Electric Field-Induced Specific Preconcentration to Enhance DNA-Based Electrochemical Sensing of Hg²⁺ via the Synergy of Enrichment and Self-Cleaning

Abstract

Efficient preconcentration is critical for sensitive and selective electrochemical detection of metal ions, but rapid specific enrichment with depressed absorption of interfering ions at the electrode is challenging. Here, we proposed an electric fieldinduced specific preconcentration to boost the analytical performance of DNA-based electrochemical sensors for Hg 2+ detection. As for such preconcentration, a positive external electric field was first used to enrich Hg 2+ at an electrode assembled with T-rich DNA, thus boosting T−Hg 2+ −T recognitions. The following applied inverse electric field strips the nonspecifically absorbed Hg 2+ and other interfering ions, thus depressing matrix interferences via self-cleaning. Based on this principle, we designed a portable device to realize programmable control of electric fields; a T−Hg 2+ −T recognition-based electrochemical sensor was thus fabricated as a model platform to assess the feasibility of electric field-induced preconcentration. The experimental results revealed that such a strategy decreased the time of T−Hg 2+ −T-based recognition from 60 to 20 min and led to detection with better reproducibility by depressing the influence of free Hg 2+ as well as interfering ions. This strategy offered Hg 2+ detection limits of 0.01 pMthree-fold better than that without preconcentrationwithin 22 min. The proposed preconcentration strategy offers a new way to enhance the analytical performance of sensing at the solid−liquid interface.

Isolation of Sensing Units and Adsorption Groups Based on MOF-on-MOF Hierarchical Structure for Both Highly Sensitive Detection and Removal of Hg2+

“…The mercury ion (Hg 2+ ) is one of the most hazardous and widespread pollutants in water-based ecosystems. − Due to its high migration and nonbiodegradability, the World Health Organization (WHO) specifies the safety thresholds for Hg 2+ as 5 and 1 ppb in discharged wastewater and drinking water, respectively, highlighting that the sensitive detection and efficient removal of Hg 2+ are imperative. − Currently, a variety of state-of-the-art methods, including fluorescence (FL), electrochemistry, and colorimetry, are being developed for detecting Hg 2+ . − In particular, FL offers simple operation, rapid response, and high sensitivity . In parallel, compared with ion exchange, membrane filtration, and chemical precipitation, adsorption is regarded as a promising removal method owing to its ease of implementation and cost-effectiveness. − However, traditional FL probes and adsorbents offer only a single sensing or adsorption function.…”

Unique three-dimensional ordered macroporous dealloyed gold–silver electrochemical sensing platforms for ultrasensitive mercury(ii) monitoring

“…In turn, the increase or decrease in the electrochemical response of the redox label is usually proportional to the Hg 2+ concentration. [39][40][41] Based on the above-mentioned research, a unique and ultrasensitive electrochemical sensor was constructed for the detection of Hg 2+ based on a 3D ordered macroporous dealloyed (3DOMD) Au-Ag thin film sensing platform and thionine (Thi)-capped porous hollow Au@platinum (Pt) nanocages probe DNA ( pDNA) conjugates (Thi-APNC-pDNA). Two compelling steps were taken in this work: (1) 3DOMD Au-Ag thin films were prepared by the dealloying method and used as a platform for immobilizing capture DNA (cDNA), which not only increases the sensing surface area, but also strengthens the electron transport capacity of the sensing base through its layered and porous framework; (2) APNCs were synthesized utilizing a plating substitution technique and used as an ideal substrate for loading a large number of pDNA and electroactive Thi molecules.…”

“…In turn, the increase or decrease in the electrochemical response of the redox label is usually proportional to the Hg 2+ concentration. 39–41…”

Molecularly Imprinted Electrochemical Sensor Based on the Self-Assembly of Cage-like Gold Nanoparticles and Amino-Functionalized rGO for the Detection of Diuron in Cotton Defoliant

“…Consequently, it is of great significance for environmental protection to quantify DU residue with high selectivity and sensitivity, but the correlation of detecting DU is still in its infancy. At present, the analytical methods of DU are mainly based on traditional chromatography; however, they are not suitable for the simple, rapid, and sensitive detection of DU because of their complex sample pretreatment, long analysis time, and expensive instruments. − In recent years, electrochemical sensing has attracted extensive attention thanks to its low cost, simple operation, and fast response. − …”