Nanotechnology Project

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Environment, Health and Safety Research

NIRT: Development, Functionalization, and Assembly of Nanoscale Biological Sensors

Project Information

Principal InvestigatorSeunghun Hong
InstitutionFlorida State University
Project URLView
Relevance to ImplicationsMarginal
Class of NanomaterialEngineered Nanomaterials
Impact SectorCross-cutting
Broad Research Categories Hazard
NNI identifier

Funding Information

Anticipated Total Funding$1,050,000.00
Annual Funding$210,000.00
Funding SourceNSF
Funding MechanismExtramural
Funding SectorGovernment
Start Year2002
Anticipated End Year2007


This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NIRT. We propose a project to develop nanoscale biological sensors with single molecule detection capability and, more importantly, a novel technique for nanoscale functionalization and assembly of these sensors. The devices will consist of several nanoscale building blocks: 1) ultra-sensitive semiconductor Hall gradiometer capable of detecting a single 5-nm diameter magnetic nanoparticle (magnetic detection); 2) nanoscale field effect transistor (FET) based on newly developed semiconducting metal oxide nanobelts (electrical detection). We will employ dip-pen nanolithography (DPN) to functionalize individual solid state devices to detect specific biological substances. Furthermore, DPN-decorated solid substrates will be utilized to assemble nanoscale building blocks onto specific patterns from solution.

The practicality of any biological sensor is governed by its: 1) selectivity, 2) sensitivity, and 3) environmental compatibility. We have recently demonstrated that sub-micrometer Hall gradiometers, made out of GaAs/AlGaAs two-dimensional electron gas, can detect a single 10-nm-diameter magnetic particle. They are ideally suited for detecting the presence of adsorbed biomolecules tagged with magnetic nanoparticles. We will fabricate gradiometers out of InAs heterostructures for the optimal performance under ambient conditions. For electrical detection of biological molecules, we intend to fabricate nanoscale FET’s from a group of metal oxide nanobelts. In this case, charged molecules adsorbed on the functionalized nanobelt surfaces can be detected by measuring the conductivity change of the nanobelt junctions.

Utilizing DPN, the nanoscale Hall gradiometer surface and nanobelt FET channel can be functionalized to create specific affinity for desired biomolecules, which allows us to build highly selective sensing devices. Furthermore, multiple nano-FET’s can be assembled onto specific locations on a substrate or in a circuit via surface-templated nano-assembly strategy. In this method, the solid substrate will be first functionalized with chemical binding groups with specific affinity to the nanobelts, and then the substrates will be used to capture the nanobelts from their solution.

Successful execution of the proposed program will not only produce several highly sensitive novel biosensors with immediate application values, but also create a new paradigm for biosensor fabrication and assembly that may be widely applicable in many other systems. To accomplish the stated goals, we have assembled a team of six researchers in biology, physics, materials science, and electrical engineering from three institutions. This team provides a unique interdisciplinary combination and possesses all the necessary expertise and tools for the project. In addition, this interdisciplinary research project will provide many students a valuable opportunity to collaborate with researchers in other disciplines.