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Sensitive and selective detection for cancer biomarkers are critical in cancer clinical diagnostics. Here we developed a microfluidic protein chip for an ultrasensitive and multiplexed assay of cancer biomarkers. Aqueous-phase-synthesized CdTe/CdS quantum dots (aqQDs) were employed as fluorescent signal amplifiers to improve the detection sensitivity. Secondary antibodies (goat anti-mouse IgG) were conjugated to luminescent CdTe/CdS QDs to realize a versatile fluorescent probe that could be used for multiplexed detection in both sandwich and reverse phase immunoassays. We found that our microfluidic protein chip not only possessed ultrahigh femtomolar sensitivity for cancer biomarkers, but was selective enough to be directly used in serum. This protein chip thus combines the high-throughput capabilities of a microfluidic network with the high sensitivity and multicolor imaging ability offered by highly fluorescent QDs, which can become a promising diagnostic tool in clinical applications.

CdTe/CdS/ZnS corre‐shell‐shell (CSS) quantum dots (QDs) are synthesized in the aqueous phase assisted by microwave irradiation. As‐prepared CSS QDs are suitable novel fluorescent probes in biological applications because of their outstanding aqueous dispersibility, good spectral properties, excellent photostability, and favorable biocompatibility.

A novel microwave-assisted method of growth of high-quality CdTe/CdS core-shell nanocrystals in the aqueous phase is presented in this paper. The photoluminescence quantum yield (PLQY) is greatly enhanced by epitaxial growth of the CdS shell. Under optimum conditions, the PLQY of as-prepared nanocrystals reaches as high as 75% without any post-treatment. Furthermore, these investigations demonstrate that microwave irradiation is tremendously useful for fast epitaxial growth of nanocrystals due to its special characteristics. As a result, the microwave synthesis is sufficiently time-economizing (only five minutes are required) to obtain optimum amounts of CdTe/CdS core-shell nanocrystals in comparison to the conventional illumination method (several days are required). Therefore, this current research not only provides a rapid microwave synthesis for producing highly fluorescent CdTe/CdS core-shell nanocrystals, but also it presents some advantages of the microwave synthesis in comparison to the illumination method.

Water-dispersed nanocrystals with high photoluminescence quantum yield (PLQY) and narrow size distribution are desirable for a variety of bioapplications. In this report, we present a facile method assisted by microwave irradiation for rapidly synthesizing high-quality CdTe nanocrystals in aqueous phase. The PLQY of CdTe nanocrystals prepared in very short time (15 min) reaches as high as 82%, and the fwhm value is merely 27 nm meanwhile. Moreover, the PLQY is increased to a remarkable 98% after further amelioration through the illumination method. The key synthesis parameters (molar ratio of reagents, pH values, reaction temperature, and time) are fully discussed, and the optimum conditions are illuminated in this paper. In addition, the mechanism about microwave irradiation improving the quality of nanocrystals is discussed as well.

A novel method, the program process of microwave irradiation (PPMI), which commendably integrates good qualities of microwave irradiation and a programmed heating process, is presented to synthesize high-quality CdTe nanocrystals in aqueous solution. Microwave irradiation, which acts as the heating mode of PPMI, is highly favorable for a narrow size distribution and low concentration of surface defects of nanocrystals. On the other hand, two correlative processes (the first process and the second process) are utilized in PPMI to actualize the programmed heating process, which is an effective strategy to improve the quality of nanocrystals. Thus, a series (diameters approximately 2-4 nm) of highly luminescent (PLQY approximately 30-68%) CdTe nanocrystals were rapidly prepared (reaction time approximately 1-30 min) in aqueous phase through PPMI.

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A DNA-bridged strategy is used to facilely conjugate streptavidin (STV) to luminescent semiconductor quantum dots (QDs), which leads to convenient and stable QD-DNA-biotin-STV conjugates that serve as fluorescent nanoprobes for ultrasensitive detection of cancer biomarkers with a microfluidic protein chip.