Synthesis Of New Core/Shell Quantumdots And Application In Biosensor

Quantum Dots (Quantum Dots, QDs) is a quasi-zero-dimensional semiconductor nanocrystals, form with small amount of atoms. Quantum Dots in three demensionals are below 100 nm, the movement of conduction electron ,holes in valence band and excitons are bounded in three-dimensional space, this results in unique physical and chemical properties which attracted attention. Synthesis of high performance of Quantum Dots and expand its application field are important in science significance and real application. Thereforce, our work focus on the preparation of high performance core-shell Quantum Dots,synergistic effect with other nano materials and application in chemical sensor and biosensor.Under optimum conditions, thioacetamide as sulfur source, glutathione as stabilizer and the rate of core: cell is 1:1, synthesis of water soluble high performance CdTe/CdS core-shell type Quantum Dots using CdTe Quantum Dots as core and then covered with wide gap CdS shell.Compared with CdTe Quantum Dots, the luminescent intensities and stability of glutathione stabilizer CdTe/CdS core-shell Quantum Dots are higher 6 times and 2 times more. In order to futher verify the performance of CdTe/CdS Quantum Dots , we detected deoxynivalenol with Qutantum Dots–based fluoroimmunoassay. For the first time ,we detected the stability of antibody by monitoring the luminescent intensities change value of Quantum Dots-antibody complex before and after imcubated with deoxynivalenol, the results showed that the antibody can remain good stability at least 7 days. The concentration of deoxynivalenol from 0 to 0.9 ng mL-1, the relative luminescent intensities has a good linear range relationship, the detection limit was founded to be 0.038 ng mL-1 with a 0.992 of the correlation coefficients(R2).The excellent photoelectric performance of Quantum Dots determines its greatly application potential. Quantum Dots combine with other emerging high conductivity materials such as grapheme-gold nanocomposite, which not only can expand the new field application of Quantum Dots, but also make up the new materials defects example for weak biophile.The hydrogen peroxide chemical sensor was fabricated by modfied grapheme-gold nanocomposite, CdTe/CdS Quantum Dots and gold nanocrystals on the gold electrodes ,and study on the synergistic effect of the three kinds of materials. The hole- electron pair structure of Quantum Dots determine its a unique electronic acceptor-donor. The hole attend to attract electronics in AuNPs, Quantum Dots is a electron acceptor receiving electronics. When attract to theπ-πunsaturated structure of G-AuNPs, Quantum Dots acts as donor pushing the electron in hole towards to G-AuNPs nanocomposite. In the transmission of electronics, pull and push activities will accelerate the electron transfer and enhance sensitivity.Based on chemical sensor, the ultrasensitive glucose biosensor was prepared by G-AuNPs nanocomposite, CdTe/CdS core-shell Quantum Dots and AuNPs. Since efficient electron transfer, the biosensor showed high sensitivity (5762.8 nA n M?1 cm?2 ), low detection limit (S/N = 3) (3×10?12 M ), fast response time (0.045 s), wide calibration range ( 1×10?11M to 1×10?8 M) and good long-term stability (26 weeks). The high performance of enzyme sensor can greatly meet the demand the measurement of noninvasive blood glucose. Uing saliva as samples , the sensor was applied to determination of human saliva samples, it shows the implantation of noninvasive blood glucose detection with satisfactory results.