Enric Casassas memorial lecture 2004 : Nanoparticle- and nanorod-biomaterial hybrid systems for sensor, circuitry and motor applications

Abstract

Biomolecule-nanoparticle (NP) hybrid systems provide functional assemblies for the construction of sensors, nanocircuitry and devices. The development of sensors based on functionalized NPs will be exemplified with the electrical contacting of glucose oxidase with Au NPs (1.4 nm) functionalized with the FAD cofactor, and with the optical detection of telomerase activity in cancer cells using CdSe-ZnS core-shell NPs. The use of DNAzymes for the amplified detection of DNA/telomerase activity is described. A hemin/G-quadruplex structure provides a biocatalytic label for the chemiluminescent or colorimetric detection of DNA/telomerase activity. The use of biomolecule-NP hybrid systems for nanocircuitry and devices is addressed by the polymerization of Au NPsfunctionalized G-actin followed by the catalytic enlargement of the filaments to generate continuous, conductive Aunanowires. Sequential polymerization of Au-NP-modified Gactin and G-actin yields patterned nanowires with motor functions. The immobilization of the filaments on a myosin interface results in the motility of the filaments upon addition of the ATP fuel. The nano-objects move on the surface at a speed corresponding to 250 nm.sec-1. A further facet of nanobiotechnology involves the coupling of biomolecules with nano/micro elements to functional hybrid systems. This aspect is discussed by following the sequence-specific scission of a duplex DNA functionalized with magnetic particles on a cantilever by the endonuclease Mse I in the presence of an external magnetic field.