| Summary: | 博士 === 國立臺灣大學 === 化學研究所 === 96 === The global transmission of avian influenza to human beings has recently raised tremendous attention of public health. It is important to have an effective warning system for prophylaxis and diagnosis of the influenza virus. Polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) are commonly used in biomedical analysis, but these methods often require several hours and tedious sample preparation. Herein, we report several novel, sensitive, and rapid methods to solve these problems.
In the first method, HA-specific antibodies were conjugated on magnetic nanoparticles, and used effectively to extract H5N2 virus from an allantoic fluid. After digestion by trypsin, the captured HA protien on magnetic nanoparticles can be detected directly by SDS-PAGE and protein identification was confirmed by LC-MS/MS. To speed up the analysis, the virus–magnetic nanoparticle complexes were directly analyzed by MALDI-TOF mass spectrometry, and the HA protein of H5N2 virus was identified from the mass spectroscopy.
In the second method, silicon nanowire field-effect transistors (SiNW-FETs) modified with antibodies were used as a real-time biosensor to detect H5N2 virus. SiNWs doped with boron (a p-type semiconductor) were applied as a sensing element. The wires were modified with appropriate antibodies, and used to recognize H5N2 virus. An electrostatic gating effect due to the interactions between H5N2 virus and antibodies on the surface of SiNW-FETs caused a variation of electric conductance inside the SiNW-FETs, thus providing a quick and sensitive detection of H5N2 virus.
Magnetic nanoparticles can act as magnetic relaxation switches by changing the spin-spin relaxation time (T2) of the surrounding water molecules. The antibody encapsulated magnetic nanoparticles will aggregate upon interactions with the target antigen in solution. A method for detection of H5N2 virus is thus designed via the target-induced self-assembly of magnetic nanoparticles.
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