Visual and Quantitative Screening of α1-Adrenoceptor Antagonists in Living Cells Using Quantum Dots

The performance of alpha(1)-adrenoceptor antagonists in living cells was assessed using quantum dots conjugated to a derivative of the alpha(1)-adrenoceptor antagonist prazosin. The optimum receptor binding condition and apparent K-d of prazosin-conjugated quantum dots was first determined, followed by application of these structures to drug screening. Total internal reflection fluorescence microscopy and flow cytometry were used to visually and quantitatively measure the affinity of five candidate drugs. The observed affinity order and the affinity coefficient K-i were consistent with previously reported values. These results suggest that this method is suitable for specific drug screening in living cells and is able to realize the displacement assay over the large ranges of dissociation constants.