Selective detection of silver ions using mushroom-like polyaniline and gold nanoparticle nanocomposite-based electrochemical DNA sensor

A novel AuNP colorimetric sensor based on a polyadenine probe for ultra-sensitive detection of Ag. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023;15:626-630. [PMID: 36645653 DOI: 10.1039/d2ay02026b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Silver(I) ions (Ag⁺) are harmful to humans and can be bioaccumulated in organisms. Although numerous methods for Ag⁺ analysis have been established, new strategies are still in urgent need. Here, we propose a colorimetric sensor based on polyadenine (polyA)-mediated DNA-functionalized gold nanoparticles (AuNPs) for the specific measurement of Ag⁺ ions. In this strategy, a polyA-modified Au probe with high uniformity was assembled successfully. The method was based on Ag⁺-induced aggregation of the probe. Ag⁺ was reflected according to the color variations of solution. Taking advantage of the low cost and convenient assembly of the polyA-based Au probe, our strategy determined Ag⁺ with high sensitivity and wide range. In addition, by changing probes or nanoparticles, the proposed strategy is expected to be a universal platform for detecting other analytes in environmental and even biological samples.

Portable quantification of silver ion by using personal glucose meter (PGM) and magnetite cross-linked invertase aggregates (MCLIA)

Heavy metal detection is critical due to its harmful effects on human health and the ecosystem. Enzyme-based platforms attract attention for heavy metal detection such as silver, a toxic metal, due to being small, portable, and requiring only essential equipment compared with the basic analytical methods. In this study, magnetic cross-linked invertase aggregates (MCLIA) were developed for the first time as an enzyme-based signaling platform to detect Ag⁺ using a personal glucose meter (PGM). EDX, FTIR, and VSM results depicted that MCLIA was successfully developed and exhibits super-paramagnetism. In addition, MCLIA selectively detected the Ag⁺ at a sensitivity of 1.2 inhibition rate/μM in a linear range from 5 to 70 μM with a detection limit of 4.6 μM and IC₅₀ value of 42.3 μM. These findings strongly indicate that MCLIA is applicable as a signal platform for portable quantification of other analytes that inhibits the invertase enzyme.

Label-Free, Fast Response, and Simply Operated Silver Ion Detection with a Ti3C2Tx MXene Field-Effect Transistor

Silver (Ag) is a widely used heavy metal, and its oxidation state (Ag⁺) causes serious harm to organisms after bioaccumulation and biomagnification, posing urgent demand for the rapid, efficient, and simply operated Ag⁺ detection techniques. In this work, a fast, portable, and label-free Ag⁺ detection sensor based on a Ti₃C₂T_x MXene field-effect transistor (FET) is reported. The Ti₃C₂T_x MXene works as the sensing element in the FET sensor, which shows excellent sensing performance, i.e., fast response (few seconds) and good sensitivity and selectivity to Ag⁺ without any detection label or probe. Utilizing the visual photograph, transmission electron microscopy image, and Ag elemental mapping analysis, the sensing mechanism of the label-free Ti₃C₂T_x MXene FET sensor is demonstrated to be the in situ reduction of Ag⁺ and the formation of Ag nanoparticles (AgNPs). Moreover, Ag⁺ detection in real samples shows that the proposed FET devices have satisfactory sensing capability for Ag⁺ in tap water and river water. This study puts forward a novel FET strategy for Ag⁺ detection in aqueous systems, which is of essential and inspiring meaning for motivating the potential applications of MXene-based sensor devices in analytical applications and the realization of on-site environmental monitoring.

Application of DNA-Nanosensor for Environmental Monitoring: Recent Advances and Perspectives

PURPOSE OF REVIEW

Environmental pollutants are threat to human beings. Pollutants can lead to human health and environment hazards. The purpose of this review is to summarize the work done on detection of environmental pollutants using DNA nanosensors and challenges in the areas that can be focused for safe environment.

RECENT FINDINGS

Most of the DNA-based nanosensors designed so far use DNA as recognition element. ssDNA, dsDNA, complementary mismatched DNA, aptamers, and G-quadruplex DNA are commonly used as probes in nanosensors. More and more DNA sequences are being designed that can specifically detect various pollutants even simultaneously in complex milk, wastewater, soil, blood, tap water, river, and pond water samples. The feasibility of direct detection, ease of designing, and analysis makes DNA nanosensors fit for future point-of-care applications.

