The microRNA family shows great promise for the diagnosis and prediction of different cancers as biomarkers, in which miRNA-155 (miR155) is recognized as a biomarker for lung cancer and thus has drawn much attention. Therefore, the development of specific and accurate methods to detect miR155 has become a potential research hotspot. In this work, we presented a fluorescence resonance energy transfer (FRET) technique by utilizing core–shell CdSeTe/ZnS quantum dots (QDs) as a signal reporter and a target recycling strategy as a signal amplifier for the detection of miR155. In the presence of miR155, part of the hairpin probe (HP) immobilized onto the surface of gold nanoparticles (AuNPs)@SiO2, could hybridize with it. Then, numerous H1-AuNPs@SiO2 could be produced with the aid of exonuclease III. With the linkage of the assistant chain A2, H1-AuNPs@SiO2 combined with A1-QDs and then the fluorescence (FL) signal of QDs was quenched by AuNPs@SiO2via FRET. The more miR155 present in solution, the weaker the detected FL signal. A linear response range of 0.01 fM to 1 nM and low detection limit of 3 aM were obtained using the proposed method. Furthermore, this method showed high specificity and satisfactory recovery between 93 and 105% in real human serum samples, illustrating its great potential for practical applications.
Emerging photoelectrochemical (PEC)-type photodetectors (PDs) have attracted increasing attention due to their low-cost manufacturing and liquid-phase working environment. However, the current reported PEC-PDs still suffer from relatively poor stability during operation in harsh and complex liquid environments, which hinders their practical applications. Here, a custom PD based on the CdSe 0.9 Te 0.1 /ZnS core-shell quantum dots (CSQDs) was constructed with optimized photocurrent density ( P ph ) of 7.36 μA∙cm −2 , photo-responsivity ( R ph ) of 701 μA∙W −1 and detectivity of 1.93 × 10 8 Jones in basic electrolyte. Even in a highly corrosive acidic electrolyte, excellent photo-response performance was observed with P ph of 1.48 μA∙cm −2 and R ph of 6.88 μA∙W −1 . Strikingly, ultra-high photocurrent retention efficiency (PRE) values of 98.1 % and 74 % can be retained for measuring in 1.0 M KOH and HCl after sample stored for one month, respectively. Density functional theory calculations confirmed that the adsorption energy of CdSeTe/ZnS-OH/-H CSQDs are both weaker than CdSeTe-OH/-H QDs. This work presents a pH-universal photoactive material for PEC-PDs, and achieves one of the highest PRE values reported in PEC systems, demonstrating the enormous potential of CdSe 0.9 Te 0.1 /ZnS core/shell structure in enhancing device stability and overcoming the acid-hydrolysis problem of Cd-based materials.
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