Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultra-Sensitive Electrical Biosensor Unlocks Potential for Instant Diagnostic Devices

17.04.2012
Researchers at UC Santa Barbara propose Tunnel-FET based biosensor 10,000 times more sensitive than conventional FET-based sensors

A new quantum mechanical-based biosensor designed by a team at University of California, Santa Barbara offers tremendous potential for detecting biomolecules at ultra-low concentrations, from instant point-of-care disease diagnostics, to detection of trace substances for forensics and security.


Schematic of a Tunnel-FET biosensor proposed by UCSB researchers and its band diagram illustrating band-to-band-tunneling triggered by biomolecule conjugation. Credit: Peter Allen, UCSB

Kaustav Banerjee, director of the Nanoelectronics Research Lab and professor of Electrical and Computer Engineering at UCSB, and PhD student Deblina Sarkar have proposed a methodology for beating the fundamental limits of a conventional Field-Effect-Transistor (FET) by designing a Tunnel-FET (T-FET) sensor that is faster and four orders of magnitude more sensitive. The details of their study appeared in the April 2, 2012 issue of the journal Applied Physics Letters.

“This study establishes the foundation for a new generation of ultra-sensitive biosensors that expand opportunities for detection of biomolecules at extremely low concentrations,” said Samir Mitragotri, professor of Chemical Engineering and director of the Center for Bioengineering at UCSB. “Detection and diagnostics are a key area of bioengineering research at UCSB and this study represents an excellent example of UCSB's multi-faceted competencies in this exciting field.”

Biosensors based on conventional FETs have been gaining momentum as a viable technology for the medical, forensic, and security industries since they are cost-effective compared to optical detection procedures. Such biosensors allow for scalability and label-free detection of biomolecules – removing the step and expense of labeling target molecules with fluorescent dye.

The principle behind any FET-based biosensor is similar to the FETs used in digital circuit applications, except that the physical gate is removed and the work of the gate is carried out by charged versions of the biomolecules it intends to detect. For immobilizing these biomolecules, the dielectric surface enclosing the semiconductor is coated with specific receptors, which can bind to the target biomolecules – a process called conjugation.

“The thermionic emission current injection mechanism of conventional FET based biosensors puts fundamental limitations on their maximum sensitivity and minimum detection time,” said Banerjee, who conceived the idea in 2009 while studying the design of tunnel-FETs for ultra energy-efficient integrated electronics.

"We overcome these fundamental limitations by making Quantum Physics join hands with Biology" explained Sarkar, the lead author of the paper. "The key concept behind our device is a current injection mechanism that leverages biomolecule conjugation to bend the energy bands in the channel region, leading to the quantum-mechanical phenomenon of band-to-band tunneling. The result is an abrupt increase in current which is instrumental in increasing the sensitivity and reducing the response time of the proposed sensor.”

“The abruptness of current increase in an electrical switch is quantified by a parameter called subthreshold swing and the sensitivity of any FET based biosensor increases exponentially as the subthreshold swing decreases. Thus, similar devices such as Impact-ionization- or Nano-electromechanical-FETs are promising for biosensing applications,” explained Banerjee. “But since theT-FETs can be easily integrated in the widely available silicon-based semiconductor technology, they can be mass produced in a cost effective manner.”

According to the researchers, their T-FET biosensor is expected to have tremendous impact on research in genomics and proteomics, as well as pharmaceutical, clinical and forensic applications – including the growing market of in-vitro and in-vivo diagnostics. Banerjee and Sarkar have filed a patent disclosure for their technology, which the researchers anticipate can be ready for the marketplace in as few as two years.

The Nanoelectronics Research Lab (NRL) is affiliated with the UCSB College of Engineering. Professor Kaustav Banerjee is the director of the NRL and also affiliated with the California NanoSystems Institute and the Institute for Energy Efficiency at UCSB. Banerjee is a Fellow of IEEE and has been recently honored with the Humboldt Foundation’s Bessel Research Award. Deblina Sarkar is a PhD candidate in the Electrical and Computer Engineering department and one of three students worldwide to receive an IEEE Electron Devices Society PhD Fellowship in 2011.

Paper source: Applied Physics Letters

Media Contact
Melissa Van De Werfhorst
melissa@engineering.ucsb.edu

Melissa Van De Werfhorst | EurekAlert!
Further information:
http://www.ucsb.edu

More articles from Physics and Astronomy:

nachricht The broken mirror: Can parity violation in molecules finally be measured?
04.06.2020 | Johannes Gutenberg-Universität Mainz

nachricht K-State study reveals asymmetry in spin directions of galaxies
03.06.2020 | Kansas State University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Small Protein, Big Impact

In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.

Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...

Im Focus: K-State study reveals asymmetry in spin directions of galaxies

Research also suggests the early universe could have been spinning

An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...

Im Focus: New measurement exacerbates old problem

Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.

Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

Why developing nerve cells can take a wrong turn

04.06.2020 | Life Sciences

The broken mirror: Can parity violation in molecules finally be measured?

04.06.2020 | Physics and Astronomy

Innocent and highly oxidizing

04.06.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>