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. Author manuscript; available in PMC: 2011 Apr 15.
Published in final edited form as: Anal Chem. 2010 Apr 15;82(8):3383–3388. doi: 10.1021/ac9024335

Figure 2.

Figure 2

Concentration-enhanced PSA ELISA. (a) ELISA product from 96-well plates was directly injected into the microchannels. When a voltage was applied between the inlet microchannels and the side channels, the product molecules were electrokinetically accumulated and attained a high local concentration. The sensitivity of fluorescence detection was significantly enhanced in this region. (b) The concentrated FITC tracer showed similar intensities, indicating similar accumulation rate in all channels. (c) Without electrokinetic accumulation, only the top channel (corresponding to high concentration of PSA) displayed a slight increase in product fluorescence. In the accumulation region, it was easy to differentiate the difference in product fluorescence between each channel. (d) Dose response curve of concentration enhanced PSA ELISA. Square markers represent intensities with product accumulation, while cross markers represent intensities without product accumulation. Error bars indicate one standard deviation from the mean of three separate experiments. Sensitivity enhancement due to product accumulation was ~ 100 fold.