Abstract
The results of quantum dot (QD) probe preparation for multiplexed single-cell array staining and analysis are reported. By controlling the reaction temperature, time, and ratio of Cd to Se, multicolor CdSe QDs emitting fluorescence ranging from purple to red in a safer, simpler, and more convenient way than traditional methods is obtained. To detect cells using these oil-soluble QDs, they are first coated with water-soluble thioglycolic aid (TGA) so that biocompatible multiwavelength bioprobes can be obtained. QDs' surface is somewhat damaged when binding TGA to QDs is found, which results in a reduction of QDs' emission wavelength and a slight blue shift of QDs' emission wavelength after water-soluble modification with TGA. Comparison of the emission spectrum showed that it is negligible, and the fluorescent properties of QDs capped by TGA are still satisfactory. Living cells are then stained with multiplexed probes by conjugating TGA-QDs with antibodies specific to these cell antigens. Changes in fluorescence intensity can indicate change in the relative quantity of antigens expressed in the same cell caused by external stimulus, offering effective methods to multiplexed optical analysis of single cells.
Highlights
The potential application of quantum dots (QDs) as bioprobes is promising due to their quantum scale effects and special fluorescent properties
The reaction time determines the growth time of QDs sequentially affecting the diameters of QDs
We measured the emission spectrum of QDs that have reacted for 1 min, 5 min, 10 min, 30 min, and 1 h
Summary
The potential application of quantum dots (QDs) as bioprobes is promising due to their quantum scale effects and special fluorescent properties. When compared with normal fluorescent materials, QDs have advantages including long-term photostability, higher intensity, tunable size, broad UV excitation profiles, and narrower emission spectra.[1,2] These properties allow QDs to label different materials at the same time,[3,4] contributing to their usefulness as qualitative and quantitative probes for multiplexed detection.[5,6,7] QDs provide new approaches for real-time, high-sensitivity, and dynamic fluorescent imaging in DNA and protein detection as well as relevant biochips and biosensors.[8,9,10] Tumors have cellular heterogeneity, which leads to different responses to drugs and the environment as well as the failure of cancer treatment.[11,12] it is important to study cancer cells’ cellular heterogeneity. With the single-cell array, we can micropattern cells as designed; so, we can focus on the individual behaviors and their reactions to the drugs, rather than that of the cell colony. Combining single-cell arrays with QD probes, we can achieve multiplexed detection of the behaviors of individual cells and high-throughput drug screening
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