Surface-enhanced fluorescence

Woo MA, Lee SM, Kim G, Baek J, Noh MS, Kim JE, Park SJ, Minai-Tehrani A, Park SC, Seo YT, Kim YK, Lee YS, Jeong DH, Cho MH (2009) Multiplex immunoassay using fluorescent-surface enhanced Raman spectroscopic dots for the detection of bronchioalveolar stem cells in murine lung. Anal Chem 81 1008-1015... 

The droplet detection methods described in this entry include fluorescence, surface-enhanced Raman scattering (SERS), electrochemistry, capacitive, and mass spectrometry. The integration of different detection approaches into the microfluidic droplet device typically involves MEMS and optics technologies. Several methods have been employed to address the integration of detection components with the droplet operation unit however, the task of maintaining overall system functionality remains a challenge. As a result, most of these methods are significantly sophisticated. Trends and issues associated with each detection method are presented. 

J. Qian, L. Jiang, F. Cai, D. Wang, S. He, Fluorescence-surface enhanced Raman scattering co-functionalized gold nanorods as near-infrared probes for purely optical in vivo imaging. Biomaterials 32, 1601 (2011)... 

The commercially available dicyanomethylene squaraine dye Seta-670-mono-NHS showed extremely low blinking effects and good photostability when used in single-molecule studies of multiple-fluorophore labeled antibodies [113]. Seta-670-mono-NHS and Seta-635-NH-mono-NHS were covalently labeled to antibodies and used in a surface-enhanced immunoassay [114]. From the fluorescence intensity and lifetime changes determined for a surface that had been coated with silver nanoparticles, both labeled compounds exhibited a 15- to 20-fold... 

Bjemeld E.J., Foldes-Papp Z., Kail M., Rigler R., Single-molecule surface-enhanced Raman and fluorescence correlation spectroscopy of horseradish peroxidase, J. Phys. Chem. B 2002 106 1213-1218. 

Fort E, Gresillon S (2008) Surface enhanced fluorescence. J Phys D Appl Phys 41 013001... 

The extremely small cross sections for conventional Raman scattering, typically 10 111 to 10-25 cm2/molecule has in the past precluded the use of this technique for single-molecule detection and identification. Until recently, optical trace detection with single molecule sensitivity has been achieved mainly using laser-induced fluorescence [14], The fluorescence method provides ultrahigh sensitivity, but the amount of molecular information, particularly at room temperature, is very limited. Therefore, about 50 years after the discovery of the Raman effect, the novel phenomenon of dramatic Raman signal enhancement from molecules assembled on metallic nanostructures, known as surface-enhanced Raman spectroscopy or SERS, has led to ultrasensitive single-molecule detection. 

Alternatively, various analytical methods based on SPR phenomenon have been developed, including surface plasmon field-enhanced Raman scattering (SERS) [7], surface plasmon field-enhanced fluorescence spectroscopy (SPFS) [8-11], surface enhanced second harmonic generation (SHG) [12], surface enhanced infrared absorption (SEIRA) [13], surface plasmon field-enhanced diffraction spectroscopy (SPDS) [14-18], Most of these methods take advantage of the greatly enhanced electromagnetic field of surface plasmon waves, in order to excite a chromophoric molecule, e.g., a Raman molecule or a fluorescent dye. Therefore, a better sensitivity is expected. 

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