Versatile Electrochemiluminescent Biosensor for Protein–Nucleic Acid Interaction Based on the Unique Quenching Effect of Deoxyguanosine-5′-phosphate on Electrochemiluminescence of CdTe/ZnS Quantum Dots

Abstract

In this paper, the efficient quenching effect of deoxyguanosine-5'-phosphate (dGMP) on anodic electrochemiluminescence (ECL) of the CdTe/ZnS quantum dots (QDs) is reported for the first time. This ECL quenching was found to be specific for free dGMP and not observed for dGMP residues in different DNA structures. The unique dGMP-based QDs ECL quenching was then utilized to develop a versatile biosensing strategy to determine various protein-DNA interactions with the assistance of exonuclease, Exo I, to hydrolyze DNA and liberate dGMP. Taking single-stranded DNA binding protein (SSB) and thrombin as examples, two novel detection modes have been developed based on dGMP-QDs ECL strategy. The first method used hairpin probes and SSB-promoted probe cleavage by Exo I for facile signal-off detection of SSB, with a wide linear range of 1-200 nM and a low detection limit of 0.1 nM. The second method exploited aptamer-thrombin binding to protect probes against Exo I degradation for sensitive signal-on detection of thrombin, giving a linear response over a range of 1-150 nM and a detection limit as low as 0.1 nM. Both methods were homogeneous and label-free without QDs or DNA modification. Therefore, this dGMP-specific QDs ECL quenching presents a promising detection mechanism suitable for probing various protein-nucleic acid interactions.

Hydrogen peroxide-triggered gene silencing in mammalian cells through boronated antisense oligonucleotides

“…The lower yield of dG Bpin was due to the generation of a side product, possibly the 8-oxo-dG analogue. 33 , 34 Of the synthesized nucleoside analogues, dT Bpin showed the best reaction yield and kinetics for H 2 O 2 -decaging. To provide further insights into the decaging mechanism, we examined the inducible reactivity of dT Bpin toward other ROS, such as tert -butyl-hydroperoxide (TBHP), hypochlorite (ClO – ), hydroxyl radical, tert -buthoxy radical, superoxide (O 2 – ), and nitric oxide.…”

Near infrared quantum dots in biomedical applications: current status and future perspective

“…Fluorescence remains one of the most powerful and versatile tools for biological research. Over the past two decades, advances in fluorescent materials have been revolutionary . Among these new materials, quantum dots (QDs) have attracted considerable interests in biomedical research for their many supreme characteristics compared to conventional fluorophores .…”

Surface-imprinted biosensors for the detection of proteins, cancer markers and viruses

“…The recognition element is responsible for selective binding of the target analytes, and the transducer produces the signal in accordance with the binding amount of the target analyte. The signal transition principle of the transducer can be based on the mass [1], optical [2,3], sound [4][5][6], fluorescence [7][8][9], electrochemical [10][11][12][13][14][15][16][17][18][19][20][21][22][23], or thermal response [24]. The recognition elements are usually biological agents which can be enzymes [25][26][27], antibodies [28][29][30], DNA [26,28,31,32], microbes [33][34][35][36][37][38][39][40][41], plant or animal cells [25,42,43], etc.…”