https://zenodo.org/record/1258475/files/article.pdf

Electron transfers in chemistry and biology

Detection of chemical and biological agents plays a fundamental role in biomedical, forensic and environmental sciences1–4 as well as in anti bioterrorism applications.5–7 The development of highly sensitive, cost effective, miniature sensors is therefore in high demand which requires advanced technology coupled with fundamental knowledge in chemistry, biology and material sciences.8–13

In general, sensors feature two functional components: a recognition element to provide selective/specific binding with the target analytes and a transducer component for signaling the binding event. An efficient sensor relies heavily on these two essential components for the recognition process in terms of response time, signal to noise (S/N) ratio, selectivity and limits of detection (LOD).14,15 Therefore, designing sensors with higher efficacy depends on the development of novel materials to improve both the recognition and transduction processes. Nanomaterials feature unique physicochemical properties that can be of great utility in creating new recognition and transduction processes for chemical and biological sensors15–27 as well as improving the S/N ratio by miniaturization of the sensor elements.28

Gold nanoparticles (AuNPs) possess distinct physical and chemical attributes that make them excellent scaffolds for the fabrication of novel chemical and biological sensors (Figure 1).29–36 First, AuNPs can be synthesized in a straightforward manner and can be made highly stable. Second, they possess unique optoelectronic properties. Third, they provide high surface-to-volume ratio with excellent biocompatibility using appropriate ligands.30 Fourth, these properties of AuNPs can be readily tuned varying their size, shape and the surrounding chemical environment. For example, the binding event between recognition element and the analyte can alter physicochemical properties of transducer AuNPs, such as plasmon resonance absorption, conductivity, redox behavior, etc. that in turn can generate a detectable response signal. Finally, AuNPs offer a suitable platform for multi-functionalization with a wide range of organic or biological ligands for the selective binding and detection of small molecules and biological targets.30–32,36 Each of these attributes of AuNPs has allowed researchers to develop novel sensing strategies with improved sensitivity, stability and selectivity. In the last decade of research, the advent of AuNP as a sensory element provided us a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.37



Figure 1

Physical properties of AuNPs and schematic illustration of an AuNP-based detection system.



In this current review, we have highlighted the several synthetic routes and properties of AuNPs that make them excellent probes for different sensing strategies. Furthermore, we will discuss various sensing strategies and major advances in the last two decades of research utilizing AuNPs in the detection of variety of target analytes including metal ions, organic molecules, proteins, nucleic acids, and microorganisms.

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Gold nanoparticles in chemical and biological sensing.

The science of the total environment

Recent developments in polysaccharide-based materials used as adsorbents in wastewater treatment

Direct And Mediated Anodic Oxidation of Organic Pollutants

This paper reports the distribution of a series of metals in natural samples collected at Carezza Lake in Antarctica, during the Italian Expedition in the austral summer 1989/90. The considered elements are: water, sediments and soil sampled from the surroundings of the lake and algae. The determination of the total concentration of the following metals was performed: Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Zn. In addition, for sediment and soil samples, a speciation study was performed for some metals, namely Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, using the Tessier procedure.

Distribution of Minor and Trace Metals in Carezza Lake (ANTARCTICA) Ecosystem

Evaluation of the intrinsic parameters of octacyano-molybdate(IV) and -(V) and hexacyanoferrate(II) and -(III) from a kinetic study of the oxidation of benzenediols

An ion-chromatographic procedure is described for the determination of selenium (VI) at μg L−1 level in the presence of anions and heavy metal ions. Maximum permissible concentrations and effects from each interfering substance were investigated for the Se concentration range 12.5–1,000 μg L−1. The method, optimized for the detection of SeO42−, gives results suitable for speciation analysis. Total selenium can be determined after complete conversion to selenate ion by oxidation with KMnO4. The detection limit of selenium is 4.8 μg L−1 (0.96 ng for 200 μL sample).

Simultaneous ion chromatographic determination of selenium and metal ions in waters at trace level

Use of methyliminodiacetic acid bound to cellulose for preconcentration and determination of trace-metal cations

The kinetics and mechanism of oxidation of 1,4-dihydroxybenzene (H2Q), 2,5-dihydroxybenzenesulphonic acid (H2SQ) and 4,5-dihydroxy-1,3-benzenedisulphonic acid (H2T) to the correspondingortho orPara-quinones by ethylenediaminetetraacetatomanganate (III) has been investigated over the 2.5–6.0 pH range, at 20.0° by the stopped-flow technique. Complex behaviour is observed for H2Q due to the superposition of the precursor complex formation and the redox act, while at higher pH's these reactions separate. For the other substrates, a single second order step (first order in each reactant) was present whose rate showed different pH dependences. All these features are discussed with reference to the reduction potential of the substrates, their acidity and coordinating ability.

Edoardo Mentasti

Papers

Distribution of Minor and Trace Metals in Carezza Lake (ANTARCTICA) Ecosystem

Evaluation of the intrinsic parameters of octacyano-molybdate(IV) and -(V) and hexacyanoferrate(II) and -(III) from a kinetic study of the oxidation of benzenediols

Simultaneous ion chromatographic determination of selenium and metal ions in waters at trace level

Use of methyliminodiacetic acid bound to cellulose for preconcentration and determination of trace-metal cations

The Kinetics and mechanisms of oxidation of dihydroxybenzenes by ethylenediaminetetraacetatomanganate(III)