Analytical Chemistry: A new method for preparing click chemistry quantum dots for bio-orthogonal labeling

Background introduction.



Quantum dots are a class of classic zero-dimensional materials, which are widely used in biomedical analysis due to their excellent fluorescence properties. Recently, the research group of Professor He Zhike of Wuhan University reported on a novel method for preparing click chemistry quantum dots, and using the click chemistry quantum dots for rapid labeling of glucose oxidase and cancer cells. Related results were published in Analytical Chemistry, an international authoritative journal of analytical chemistry, with the title "Novel Method of Clickable Quantum Dot Construction for Bioorthogonal Labeling". Among them, doctoral student Mao Guobin and associate researcher Ma Yingxin, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, are the co-first authors.

(DOI: 10.1021/acs.analchem.0c03078)



02
Introduction to the main content of the research.



Professor He Zhike’s research group constructed a series of DNA functionalized quantum dots based on the complexation between phosphorothioate groups and metal ions, including aptamer-functionalized quantum dots, dual-color fluorescent quantum dots, and quantum dot beacons. In this research, using the strong complexation between metal ions and sulfhydryl groups, a one-pot method was used to prepare DNA functionalized quantum dots with azide/alkynes at one end and quantum dots at the other end. Compared with click chemistry quantum dot preparation methods such as covalent coupling and polymer wrapping, this method does not require any chemical modification process, and well maintains the excellent fluorescence properties of quantum dots, such as high quantum yield (quantum yield is about 80%), small hydrated particle size (about 10 nm) and good stability. Then, alkynyl-modified glucose oxidase (GOx-DBCO) and azide-DNA functionalized quantum dots (N3-DNA-QDs) were coupled by click chemistry. The coupling method improves the catalytic activity of glucose oxidase and also improves the stability of quantum dots. The GOx-QDs complex can be used for various modes of blood glucose detection, including fluorescence spectrum detection, naked eye visualization analysis and paper chip analysis. Due to the protective effect of GOx, the complex can be used for the analysis of actual blood glucose samples. Finally, the cycloalkynyl-DNA functionalized quantum dots (DBCO-DNA-QDs) are used for rapid and specific labeling of HeLa cells, which can achieve high efficiency on HeLa cells through the method of oligosaccharide metabolism engineering (non-natural glycosyl) Non-destructive labeling, and then click chemical reaction to achieve quantum dot labeling of HeLa cells. The method is simple, rapid and specific, and can also be used for specific labeling of bacteria, cells and viruses.

Picture example:

image

Click the schematic diagram of the synthesis and application of chemical quantum dots


03

summary.


This research proposes a fast and efficient method for preparing click chemistry quantum dots. The click chemistry quantum dots prepared by this method have excellent properties such as small hydrated particle size, high quantum yield, and good stability. N3-DNA-QDs can be used for efficient labeling of glucose oxidase, and after labeling, the stability of quantum dots and glucose oxidase is improved, and the activity of glucose oxidase is also improved; DBCO-DNA-QDs is used for HeLa cells The marking efficiency is high and the selectivity is good. The probe also has certain application prospects in the labeling of other biomolecules, such as bacteria, cells and viruses.