Fabrication Of Nanopen And Its Application In Detection Of Bovine Serum Albumin Translocation

The detection of biomolecules is one of the basic research techniques in genomics,proteomics,glycemics and other biology related fields,of which the progress will promote the medicine,pharmacy,biology profoundly.The advance in those fields could improve people's quality of life,medical level,industrial production and some other aspects.Therefore,technique of biomolecule detection is of great value and significance to be developed.In this thesis,we successfully developed a hybrid nanoelectrode(called "gold nanopen" in this thesis)integrated a nanopore and a gold nanoelectrode simultaneously for biomolecule detection.One of the most important features of nanopen is that it could be used to combine the nanopores detection technology and the tunnel current detection technology.In this thesis,we mainly focus on the application of nanopen for biomolecule detection.The main contents of this thesis are as follows:1.First to briefly introduce the historic background of nanopore and basic knowledge of nanopores,mainly from the categories of nanopores,applications.And the following part is the categories,preparation methods,related parameters and applications of the nanopipette(known as glass nanopore or nanocapillaries).2.Secondly,the preparation method and process of nano-pen are described in detail.In this paper,nanopipettes used in this paper were made by laser puller.Then the double-channel nanopipettes were used to prepared carbon nanopen using butane pyrolysis,and the gold nanopen was prepared then by potentiostatic electrochemical deposition.The gold nanopen was used as a probe in conductance measurement of 1,4-butanediamine using fixed junction method,and the result turns out that the conductance of,4-butanediamine was 0.3?S,which proving that gold was deposited on the carbon electrode and the gold nanopen could be used as a probe in tunnelingcurrent detection.3.Then the process of construction and testing of ionic current detecting equipment was described.Home-built equipment are used to detect translocation of 40 nm × 13 nm gold nanorods and ?-DNA.The blockage current due to the translocation of GNRs is increased with the increasing bias,however,the duration of the signal didn't show obvious difference.Three types of conformation(folded,half-folded,unfolded)when ?-DNA translocating was observed which validate ability of equipment for biomolecules detection.4.Translocation features of bovine serum albumin(BSA)molecules were detected with home-built equipment and gold nanopen under the condition of different bias,different electrolyte concentration and different p H.Under different bias,the amplitude of signals due to BSA molecules translocation is increased with increasing bias,while the duration didn't show an obvious difference.Worth to be mentioned,the threshold voltage of which the BSA translocation signal could be observed is 0.6 V.Under different concentration,the amplitude of blockage current is higher when measuring in a high-concentration electrolyte,which is beneficial to detect the faster translocation process.Under different p H value,at p H 2.5,the amplitude and duration of the translocation signal of BSA molecules increased compared with that of the translocation signal at p H 8.0,which was due to the fact that the conformation of BSA molecules changed to the fully expanded conformation under the condition of p H 2.5,which was different from that of molecules at p H 8.0.This result indicated that the nanopen could discriminate different conformations of BSA molecules,which proved that the nanopen could be used in biomolecules detection.This thesis is the first step in the development of nanopen detection technique.By modifying specific molecules which can interact with analyte,it can help reduce the translocation speed of analyte.Combining with tunneling current detecting technique is the next step,which can simultaneously detect the biomolecule by two means: ionic current and tunneling current.This may improve the accuracy of the detection and dig more information from once biomolecule detection.