DNA‐Templated Assembly of a Protein‐Functionalized Nanogap Electrode

Abstract

The demand for integrated circuits that will allow information to be processed at even faster speeds remains undiminished. This is despite the fact that, as a result of miniaturization, the density of the wires and switches that comprise such circuits has doubled every eighteen months, giving rise to Moore's Law. [1] While it is expected that Moore's Law will hold true until 2016, it is not expected that it will hold true thereafter for two reasons. [2] The first reason is that to build smaller wires and switches requires major advances in the established fabrication and materials technologies. Specifically, it requires the development at great cost of new light sources and process tools; new mask and resist materials; and new high-and low-dielectricconstant materials. The second reason is that as wires and switches become smaller, the materials of which they are composed no longer exhibit bulk properties, but exhibit properties dominated by confinement and surface effects.The responses of the related scientific and engineering communities have been two-fold. The first response has been to develop alternative fabrication technologies. The second response has been to propose new integrated circuit architectures that can accommodate or even exploit the novel properties exhibited by these smaller wires and switches.When contemplating alternative fabrication technologies, one is immediately attracted to the self-assembly in solution and self-organization at a conventionally patterned silicon wafer substrate of nanoscale wires and switches. [3] When contemplating alternative materials technologies, one is immediately attracted to the use of biological molecules as templates and modified nanoparticles as building blocks. [4,5] It is noted that there have been a number of recent reports that have demonstrated the potential of these and related approaches. [6±10] It is in this context that we report the deoxyribonucleic acid (DNA) templated assembly of a protein-functionalized 10 nm gap electrode from suitably modified gold nanoparticles on a silicon wafer substrate. We also report that the above proteinfunctionalized electrode is recognized and bound selectively by a suitably modified gold nanoparticle and is localized in the 10 nm gap.Our five-step strategy is illustrated in Figure 1. The first step is to assemble a thiol-DNA-biotin template in solution and to deposit it on a silicon wafer substrate. It is expected that in the future these thiol groups will locate the template in the gap between the conventionally patterned gold electrodes. The second step is to expose the substrate to a dispersion of suitably modified gold nanoparticles. These nanoparticles selectively bind the DNA backbone of the template, leading to its partial metallization. The third step is to expose the substrate to a dispersion of the protein streptavidin. This protein recognizes and selectively binds the biotin located at the midpoint of the template. Furthermore, this protein displaces any partially bound gold nanoparticles in the vicinity ...

Nanogap Electrodes

“…The gaps between the metal leads can be easily scaled down to submicrometer level, depending on the width of the organic ribbons. More innovatively, Ongaro et al [135] presented a thiol-DNA-biotin template method to assemble a proteinfunctionalized 10 nm gap gold electrode onto a silicon wafer substrate. Modified gold nanoparticles were selectively adsorbed onto the DNA backbone to form the electrode.…”

A Flexible Method for the Fabrication of Gold Nanostructures Using Oligonucleotide Derivatives

“…Using these oligonucleotides the DNA-templated assembly of a protein-functionalized 10 nm gap electrode, from suitably modified gold nanoparticles on a silicon wafer substrate, was achieved (6)(7)(8). This protein-functionalized electrode was recognized and selectively bound by a suitably modified gold nanoparticle that was localized in the 10 nm gap (6)(7)(8).…”

“…We are interested in the preparation of synthetic DNA derivatives designed to assemble a molecular wire between two or three gold electrodes, which are needed to address individual nanoparticles from macroscopic electrodes (5)(6)(7)(8). Synthetic oligonucleotides were used to prepare the molecular wires, offering the possibility to introduce modifications at any predetermined position.…”

Synthesis of OligonucleotidePeptide Conjugates Carrying the c‐myc Peptide Epitope as Recognition System

“…Most of the experiments were performed using the recognition system of biotin and streptavidin because of the high affinity of the biotin-streptavidin interaction [17]. Recently, we described the use of branched oligonucleotides carrying biotin to direct one single nanoparticle to the middle of a lineal DNA duplex using the biotin-streptavidin system [18][19][20].…”

“…Our aim is the preparation of oligonucleotide-peptide conjugates (scheme 1) consisting of two sequences connected by a non-DNA material such as hexaethyleneglycol (=3,6,9,12,15-pentaoxaheptadecane-1,17-diol) ((EG) 6 ). This type of oligonucleotide may be used to assemble nanomaterials as described previously [18] [20]. Moreover, the presence of the peptide in these oligonucleotides may direct nanoparticles to the middle of the structure using antibodies against the peptide.…”