A pH-responsive bioassay for sensitive colorimetric detection of adenosine triphosphate based on switchable DNA aptamer and metal ion–urease interactions

Abstract

A facile and economic colorimetric strategy was designed for ATP detection by rationally using urease, a pH-responsive molecule, and a metal-mediated switchable DNA probe. By utilizing metal ions as a modulator of urease activity, the concentration of ATP is translated into pH change, which can be readily visualized by naked eye. An unmodified single-stranded DNA probe was designed, which consists of a target binding sequence and two flanked cytosine (C)-rich sequences. This C-rich singlestranded DNA can form a hairpin structure triggered by Ag + ions via C-Ag +-C base mismatch. Upon introduction of ATP, Ag +coordinated hairpin DNA structure will be broken and release the included Ag + , thus inhibiting the activity of urease. Conversely, urease can hydrolyze urea and raise pH value of the solution, resulting in the color change of the sensing solution. The proposed assay allows determination of ATP as low as 1.6 nM and shows a satisfactory result in human serum. Because of simple operation and low cost of this method, we believe it has a potential in point-of-care (POC) testing in resource-limited areas.

Metal Ion‐Mediated Optical Biosensors with Signal Amplification: Recent Advances

“…[117] The colorimetric signal resulted from pH change allowed for an LOD of 11 nM DNA. This principle also was used to construct colorimetric assays for the detection of adenosine triphosphate, [118] and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants by Li et al [119] To further improve the sensitivity, Luo, Li et al combined the CÀ Ag + À C/urease system mentioned above with CHA DNA reaction, and achieved the colorimetric detection of human immunodeficiency virus gene (HIV DNA) with an LOD of 7.8 nM. [120] In another work, Deng et al coupled the CÀ Ag + À C/ urease system with the toehold-mediated strand displacement.…”

“… [117] The colorimetric signal resulted from pH change allowed for an LOD of 11 nM DNA. This principle also was used to construct colorimetric assays for the detection of adenosine triphosphate, [118] and severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) variants by Li et al [119] …”

Dual Signal Amplification by Urease Catalysis and Silver Nanoparticles for Ultrasensitive Colorimetric Detection of Nucleic Acids

“…Therefore, chemical labeling of urease was used to develop colorimetric biosensors. ,− It was reported in early years that less than 10 equiv of Ag + could completely inactivate the urease activity. , The intense inhibition is resulted from the binding of Ag + to thiol and amine groups near the enzyme active site. Until recently, this inhibition was used to construct label-free nucleic acid biosensors for the detection of cytosine-cytosine (C–C) single nucleotide polymorphisms, nucleic acids, , and adenosine triphosphate . The key of these homogeneous biosensors lies in the isolation of Ag + by C–C mismatches or the release of Ag + from C–Ag + –C mismatched base pairs.…”

“…Until recently, this inhibition was used to construct label-free nucleic acid biosensors for the detection of cytosine-cytosine (C−C) single nucleotide polymorphisms, 27 nucleic acids, 34,35 and adenosine triphosphate. 36 The key of these homogeneous biosensors lies in the isolation of Ag + by C−C mismatches or the release of Ag + from C−Ag + −C mismatched base pairs. The sensitivity and selectivity need to be further improved due to the following reasons.…”