A colorimetric nanobiosensor with enhanced sensitivity for detection of lead (II) in real-water samples via an adenine-cytosine mismatched DNAzyme

doi:10.1007/s11783-024-1916-0

2024, Vol. 18

Issue (12) : 156 https://doi.org/10.1007/s11783-024-1916-0

A colorimetric nanobiosensor with enhanced sensitivity for detection of lead (II) in real-water samples via an adenine-cytosine mismatched DNAzyme

Jinchuan Liu¹(

), Hang Yang¹, Huanxing Li¹, Jiancheng Wang¹, Xiaohong Zhou²(

)

¹. College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
². State Key Joint Laboratory of ESPC, School of Environment, Tsinghua University, Beijing 100084, China

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Abstract

● A colorimetric nanobiosensor with one-step was developed for Pb²⁺ detection.

● An A-C mismatched DNAzyme was designed to improve the sensitivity.

● The detection limit of 8.6 nmol/L was achieved for Pb²⁺.

● Satisfactory recoveries were achieved in various real water samples.

● An entire detection time was less than 30 min.

Facile and ultrasensitive detection of Pb²⁺ in water for remote or resource-limited environments remains challenging. DNAzyme-based colorimetric nanobiosensors have been extensively studied to regulate the assembly of functionalized gold nanoparticles (AuNPs). However, these nanobiosensors have been criticized for their low sensitivity owing to the difficulty of dissociating DNAzyme embedded in AuNP aggregates. To address this issue, we rationally designed a DNAzyme by introducing an adenine-cytosine (A-C) mismatch to strengthen the disassembly of DNAzyme-linked nanostructures. As proof of concept, a “turn on” colorimetric nanobiosensor integrated with mismatched DNAzyme and functionalized AuNPs was first developed for Pb²⁺ detection. Under the optimal detection conditions, the obtained typical calibration curve shows a detection limit of 8.6 nmol/L, with an approximately 11-fold sensitivity improvement in Pb²⁺ detection compared with unmismatched DNAzyme, and a linear response range from 10 to 300 nmol/L. This nanobiosensor demonstrated robust selectivity and satisfactory recovery rates between 86.5% and 106.4% for Pb²⁺ in spiked environmental water samples. Additionally, the detection process is user-friendly and can be completed within 30 min, requiring only a simple water sample addition step. Considering the extensive applications of DNAzyme in conjunction with nanoparticles, this study provides a valuable reference for designing other DNAzyme-powered nanoparticle assemblies in biosensing systems.

Keywords Trace lead(II) ions Modified mismatched DNAzyme Gold nanoparticles Colorimetric nanobiosensor Environmental water samples

Corresponding Author(s): Jinchuan Liu,Xiaohong Zhou

Issue Date: 15 October 2024

Cite this article:

Jinchuan Liu,Hang Yang,Huanxing Li, et al. A colorimetric nanobiosensor with enhanced sensitivity for detection of lead (II) in real-water samples via an adenine-cytosine mismatched DNAzyme[J]. Front. Environ. Sci. Eng., 2024, 18(12): 156.

URL:

https://academic.hep.com.cn/fese/EN/10.1007/s11783-024-1916-0
https://academic.hep.com.cn/fese/EN/Y2024/V18/I12/156

Fig.1 (a) Scheme of “turn on” plasmonic Pb²⁺ detection based on DNAzyme–AuNP disassembly. M1, M2, M3, M4, M5, M6, M7, and M8 represent sensors containing A–C mismatches at different positions; (b) cleavage kinetics of DNAzyme–AuNP constructs. Error bars correspond to standard deviation (n = 3).

Tab.1 Thermodynamic properties simulation of the DNAzymes

Fig.2 Correlation between absorption ratio (A₅₃₃/A₇₀₀) for ten systems (GR5, M1, M2, M3, M4, M5, M6, M7, M8, and M2M5-DNAzyme–AuNPs) in absence and presence of 500 nmol/L Pb²⁺, respectively; SNR is the ratio of A₅₃₃/A₇₀₀ with Pb²⁺ to that without Pb²⁺. Error bars correspond to standard deviation (n = 3).

Fig.3 Ratios of absorbance intensities (A₅₃₃/A₇₀₀) of the M5-DNAzyme–AuNP system at (a) different NaCl concentrations ranging from 50, 100, and 200 mmol/L with a fixed AuNP concentration of ~3.2 nmol/L; and (b) different substrate-to-enzyme molar ratios ranging from 1:1, 1:2, and 1:3.

Fig.4 (a) Visible spectra with various concentration of Pb²⁺. Inset of the color display from left to right represents Pb²⁺ at the concentrations of 0, 10, 20, 50, 80, 100, 200, 300, and 500 nmol/L, respectively; (b) absorption ratio of A₅₃₃/A₇₀₀ at different Pb²⁺ concentrations (linear fitting curve in the range of 10–300 nmol/L); (c) comparison of the LoD and detection time of this developed nanobiosensor with the state-of-the-art Pb²⁺ specific DNAzyme-based biosensors; (d) normalized colorimetric signals in the presence of 100 nmol/L individual metal ions. Error bars correspond to standard deviation (n = 3).

Tab.2 Analysis of Pb²⁺ concentrations in environmental water samples through spiked recovery and comparison of results with AAS detection

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