Detection the specific marker of CD3 molecules of human peripheral blood T lymphocytes using SNOM and quantum dots

Scanning near-field optical microscopy (SNOM) circumvents the diffraction limits of conventional light microscopy and is able to achieve spatial resolutions substantially below 100 nm. Quantum dots (QDs) are semiconductor nanocrystals and offer several advantages over conventional organic dyes in molecular fluorescence imaging, such as higher quantum yield, excellent photostability, and a narrow, tunable, and symmetric emission spectrum. In this study a novel immunofluorescence imaging approach, which combines attributes from SNOM and QDs fluorescence labeling, is used to detect specific marker of CD3 molecules of human peripheral blood T lymphocyte. The research result shows: comparing with the conventional organic dyes of FITC, QDs have excellent photostablity and high luminance, and the specific CD3 molecules labeled with QDs were imaged at a spatial resolution of ∼90 nm, and a large number of CD3 molecules were non-uniform distribution on the surface of T lymphocyte, meanwhile a few CD3 molecules assembled to form clusters, which were possibly associated with the membrane lipid rafts. Above results illustrated that the combination of NSOM imaging and QDs labeling opens up new possibilities for single biomolecule imaging and long-term monitoring.