Nanoparticles enzyme, construction

Particularly attractive for numerous bioanalytical applications are colloidal metal (e.g., gold) and semiconductor quantum dot nanoparticles. The conductivity and catalytic properties of such systems have been employed for developing electrochemical gas sensors, electrochemical sensors based on molecular- or polymer-functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme-based electrodes, immunosensors, and DNA sensors. Advances in the application of molecular and biomolecular functionalized metal, semiconductor, and magnetic particles for electroanalytical and bio-electroanalytical applications have been reviewed by Katz et al. [142]. 

Metallic nanoparticles and single-walled carbon nanotubes (SWCNTs) exhibit nanoscale dimensions comparable with the dimensions of redox proteins. This enables the construction of NP-enzyme or SWCNT-enzyme hybrids that combine the unique conductivity features of the nanoelements with the biocatalytic redox properties of the enzymes, to yield wired bioelectrocatalyts with large electrode surface areas. Indeed, substantial advances in nanobiotechnology were achieved by the integration of redox enzymes with nanoelements and the use of the hybrid systems in different bioelectronic devices.35... 

Nanoparticles are well suited for construction of third generation enzyme biosensors that rely on the direct electron transfer between redox centers buried within the protein and electrodes. The small size of the particles provides ideal environments for contacting redox centers with little loss of bioactivity, while the conductive nature of the metal particles facilitates communication with the underlying electrode by providing a means of electron shuttling. 

This chapter has addressed recent advances in the application biomolcules immobilized onto metal oxide nanoparticles for fabrication of biosensors. Electrochemical contacting of redox enzymes or proteins with electrode surfaces is a key step in construction of third generation reagent-free biosensors. We have described a variety of metal oxide nanoparticles... 

Mena, M.L.,Yanez-Sedeno, P., Pingarron, J.M. (2005) A comparison of different strategies for the construction of amperometric enzyme biosensors using gold nanoparticle-modified electrodes. Anal. Biochem., 336, 20-27... 

Nishiyabu et al." describe nanoparticles based on supramolecular networks of nucleotides and lanthanides. Multimodahty is achieved in this system by enclosing entities such as dyes, enzymes, and gold nanoparticles. Gold nanoparticles were formed capped with 5 -GMP, and then mixed in buffer with GdCla to generate a supramolecular network on the particle surface. The nucleotide/lanthanide nanoparticles were reported to have longitudinal relaxivities (ri) of 12.5 s mM. Much remains to be determined about the utility of these constructs for clinical applications. 

---