Sulfur Compounds Piezoelectric Immunosensor For The Self-assembly Technology

Piezoelectric sensing technique has been applied to many fields,including analytical chemistry,life science,environmental monitoring and surface sciences because of it's small size,high sensitivity,simplicity,low power consumption and broad sensing spectrum. Piezoelectric immunosensors possess high selectivity provided by antibodies or antigens and sensitivity response directly to the mass change of proteins. Immobilization technologies of biomolecules are of paramount importance in order to preserve their biological activity. There are mang immobilization methods we can use directed or indirected. The use of SAM in various fields of research is rapidly growing,a interesting work is based on the strong absorption of disulfides (R-S-S-R),sulfides (R-S-R) or thiols (R-SH) on the gold surface. While integrating with the new improving in biomolecule immobilization,this thesis presents a theoretical and applied studies of several new piezoelectric immunosensors based on the Au-S SAMs. The main works are summarized as follows:1. A novel protein immobilization approach based on mercapto-PHA SAM for piezoelectric immunosensors has been proposed,which is formed by coupling mercaptoprorionic acid (MPA) to Poly (allylamine hydrochloride) (PHA) via 1-ethyl-3-(3-dimethylamino-propl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). After self-assembling a mercapto-PHA SAM on the gold electrode of the quartz crystal,the goat-anti-IgM antibody is immobilized via cross-linking with glutaraldehyde. The detecting linear range of the piezoelectric immunosensor employing mercapto-PHA SAM is 0.66 - 26.4 ug/mL.2. A novel protein immobilization approach for piezoelectric immunosensors based on the SAM of derivative AA has been proposed,which is formed by coupling merca ptoprorionic acid (MPA) to Alginic acid sodium salt via EDC and NHS. (1) the Tr antibody is immobilized via EDC and NHS. Comparing with the MPA SAM method,this new approach shows greater frequency response and high sensitivity. The detecting linear range of the piezoelectric immunosensor employing derivative AA SAM is 0.08 - 25.7 ng/mL. (2) The piezoelectric immunosensorwas used for the detection of C3 in human serum in the range of 0.072 - 21.6 Hg/mL. It demonstrates that the results of clinical samples by this developed method are identical to those by the ELISA method.3. A novel piezoelectric immunosensor for the Antitrypsin is developed based on the self-assembled menbrane (SAM) of Cystamine. After self-assembling a Cystamine SAM on the gold electrode of the quartz crystal,the a,-AT antibody has been immobilized via cross-linking with glutaraldehyde. This approach shows satisfactory frequency response and sensitivity. The detecting linear range is 0.23 -23.9ng/mL.