Atomic force microscopy , label-free

Label-free optical techniqnes for detecting bound proteins on microarrays have been recently reviewed. The advantage of these methods over labeling methods is that the native form of the analyte is preserved. These methods include SPR, surface-enhanced laser desorption/ionization mass spectrometry (SELDI-MS), atomic force microscopy " and fiber-optic methods. 

Label-free methods. These include, among others, atomic force microscopy (AFM), quartz-crystal microbalance analysis (QCM), and SPR. 

Label-fi ee strategies provide an alternative route for circumventing the above-mentioned difficulties with respect to protein microarray detection. Currently, relatively few label-fi-ee detection methods such as mass spectrometry (MS) (2,3), surface plasmon resonance (SPR) (4) and atomic force microscopy (AFM) (5,6) are applicable to the microarray format. These label-free technologies require the use of sophisticated tools that are not available in all bioanalytical laboratories. 

M., and Notingher, I. (2011) Simultaneous Surface-Enhanced Raman Spectroscopy (SERS) and Atomic Force Microscopy (AFM) for label-free physicochemical analysis of lipid bilayers. Appl. Spectrosc., 65, 1387—1392. doi 10.1366/11-06319... 

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