Electroanalytical and Bioelectroanalytical Systems Based on Metal and Semiconductor Nanoparticles

Abstract

Metal, semiconductor and magnetic particles act as functional units for electroanalytical applications. Metal nanoparticles provide three important functions for electroanalysis. These include the roughening of the conductive sensing interface, the catalytic properties of the nanoparticles permiting their enlargement with metals and the amplified electrochemical detection of the metal deposits and the conductivity properties of nanoparticles at nanoscale dimensions that allow the electrical contact of redox-centers in proteins with electrode surfaces. Also, metal and semiconductor nanoparticles provide versatile labels for amplified electroanalysis. Dissolution of the nanoparticle labels and the electrochemical collection of the dissolved ions on the electrode followed by the stripping-off of the deposited metals represents a general electroanalytical procedure. These unique functions of nanoparticles were employed for developing electrochemical gas sensors, electrochemical sensors based on molecular-or polymerfunctionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzymebased electrodes, immunosensors and DNA sensors. Semiconductor nanoparticles enable the photoelectrochemical detection of analytes. Several studies have revealed the photocurrent generation by enzyme-mediated processes and as a result of DNA hybridization. Magnetic particles act as functional components for the separation of biorecognition complexes and for the amplified electrochemical sensing of DNA or antigen/antibody complexes. Also, electrocatalytic and bioelectrocatalytic processes at electrode surfaces are switched by means of functionalized magnetic particles and in the presence of an external magnet.

Nanometal-Decorated Exfoliated Graphite Nanoplatelet Based Glucose Biosensors with High Sensitivity and Fast Response

“…20 In addition, metal nanoparticles could even provide electrochemical reversibility for redox reactions, which is not possible on the bulk metal electrode. 21 Hrapovic et al simply mixed a Pt nanoparticle suspension with single-walled carbon nanotubes (SWCNTs) Nafion suspension to create a glucose biosensor. 15 This study demonstrated that SWCNT provided an excellent support for the Pt nanoparticles for efficient electrical transfer; however, this method resulted in Pt nanoparticle agglomeration.…”

Influência do eletrólito na eletrodeposição de nanopartículas de Cu sobre eletrodo de diamante dopado com boro

“…Para avaliar a influência do processo de adsorção, foram usadas duas soluções de 10 -3 mol L -1 de CuSO 4 42 A corrente catódica inicial atribuída ao processo Ic foi associada à redução de íons Cu 2+ a íons Cu + de acordo com a reação 2:…”

“…1 Na área eletroquími-ca, particularmente, em eletroanálise, NPs têm sido amplamente utilizadas como nanomatérias funcionais de superfície. Dentre alguns artigos excelentes de revisão publicados na literatura, [2][3][4][5][6] Welch e Compton destacam quatro principais vantagens quanto ao uso de eletrodos modificados com NPs aplicadas em eletroanálise: elevada área superficial efetiva, aumento do transporte de massa, atividade catalítica e controle sobre o microambiente local. 2 Em uma visão mais detalhada, a deposição de NPs resulta em um aumento da rugosidade superficial, que contribui para o aumento da área condutora do eletrodo modificado.…”

Silver nanoparticle polymer composite based humidity sensor

“…Nanomaterials were found to have significant roles in a diverse range of analytical methods particularly in sensing applications [7][8][9][10][11] . The increased interest in nanomaterials, especially metallic nanostructures, may be attributed to the often novel physical and chemical properties these nanoparticles display when compared to their bulk counterparts [10,12] .…”