Immobilization platinum nanoparticles

CNTs offer an exciting possibility for developing ultrasensitive electrochemical biosensors because of their unique electrical properties and biocompatible nanostructures. Luong et al. have fabricated a glucose biosensor based on the immobilization of GOx on CNTs solubilized in 3-aminopropyltriethoxysilane (APTES). The as-prepared CNT-based biosensor using a carbon fiber has achieved a picoamperometric response current with the response time of less than 5 s and a detection limit of 5-10 pM [109], When Nation is used to solubilize CNTs and combine with platinum nanoparticles, it displays strong interactions with Pt nanoparticles to form a network that connects Pt nanoparticles to the electrode surface. The Pt-CNT nanohybrid-based glucose biosensor... 

Mei Y, Sharma G, Lu Y, Drechsler M, Ballauff M, Irrgang T, Kempe R (2005) High catalytic activity of platinum nanoparticles immobilized on spherical polyelectrolyte brushes. Langmuir 21 12229-12234... 

Figure 8.2 Amplified detection of thrombin by a sandwich-like assay based on a platinum nanoparticle-labeled secondary aptamer. Thrombin is captured by an immobilized aptamer and then reacted with the nanoparticle-labeled secondary aptamer. The platinum nanoparticles are then used to perform the electrocatalytic reduction of added H2O2 detected by linear sweep voltammetry. [From Polsky et al. (2006).]...

Cattech highlights (1997) Zeolites and chirality, Cattech, 1,149-151. Mastalir, A., Szollosi, G., Kiraly, Z., Razga, Z. (2002) Preparation and characterization of platinum nanoparticles immobilized in dihydrocin-chonidine-modified montmorillonite and hectorite, /i/i/. Clay Sci. 22,9-16. Gross, L.H., Rys, P. (1974) Heterogeneous catalytic asymmetric hydrogenation, J. Org. Chem. 39, 2429-2430. 

FIGURE 3.8 Mapping of a 3D nanoparticle model onto a 2D surface model with active and inactive sites. The active site concept is the integral part of the heterogeneous surface model of nanoparticle activity, explored here for CO d electro-oxidation. Immobile adsorbs, preferentially, on specific sites called the active sites. The mobile CO d is found on the remaining inactive catalyst sites. (Reprinted with permission from Andreaus, B.et al. 2006. Kinetic modeling of COad monolayer oxidation on carbon-supported platinum nanoparticles. J. Phys. Chem. B, 110, 21028-21040, Figure 2,7,8,9, American Institute of Physics.)... 

Zou, Y. J., C. L. Xiang, L. X. Sun, and F. Xu, 2008. Glucose biosensor based on electrodeposition of platinum nanoparticles onto carbon nanotubes and immobilizing enzyme with chitosan-Si02 sol-gel. Biosens Bioelectronics 23 1010-16. 

An (-)-Ephedrine voltammetric sensor prepared through the immobilization of an MIP imprinted polymer for ephedrine in the range of 0.5-3 mM [426], and the MIP-coated gold electrode modified by chitosan-platinum nanoparticles (CS-PtNPs) and graphene-gold nanoparticles (GR-AuNPs) nanocomposites for the determination of erythromycin are other examples of the application of MIPs for the analysis of pharmaceutical species. The latter report used erythromycin as template and 2-mercapto-nicotinic acid functional monomers and yielded a linear response in the range of 7.0 x 10 -9.0 X 10 M and a detection limit of 2.3 x 10 M [378]. 

Immobilized catalysts for the aerobic oxidation of alcohols in aqueous media have also been developed [165]. An example is seen in the platinum nanoparticles dispersed in amphiphilic resin particles (ARPs). As shown in Table 6.6, a wide variety of alcohols, including not only benzyhc and aUyhc but also ahcyclic and... 

Nevertheless, classical heterogeneous catalysts like particulate noble metals may be immobilized on the nanotube surface as well. Nanoparticles of platinum or rhodium, for instance, can be deposited on cup-stacked carbon nanotubes by reductive precipitation (Figure 3.114b). The catalysts obtained this way suit an application in fuel cells run on methanol. Electrodes made from the nanotube material exhibit twice the efficiency as compared to the classical material XC-72-carbon. The particles of noble metal on the nanotube surface catalyze the direct conversion of methanol into CO2 (MeOH -1- H2O CO2 -1- 6 H -1- 6e ). A material to be employed in such fuel cells has to meet some essential requirements, including a maximal specific surface, a defined porosity and a high degree of crystalhnity. Carbon nanotubes are endowed with exactly these characteristics, which is why they are the most suitable material for electrodes. Their high price, however, is still prohibitive to an industrial scale application. 

Kang X et al (2007) A novel glucose biosensor based on immobilization of glucose oxidase in chitosan on a glassy carbon electrode modified with gold-platinum alloy nanoparticles/ multiwall carbon nanotubes. Anal Biochem 369(l) 71-79... 

FIGURE 9.3 a) UV-vis spectra of 2.5 0,M Pd3oG4NH2 solutions before (pH 3) and after (pH 8) reduction, b) Time-resolved UV-vis spectra of 2.5 pM PdjoGdNH solutions in the presence of 0.1 M KCl before (pH 3) and after (pH 8) reduction. Reprinted with permission from H. Ye, R.W.J. Scott, R.M. Crooks, Synthesis, Characterization, and Surface Immobilization of Platinum and Palladium Nanoparticles Encapsulated within Amine-Terminated Poly(amidomine) Dendrimers Langmuir 20 (2004) 2915. Copyright 2004 American Chemical Society. 

Ye HC, Scott RWJ, Crooks RM (2004) Synthesis, characterization, and surface immobilization of platinum and palladium nanoparticles encapsulated within amine-terminated poly(amidoamine) dendrimers. Langmuir 20 2915... 

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