Ultra-sensitive electrical biosensor based on Tunnel-FET design beats conventional field effect transistors
April 17, 2012 // Julien Happich
Researchers at the University of California, Santa Barbara have come up with a new quantum mechanical-based biosensor that could detect biomolecules at ultra-low concentrations, from instant point-of-care disease diagnostics, to detection of trace substances for forensics and security.
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. 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."
A 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
"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 the T-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.
Visit the University of California - Santa Barbara
Br/N-based dopants open up the band-gap in graphene nanoplatelets for the design of FETs
December 20, 2013
Reaserchers at the Ulsan National Institute of Science and Technology (UNIST in Korea) unveiled a method for the mass production ...
IPC to hold conflict minerals workshops before May 31, 2014 reporting deadline
The 'Let there be light' applications of 2013
Solar inverter shipments to exceed 10-GW in Q4 2013 forecasts IHS
Acquisitions shake up telecoms chip landscape
December 19, 2013
Two major acquisitions are set to change the landscape of networking and telecom chip development.
Bosch sets up IoT subsidiary
Betting on GaN-on-GaN for efficient white light
IEC presses for a single charger specification for notebook computers
- UltraCMOS® Semiconductor Technology Platforms: A Rapid Advancement of Process & Manufacturing
- Managing Electrical Complexity with a Platform Level Approach and Systems Engineering
- 3mm × 3mm QFN IC Directly Monitors 0V to 80V Supplies
- Adaptive Cell Converter Topology Enables Constant Efficiency in PFC Applications
Interview"Future automotive applications need incredibly more computing power"
These days, the Autosar (Automotive Open System Architecture) development partnership celebrates its tenth anniversary. Launched with the goal to reduce the complexity of the heterogeneous software landscape ...
Filter WizardCheck out the Filter Wizard Series of articles by Filter Guru Kendall Castor-Perry which provide invaluable practical Analog Design guidelines.
Linear video channel
READER OFFERRead more
Internet of Things (IoT) manufacturer Ciseco has launched the Raspberry Pi ‘Wireless Inventors Kit’ (RasWIK), featuring 88 pieces to provide everything a Pi owner needs to follow a series of step-by-step projects or to create their own wireless devices, without the need for configuration or even writing code.
RasWIK has been designed to be highly accessible, demystifying the dark art of wireless and enabling anyone with basic computing skills to begin building wireless devices with a Raspberry Pi. You can create anything from a simple traffic light, to a battery monitor, or even a temperature gauge that sends data to the Xively IoT cloud so billions can access the data.This month, Ciseco is giving away twelve Raspberry Pi Wireless Inventors kits, worth £49.99 each for EETimes Europe's readers to win.
And the winners are...
In our previous reader offer, Farsens was giving away five kits for EEtimes Europe readers to evaluate its FenixVortex, Kineo and X1 wireless, battery free sensor tags.
Lucky winners include Mr A. Neil from the UK, Mr. E. Delvaux from Belgium, Mr Lengal from the Czech Republic, Mr H. Bijlsma from the Netherlands, and Mr G. Pfaff from Germany. All should be receiving their packages soon. Lets wish them some interesting findings with their projects.
December 15, 2011 | Texas instruments | 222901974
Unique Ser/Des technology supports encrypted video and audio content with full duplex bi-directional control channel over a single wire interface.