Single-molecule detection of biomolecules by surface-enhanced coherent anti-Stokes Raman scattering

2005 ◽  
Vol 30 (9) ◽  
pp. 1024 ◽  
Author(s):  
Tae-Woong Koo ◽  
Selena Chan ◽  
Andrew A. Berlin
Keyword(s):  
Raman Scattering ◽  
Single Molecule ◽  
Single Molecule Detection ◽  
Surface Enhanced ◽  
Detection Of Biomolecules ◽  
Anti Stokes

Single-Molecule Detection of a Cyanine Dye in Silver Colloidal Solution Using Near-Infrared Surface-Enhanced Raman Scattering

1998 ◽  
Vol 52 (2) ◽  
pp. 175-178 ◽  
Author(s):  
Katrin Kneipp ◽  
Harald Kneipp ◽  
Geurt Deinum ◽  
Irving Itzkan ◽  
Ramachandra R. Dasari ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Single Molecule ◽  
Near Infrared ◽  
Colloidal Solution ◽  
Single Molecule Detection ◽  
Cyanine Dye ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Anti Stokes

Single-molecule Raman spectroscopy of a cyanine dye in aqueous silver colloidal solution with the use of surface-enhanced Raman scattering at near-infrared excitation (NIR-SERS) is reported. A characteristic Poisson distribution of SERS signals due to the Brownian motion of single dye molecule-loaded silver particles reflects the probability of finding 0, 1, or 2 1,1'-diethyl-2,2'cyanine (PIC) molecules in the probed volume during an actual measurement and is evidence that single-molecule detection by SERS has been achieved. Spectra measured in 1 s collection time with 100 mW nonresonant 830 nm excitation provide a clear “fingerprint” of a single PIC molecule by showing its typical Raman lines between 700 and 1700 cm−1. Single-molecule Raman signals are also detected for the first time at the anti-Stokes side of the excitation laser. Effective Raman cross sections for PIC of ∼10−16 cm2 per molecule can be inferred from the ratio between “pumped” anti-Stokes and Stokes signals.

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