Moving to mercury: The first triboelectric effect‐based sensor for the detection of Hg2+ ions by using Au nanoparticles (see picture; red) as electrical performance enhancer and recognition element ...has been successfully demonstrated. This self‐powered and stand‐alone triboelectric nanosensor has the advantages of simplicity, low cost, high selectivity, and sensitivity.
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•Insights provided on a diverse range of multi-dimensional nanoparticles as biosensors.•Details on structure and application of 0, 1, 2 and 3D composited nanosensors.•Electrochemical ...performance analyzed on uric acid, ascorbic acid and dopamine.•Data provided is helpful to choose a appropriate biosensor with high accuracy and selectivity.•Covers recent advances on eco-friendly sensors/techniques of synthesis.
A well framed electrochemical platform is necessary to detect efficiently molecules of clinical importance. Among several, uric acid, ascorbic acid and dopamine being found in the human body (metabolic pathway, blood and urine) can be correlated to many diseases like schizophrenia, Parkinson, hyperuricemia, etc. Conventional electrochemical techniques have associated bottlenecks related to sensitivity, selectivity, overlapping oxidation potential, interfering molecules, electrode fouling leading to false positive or negative results. Recent advances suggest the role of nanoparticles having various dimensions as ‘electrode modifiers’ to overcome these bottlenecks. The multidimensional nanoparticles could be categorized as zero, one, two and three-dimensional based on their structural conformation. Depending on the environment and interfering molecules surrounding an analyte, the choice of nanoparticles is extremely promising and could be Q-Dot, nanotubes, nanowires, nanosheets, nanochannels, nanocages and nanoflowers. Choosing the right nanoparticle could enhance the electrocatalytic activity due to high surface area, reduce interference by separating oxidation peaks and bear structural stability as well as biocompatibility for in-vivo applications. Current review additionally highlights enhancement of electrocatalytic activities using aptamers (in aptasensors) for signal amplification or ‘greener materials’ (clay, biowaste, eco-friendly solvents) for developing porous electrodes and synthesizing sensors with an eco-friendly approach.
To maintain a green and sustainable environment for human beings, rapid detection of potentially toxic heavy metals like mercury (Hg(II)) has attracted great attention. Recently, sensors have been ...designed which can selectively detect Hg(II) over other common available cations and give a naked eye or fluorometric response. In the last two decades, the trend is shifting from bulky organic chemosensors toward nanoparticles due to their rapid response, low cost, eco-friendly and easy synthesis. In this review, promising nanoparticles-based sensors for Hg(II) detection are discussed. The nano-sensors are functionalized with nucleotide or other suitable materials which coordinate with Hg(II) ions and give clear color or fluorescence change. The operational mechanisms are discussed focusing on its four basic types. The nanoparticles-based sensors are even able to detect Hg in three different oxidation states (Hg(II), Hg(I) and Hg(0)). Recently, the trend has been shifted from ordinary nanoparticles to magnetic nanoparticles to simultaneously detect and remove Hg(II) ions from environmental samples. Furthermore, the nano-sensors for Hg(II) are compared with each other and with the reported organic chemosensors.
A ratiometric fluorescent nanosensor has been developed for probing Ag+ ions based on the fluorescence resonance energy transfer (FRET) between graphene quantum dots (GQDs) and 2,3-diaminiophenazine ...(DAP) yielded from the Ag+ ions-oxidized o-phenlyenediamine (OPD).
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•A novel ratiometric fluorescent nanosensor for Ag+ ions was established with GQDs.•The oxidase-like activity of Ag+ ions towards OPD was employed for the design of this nanosensor.•A FRET mechanism between GQDs and DAP was demonstrated.•This rationmetric fluorescent nanosensor can detect Ag+ ions in water samples.
A ratiometric fluorescent nanosensor was reported for the first time for the sensitive and selective analysis of Ag+ ions by employing graphene quantum dots (GQDs) as the reference fluorophore and o-phenylenediamine (OPD) as the specific recognition probe. Upon the addition of Ag+ ions, OPD could be oxidized to produce 2,3-diaminophenazine (DAP) with a strong fluorescence emission at 557nm, whereas the fluorescence of GQDs at 445nm would be simultaneously quenched by the so generated DAP through fluorescence resonance energy transfer (FRET). A ratiometric fluorescent Ag+ nanosensor was thus developed. The fluorescence intensity ratios of DAP to GQDs linearly increased with the increasing of Ag+ concentrations in the range of 0–115.2μM, with a detection limit down to 250nM. Furthermore, the feasibility of practical applications of the developed detection strategy for probing Ag+ ions in real water samples was demonstrated.
