Fabrication and Visible Response of Au-TiO2 (P25) Composite Photocatalyst with Obvious Surface Plasmon Resonance Effect

2012 ◽  
Vol 465 ◽  
pp. 215-219
Author(s):  
Ying Liu ◽  
Hong Tao Yu ◽  
Xie Quan

Au-TiO2 composite photocatalysis material was fabricated by the photodeposition method. The SEM and TEM images demonstrate that Au-TiO2 NPs are with inerratic geometry and their diameters are in the range of 10 nm to 20 nm. The UV-vis spectra shows the strong peaks in 200-400 nm and near 550 nm which are attributed to the characteristic absorption peak of TiO2 and the strong surface-plasmon-resonance of Au NPs, respectively. Under visible light irradiation, the phenol degradation dynamics constant on Au-TiO2 was 0.008 min-1 which was 4 times of that on Degussa P25. The effects of Au amount on the photocatalytic capability of Au-TiO2 were also investigated.

2011 ◽  
Vol 158 (3) ◽  
pp. J53 ◽  
Author(s):  
Sy-Hann Chen ◽  
Shih-Te Yu ◽  
Yi-Ying Liou ◽  
Chang-Feng Yu ◽  
Chia-Feng Lin ◽  
...  

2018 ◽  
Author(s):  
Yong Cao ◽  
Mark T. McDermott

ABSTRACTUltrasensitive and selective detection and quantification of dopamine (DA) plays a key role in monitoring neurodegenerative diseases. However, the detection limit reported for DA detection is typically in the lower nM range. Pushing the detection limit to pM or lower for this particular target to cover the physiological levels (< 130 pM) is significant. Herein, DA DNA aptamer (DAAPT) gold nanoparticle (AuNP) conjugate is utilized to enhance the surface plasmon resonance (SPR) signal, which enables to detect and quantify DA in the femtomolar (200 fM) to picomolar range. To the best of our knowledge, this is the lowest detection limit achieved for SPR sensing of dopamine. The as-prepared 10 nm DAAPT-AuNP conjugate demonstrates strong binding affinity (Kd = 3.1 ± 1.4 nM) to the complementary DNA (cDNA) probe on gold chip. The cDNA probe is immobilized to the chip via polydopamine surface chemistry, which allows the Michael addition of any primary amine-terminated biomolecules. By adjusting the concentration of the DAAPT-AuNP conjugate, two calibration curves are generated with dynamic ranges from 100 µM to 2 mM, and from 200 fM to 20 nM, respectively. Both calibration curves have negative slopes, showing good agreement to a dose-response curve in an enzyme inhibition assay. In addition, the sensing strategy is evaluated to be specific for DA detection using a series of DA analogs and other metabolites as potential interferences.


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