SUMMARY

DNA nanosensors are easy to design and have good sensitivity. DNA component and nanomaterials can be designed in a controlled manner to detect various environmental pollutants. This review identifies the recent advances in DNA nanosensor designing and opportunities available to design nanosensors for unexplored pathogens, antibiotics, pesticides, GMO, heavy metals, and other toxic pollutant.

In situ synthesis of hierarchical platinum nanosheets-polyaniline array on carbon cloth for electrochemical detection of ammonia

In this work, a self-supported electrode has been designed and fabricated based on carbon cloth-supported polyaniline array and Pt nanosheets (Pt-PANI-CC). PANI array was firstly loaded on the surface of CC via chronoamperometry technique, and then, Pt nanosheets were deposited on the per-grown PANI array through amperometric measurement. The hierarchical structure of Pt-PANI-CC electrode and unique sheet-like Pt nanoparticles offered large specific surface and response centers. The electrochemical sensor based on Pt-PANI-CC electrode has been successfully constructed for detection of ammonia. The experiment results demonstrated that Pt-PANI-CC displayed great catalytic activity for electro-oxidation of ammonia and exhibited acceptable performances for sensing ammonia with low detection limit of 77.2 nM and wide linear range from 0.5 μM to 550 μM. Moreover, the anti-interference ability, reusability, reproducibility and stability of sensor have been investigated and showed great performances. This work provides a promising way for designing self-supported sensing electrode toward a wide electrochemical detection.

Recent uses of carbon nanotubes & gold nanoparticles in electrochemistry with application in biosensing: A review

The innovation of nanoparticles assumes a critical part of encouraging and giving open doors and conceivable outcomes to the headway of new era devices utilized as a part of biosensing. The focused on the quick and legitimate detecting of specific biomolecules using functionalized gold nanoparticles (Au NPs), and carbon nanotubes (CNTs) has turned into a noteworthy research enthusiasm for the most recent decade. Sensors created with gold nanoparticles or carbon nanotubes or in some cases by utilizing both are relied upon to change the very establishments of detecting and distinguishing various analytes. In this review, we will examine the current utilization of functionalized AuNPs and CNTs with other synthetic mixes for the creation of biosensor prompting to the location of particular analytes with low discovery cutoff and quick reaction.

DNA-functionalized gold nanoparticle-based fluorescence polarization for the sensitive detection of silver ions

Despite their practical applications, Ag⁺ ions are environmental pollutants and affect human health. So the effective detection methods of Ag⁺ ions are imperative. Herein, we developed a simple, sensitive, selective, and cost-effective fluorescence polarization sensor for Ag⁺ detection in aqueous solution using thiol-DNA-functionalized gold nanoparticles (AuNPs). In this sensing strategy, Ag⁺ ions can specifically interact with a cytosine-cytosine (CC) mismatch in DNA duplexes and form stable metal-mediated cytosine-Ag⁺-cytosine (C-Ag⁺-C) base pairs. The formation of the C-Ag⁺-C complex results in evident changes in the molecular volume and fluorescence polarization signal. To achieve our aims, we prepared two complementary DNA strands containing C-base mismatches (probe A: 5'-SH-A₁₀-TACCACTCCTCAC-3' and probe B: 5'-TCCTCACCAGTCCTA-FAM-3'). The stable hybridization between probe A and probe B occurs with the formation of the C-Ag⁺-C complex in the presence of Ag⁺ ions, leading to obvious fluorescence quenching in comparison to the system without AuNP enhancement. The assay can be used to identify nanomolar levels of Ag⁺ within 6 min at room temperature, and has extremely high specificity for Ag⁺, even in the presence of higher concentrations of interfering metal ions. Furthermore, the sensor was successfully applied to the detection of Ag⁺ ions in environmental water samples and showed excellent selectivity and high sensitivity, implying its promising application in the future.

A simple and sensitive sensor for silver ions based on unmodified gold nanoparticles by using dynamic light scattering techniques

A simple and sensitive assay for Ag+ was developed with unmodified gold nanoparticles (AuNPs) by using dynamic light scattering techniques. Ag+ could induce the oligonucleotide (5′-ATC ACT ATA TCA TAT ACT CAT-3′) to change from a single-stranded structure to a double-stranded structure and desorb from the surface of AuNPs, which triggered the aggregation of AuNPs in the salt solution. The average hydrodynamic diameter of aggregated AuNPs could be detected by using dynamic light scattering techniques. Under the optimum conditions, the average hydrodynamic diameter of AuNPs is proportional to the concentration of Ag+ within the range of 13.3–100.0 nmol/L, with a detection limit of 3.2 nmol/L. The method is easy to operate and has low sample consumption, high sensitivity and selectivity.