A nanofluidic channel fabricated in fused silica with an approximately 500
nm square cross section was used to isolate, detect and identify
individual quantum dot conjugates. The channel enables the rapid
detection of every fluorescent entity in solution. A laser of selected
wavelength was used to excite multiple species of quantum dots and
organic molecules, and the emission spectra were resolved without
significant signal rejection. Quantum dots were then conjugated with
organic molecules and detected to demonstrate efficient multicolor
detection. PCH was used to analyze coincident detection and to
characterize the degree of binding. The use of a small fluidic channel to
detect quantum dots as fluorescent labels was shown to be an efficient
technique for multiplexed single molecule studies. Detection of single
molecule binding events has a variety of applications including high
throughput immunoassays.