance was investigated, and it was found that the initial nanopore resistance decreased with the increase of the concentration. Overetching with a voltage resulted in sudden current increase two times, and the current maintained stable between the two increases. However, post overetching of the pore without the voltage resulted in decrease of the resistance, indicating widening of the pore. Overetching provided a simple method for the regulation of nanopore diameter.In chapter III, the detection of translocation events of DNA and sulfonated polystyrene nanoparticle was conducted with the nanopore obtained by controlled etching of the fused silica capillary. The feasibility of the nanopore for the detection of translocation events of single molecule and nanoparticle was preliminary demonstrated with89nm sulfonated polystyrene nanoparticle, and it was noticed that the translocation events was observed with chips with pore resistance of about13MOhm in the buffer solutions used, indicating that the corresponding pore size is comparable to the size of the probe particle.This study showed that, the nanopore formed on the fused silica capillary is single, with which the translocation of single molecule or nanopartical could be observed. This method may be used as a basic platform for single molecule analysis based on the detection of translocation events through the single nanopore.