Precision medicine applications supported by nanotechnologies enforce designing a communication interface between in-body nanosensors and external gateways. Such a communication interface will enable ...both a data and a control channel between nanodevices operating within the human body and external control units. In this direction, recent literature focuses on deriving analytic channel models for intra-body links through the human tissues, including the analysis of achievable communication capacities in the terahertz band. A yet missing component, however, is a synchronization module to implement communication schemes in the intra-body link. Such synchronization module will ultimately bound the communication performance regarding the perceived signal to noise ratio (SNR) and bit error rate (BER), for instance. This paper contributes to the state of the art in two directions: (a) evaluating the bounds on the communication performance with the Cramer-Rao lower bound (CRLB) for the synchronization symbol timing offset (STO) and (b) designing a low-complex mechanism to synchronize communication. This analysis considers a communication link between external gateways located on the skin and nanosensor devices flowing in the human vessels. Using envelope and slope detectors, we devise a low-complex solution that relies on the received signal strength (RSS) metric to trigger data emissions. The method estimates the peak of the received RSS metric to ignite communication in the most favorable location, i.e., when the nanosensor is located at the shortest distance in the communication range with external gateways. Our findings illustrate the feasibility of such a low-complex synchronization method. Performance illustrates a BER less than 1×10 −5 for those nanosensors traveling close to the upper vessel wall.
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•The novel hybrid material (FT@CNT) was prepared by surface modification of the carbon nanotube with thiophene-ferrocene moieties.•The novel FT@CNT hybrid material were fully ...characterized by spectroscopic, microscopic and thermal techniques.•The experimental conditions were fully optimized for determination of parathion and chlorantraniliprole pesticides in real samples.•Accuracy of the electrochemical methods was evaluated by spike/recovery and HPLC analysis in food and soil samples.
The overuse of pesticides for agricultural activities causes adverse effects on human health and can lead to ecological pollution. Therefore, there has been a growing demand for accurate, sensitive, simple, and selective analytical methods for the determination of pesticide residues in food products, soil, etc. In this study, an electrochemical method was developed for the simultaneous determination of parathion and chlorantraniliprole pesticides based on novel electroactive and electropolymerizable group bearing hybrid nanomaterial. The novel hybrid ferrocene-thiophene modified by carbon nanotube (FT@CNT) was prepared by surface modification of the carbon nanotube with thiophene-ferrocene moieties via Click chemistry and used as an electrochemical nanosensor. The experimental conditions such as pH and concentration of the nanosensor were optimized prior to the electrochemical determination of parathion and chlorantraniliprole pesticides in tomatoes, apples and soil samples. The LODs for parathion and chlorantraniliprole in the linear range of 0.02−6.50 μmol/L and 0.01−7.00 μmol/L were determined as 5.3 nmol/L and 8.1 nmol/L, respectively. The accuracy of the electrochemical methods was evaluated by spike/recovery and HPLC analysis in food and soil samples. The comparison between the electrochemical method and other analytical techniques for the determination of pesticides revealed that the electrochemical methods were not only easy to operate and fast but also highly sensitive and selective for the simultaneous determination of parathion and chlorantraniliprole residues in food and soil samples. The hybrid material demonstrated excellent stability and high sensitivity towards parathion and chlorantraniliprole pesticides.
An ultraflexible and stretchable field‐effect transistor nanosensor is presented that uses aptamer‐functionalized monolayer graphene as the conducting channel. Specific binding of the aptamer with ...the target biomarker induces a change in the carrier concentration of the graphene, which is measured to determine the biomarker concentration. Based on a Mylar substrate that is only 2.5‐µm thick, the nanosensor is capable of conforming to underlying surfaces (e.g., those of human tissue or skin) that undergo large bending, twisting, and stretching deformations. In experimental testing, the device is rolled on cylindrical surfaces with radii down to 40 µm, twisted by angles ranging from −180° to 180°, or stretched by extensions up to 125%. With these large deformations applied either cyclically or non‐recurrently, the device is shown to incur no visible mechanical damage, maintain consistent electrical properties, and allow detection of TNF‐α, an inflammatory cytokine biomarker, with consistently high selectivity and low limit of detection (down to 5 × 10−12 m). The nanosensor can thus potentially enable consistent and reliable detection of liquid‐borne biomarkers on human skin or tissue surfaces that undergo large mechanical deformations.
An ultraflexible and stretchable affinity nanosensor consisting of aptamer‐functionalized graphene on a 2.5‐µm Mylar substrate is presented. Aptamer‐biomarker binding induces a measurable change in the carrier concentration of the graphene for determination of the biomarker concentration. The device is shown to incur no visible mechanical damage, and maintain consistent electrical properties and biomarker responses under large bending, twisting, and stretching deformations.
A recyclable and green triboelectronic nanogenerator (TENG) is developed based on triboelectrification and designed cascade reactions. Once triggered by water, the TENG can fully dissolve and degrade ...into environmentally benign end products. With features of rapid dissolution, reproductivity, and green electronic, the TENG has potential of serving as clearable energy harvester and nanosensor for health monitoring and motion sensing.
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