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

The agreement of the kinetic data concerning the oxidation of benzenediols by aquapentachloro-, diaquatetrachloro-, and hexabromo-iridate(IV) with a model proposed in the light of the Marcus theory, suggests that an outer-sphere electron transfer is the operative mechanism. The same reorganizational parameter λ(26 kcal mol–1) satisfies the reactions involving the chloro-complexes, whereas a lower value is valid for hexabromoiridate(IV)(21 kcal mol–1). An estimation of the intrinsic parameters for the self-exchange reactions involving these IrIV–IrIII pairs has been attempted.

Electron transfer between benzenediols and aquapentachloro-, diaquatetrachloro-, and hexabromo-iridate(IV)

Sulphonated azoligand for metal ion determination in ion interaction chromatography

Binding properties of aminopolycarboxylato ligands bound to cellulose.

Polystyrene and acrylic acid resins loaded with dibutyl-N,Ndiethyi-carbamyl phosphonate (DBDECP) and dihexyl-N,Ndiethyl-carbamylmethylene phosphonate (DHDECMP) were used for the liquid-solid extraction of Cm. The uptake of the metal ion was evaluated in batch and column experiments as a function of H N 0 3 or HCl concentrations. Quantitative recovery of 2 4 Cm was obtained from HNO3 for all resins loaded with DBDECP both in static and dynamic experiments. The results obtained with the different ligands, resins and experimental conditions are discussed.

Liquid-Solid Extraction of 244Cm with Ligand-Loaded Resins

The reactions of 4-(2-pyridylazo)resorcinol (H2 par) with Ga III and InIII have been studied in water and aqueous mixtures with methanol, acetonitrile, dimethyl sulphoxide, and NN-dimethylformamide at 25.0 °C and / 0.80 mol dm–3(NaClO4). The equilibrium constant, Kc, for M(Hpar)2+ formation (M = In or Ga) has been evaluated spectrophotometrically and its variation with the medium composition has been discussed with reference to different properties of the solvents. The kinetics of dissociation of M(Hpar)2+ by H+ have been investigated. The derived formation rate constants are discussed with reference to the mechanisms which operate for the different reacting metal species.

Kinetics and mechanisms of complex formation of gallium(III) and indium(III). The reactions with 4-(2-pyridyiazo)resorcinol in water and other mixed solvents

Edoardo Mentasti

Papers

Electron transfer between benzenediols and aquapentachloro-, diaquatetrachloro-, and hexabromo-iridate(IV)

Sulphonated azoligand for metal ion determination in ion interaction chromatography

Binding properties of aminopolycarboxylato ligands bound to cellulose.

Liquid-Solid Extraction of 244Cm with Ligand-Loaded Resins

Kinetics and mechanisms of complex formation of gallium(III) and indium(III). The reactions with 4-(2-pyridyiazo)resorcinol in water and other mixed solvents