Label-free detection

Centrifugal microfluidics Label-based detection Label-free detection Lab-on-a-disc Optical detection Optical disc drive Spinning disc interferometry... 

The label-free detection of biomolecules is another promising field of application for SERS spectroscopy. Tiniest amounts of these molecules can be adsorbed by specific interactions with receptors immobilized on SERS-active surfaces. They can then be identified by their spectra, or specific interactions can be distinguished from unspecific interactions by monitoring characteristic changes in the conformation sensitive SERS spectra of the receptors. 

Rothmund M., Schtitz A., Brecht A., Gauglitz G., Berthel G., Graefe D., Label free binding assay with spectroscopic detection for pharmaceutical screening, Fresenius J Anal Chem 1997 359 15-22. 

Kroger K., Bauer J., Fleckenstein F., Rademann J., Jung G. and Gauglitz G., Epitopemapping of transglutaminase with parallel label-free optical detection, Biosens Bioelectron 2002 17 937-944. 

Cottier K., Wiki M., Voirin G., Gao H., Kunz R.E., Label-free highly sensitive detection of (small) molecules by wavelength interrogation of integrated optical chips, Sens. andActuat. 5.2003 91 241-251. 

The results obtained with PE multilayers as well as DNA on top of the capacitive EIS sensor could verify their feasibility as transducer for a label-free detection of adsorption, binding, and interactions of charged macromolecules. Nevertheless, our experiments do not enable us to clearly distinguish between the contributions in the signal generation from each of the mechanisms discussed in sections 7.3 and 7.4. Probably, both basic mechanisms, namely, the intrinsic charge of molecules and the ion-concentration redistribution in the intermolecular spaces or in the multilayer, affect the sensor signal by superposition. 

At the same time, however, it must be concluded that the practical development of FEDs for a label-free detection of DNA and other charged macromolecules by their intrinsic molecular charge seems to be more complicated than originally expected. Although the discussed results are highly exciting, they are rather diverse and even sometimes inconsistent. Factors influencing the DNA immobilization and hybridization detection by FEDs are ... 

D. Goncalves, D.M.F. Prazeres, V. Chu, and J.P. Conde, Label-free electronic detection of biomolecules using a-Si H field-effect devices. J. Non-Crystalline Solids 352, 2007-2010 (2006). 

MJ. Schoning, M.H. Abouzar, S. Ingebrandt, J. Platen, A. Offenhauser, and A. Poghossian, Towards label-free detection of charged macromolecules using field-effect-based structures scaling down from capacitive EIS sensor over ISFET to nano-scale devices, in Mater. Res. Soc. Symp. Proc. 915, 0915-R05-04 (2006). 

A. Poghossian, A. Cherstvy, S. Ingebrandt, A. Offenhauser, and M. J. Schoning, Possibilities and limitations of label-free detection of DANN hybridisation with field-effect-based devices. Sens. Actuators B 111, 470-480 (2005). 

K. Kerman, Y. Morita, Y. Takamura, M. Ozsoz, and E. Tamiya, DNA-directed attachment of carbon nanotubes for the enhanced electrochemical label-free detection of DNA hybridization. Electroanalysis 16,1667-1672 (2004). 

Armani, A. M. Kulkami, R. P. Fraser, S. E. Flagan, R. C. Vahala, K. J., Label free, single molecule detection with optical microcavities, Science 2007, 317, 783 787... 

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