Branch-Migration Based Fluorescent Probe for Highly Sensitive Detection of Mercury

Abstract

Detection of heavy metals is of great importance for food safety and environmental analysis. Among various heavy metal ions, mercury ion is one of the most prevalent species. The methods for detection of mercury were numerous, and the T-Hg-T based assay was promising due to its simplicity and compatibility. However, traditional T-Hg-T based methods mainly relied on multiple T-Hg-T to produce enough conformational changes for further detection, which greatly restrained the limit of detection. Hence, we established a branch-migration based fluorescent probe and found that single T-Hg-T could produce strong signals. The sensing mechanism of our method in different reaction modes was explored, and the detection limits were determined to be 18.4 and 14.7 nM in first-order reaction mode and mixed reaction mode, respectively. Moreover, coupled with Endonuclease IV assisted signal amplification, the detection limit could be 1.2 nM, lower than most DNA based fluorometric assays. For practicability, the specificity of our assay toward different interfering ions was investigated and detection of Hg in deionized water and lake water was also achieved with similar recoveries compared to those of atomic fluorescence spectrometry, which demonstrated the practicability of our method in real samples. Definitely, the proposed branch migration probe would be a promising substitution for current DNA probes based on recognition of multiple T-Hg-T and we anticipate it to be widely adopted in food and environmental analysis.

Design and Synthesis of Dipeptidomimetic Isocyanonaphthalene as Enhanced-Fluorescent Chemodosimeter for Sensing Mercury Ion and Living Cells

“…Fluorescent sensors based on small molecules, in particular, have significant advantages such as their exquisite and noninvasive size, high sensitivity, selectivity, and fast response time. To date, numerous fluorescent Hg 2+ ( Chen, et al, 2015 ; Kim, et al, 2012 ) probes have been reported based on varieties of fluorophore like Rhodamine ( Bera, et al, 2014 ; Chang, et al, 2018 ; Su, et al, 2017 ; Tang, et al, 2017 ; Zhao, et al, 2010 ), BODIPY ( Hatai, et al, 2012 ; Lu, et al, 2009 ; Yoon, et al, 2005 ), Coumarin ( Sie, et al, 2017 ; Puthiyedath and Bahulayan, 2018 ), Schiff base ( Chen, et al, 2018 ; Duan, et al, 2019 ; Sarkar, et al, 2016 ; Wang, et al, 2018b ; Wang, et al, 2018d ; Zhang, et al, 2017 ), AIE luminophore ( Chen, et al, 2017 ; Selvaraj, et al, 2021 ; Wang, et al, 2018a ), Peptide-based benzoxazole unit ( Oliveira, et al, 2011 ; Oliveira, et al, 2013 ), etc. These probes were usually prepared either through the complexation with the multiple binding sites or through a chemical reaction with the proper functional group onto fluorescent molecules.…”

Versatile Integration of Liquid-Phase Microextraction and Fluorescent Aptamer Beacons: A Synergistic Effect for Bioanalysis

“…7 Recently, using the target-induced branch migration of complementary DNA sequences, we developed a structureswitching aptamer beacon for mercury (Hg 2+ ) detection in a FRET manner. 8 Although these FABs showed great potential in environmental analysis, commercially available FABs for biological applications are still scarce. Generally, there are two main challenges limiting the commercialization of such FABs.…”

“…A branch-migration based FAB reported in the previous work for Hg 2+ detection was selected as the model beacon to construct an integrated LPME-FAB system. 8 The principle of this FAB is also described (Scheme S1). In this design, the integrated aptamer beacon was included in the acceptor solution of FM-LPME.…”

“…For direct recognition of Hg 2+ by the FAB, the procedure described elsewhere was used with slight modifications. 8 Specifically, 2.5 μL of 5 μM FAM-labeled strand, 2.5 μL of 5 μM Dabcyl-labeled strand, and 39.5 μL of PBS (50 mM, pH 7.3) were mixed in a 200 μL polymerase chain reaction (PCR) tube. Subsequently, the PCR tube was immediately placed into a PCR instrument (Applied Biosystems, Singapore) to perform a designed PCR procedure (85 °C for 60 s, 55 °C for 60 s, 37 °C for 60 s).…”

Encapsulation and Release of Recognition Probes Based on a Rigid Three-Dimensional DNA “Nanosafe-box” for Construction of a Electrochemical Biosensor

“…Mercury ion (Hg 2+ ), one of the most hazardous pollutants, can accumulate in the human body through drinking water, thereby causing neural damage. , Currently, various techniques have been reported for Hg 2+ detection, such as atomic fluorescence spectrometry (AFS), coupled plasma mass spectrometry (ICPMS), fluorescence, , colorimetric methods, , and electrochemical techniques. , These innovative methods generally possess high selectivity and sensitivity. Among these methods, the electrochemical technique, with advantages of excellent sensitivity, simple instrumentation, relatively low cost, and rapid response time, has experienced soaring popularity in Hg 2+ assays. , Here an electrochemical biosensor based on a 3D DNB and electroactive 2D MOFs nanosheets was developed for ultrasensitive detection of Hg 2+ .…”