Ultra-sensitive electrical biosensor unlocks potential for instant diagnostic devices

[ Back to EurekAlert! ] Public release date: 17-Apr-2012
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Contact: Melissa Van De Werfhorst
melissa@engineering.ucsb.edu
805-893-4301
University of California - Santa Barbara

(Santa Barbara, Calif. ) 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.

Kaustav Banerjee, director of the Nanoelectronics Research Lab and professor of Electrical and Computer Engineering at UCSB, and PhD student Deblina Sarkar have 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 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.

###

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.


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[ Back to EurekAlert! ] Public release date: 17-Apr-2012
[ | E-mail | Share Share ]

Contact: Melissa Van De Werfhorst
melissa@engineering.ucsb.edu
805-893-4301
University of California - Santa Barbara

(Santa Barbara, Calif. ) 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.

Kaustav Banerjee, director of the Nanoelectronics Research Lab and professor of Electrical and Computer Engineering at UCSB, and PhD student Deblina Sarkar have 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 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.

###

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.


[ Back to EurekAlert! ] [ | E-mail | Share Share ]

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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


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Package Holidays are often the Best Deals

It isn?t always easy to find a good travel deal online or at the travel agent so it?s important for you to make sure that you are prepared to buy the deal the moment it becomes available. If you are planning to go on holiday, then you most likely would have started saving already for it. That money is what you are going to be using the moment a great deal pops into your inbox. Travel agents and travel sites all offer mailing lists to let their customers know what deals are running currently and how much time they have to take advantage of the offer.

That?s probably the biggest problem that anyone might have with these deals and as long you have that extra cash tucked away you can purchase any one of those package holidays on the spot. It?s often a tough decision to make when you are presented with it, because you are never really sure if the next deal is going to be a better one.

Travel agents are clever like that, and they are constantly on the prowl for new deals that they can offer customers that are eagerly awaiting deals to places like Thailand or Fiji. Tropical destinations are no longer just postcards and posters on walls; instead they become living memories for you because you are actually there, snorkelling over coral reefs and chasing clown fish while shouting I found Nemo! You can take your partner with you, your best friend or your entire family can come along for the trip and everyone is guaranteed to have a great time. Family specials are often available and you because you are making a big booking like that, you get access to special rates as well. That means more money to spend on eating out and fun activities to keep everybody occupied on the days that you don?t feel like going to the beach. If you are willing to search a little harder you might even be able to find a deal that includes activities for everyone as well. That means you just have to pay one price for everything and it all gets taken care of. The travel agents can arrange your visa?s when you are travelling to another country and they notify the hotels to expect your arrival on the day that you have booked in.

There is so much to offer when you search for great deals on the net and as long as you are patient and ready to buy when the perfect deal comes along, you can be sure not to miss out on the holiday of a lifetime.

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Paint Sprayers Save Homeowners Time And Money | Millionaire ...

?

An increasing amount of homeowners are taking interest in tackling a variety of do it yourself home improvement projects. More and more hardware stores are providing exciting new tools and resources that allow the easy completion of many projects in a short amount of time. Interior and exterior painting has become one of the most popular do it yourself projects around the house. While many choose to paint with traditional brushes and rollers, paint sprayers offer an alternative painting method to anyone interested in saving time and money.

Adding a fresh coat of paint to interior walls, ceilings, and doors is usually a simple way to improve the way a house looks on the inside. Years of exposure often covers walls with dirt, marks, and other types of damage. Traditional painting methods require purchasing new paint, brushes, rollers, and materials to protect furniture and floors. A simple painting project might be more expensive than expected if proper plans aren?t in place before starting the job.

Planning ahead of time is a cost-effective approach to interior and exterior painting projects. Homeowners who choose to use paint sprayers are able to complete projects faster, using a lesser amount of paint and materials. The type of sprayers that used depend on the painting project being done. Surface, coverage area, and location are key factors when selecting the correct paint and sprayer for the job. Personal preference also plays a big role when selecting tools that work best.

Spray painting techniques often leave a much nicer look than paint applied with brushes or rollers. Both high-volume and low-volume low pressure sprayers are available for a variety of applications. Using the correct tools and materials will offer the best results and make sure projects are safely completed.

Many who take on home improvement projects for the first time find themselves intimidated by various tools and equipment. Fortunately advancement of technology has provided simple and straightforward methods that make do it yourself projects an enjoyable and rewarding experience. In addition, many new methods are extremely cost-effective for homeowners. Reducing the amount of money spent on painting projects will allow free up funds for other projects.

Alternative painting methods offer a professional appearance that increases the value of a home. With a tough economy and the decline of property values, every improvement done to the home is beneficial. Not everyone is comfortable with trying new tools and equipment to complete the job, but that is perfectly fine since most traditional painting methods offer just as good as results as new ones.

There is an endless amount of resources available to anyone interested in making improvements to their home. It is wise to gather as much information as possible when planning various projects. Completing a project correctly and efficiently leaves homeowners with a sense of pride and accomplishment. Not everyone is capable of completing every single type of home improvement project, but the correct tools and knowledge can go a long way and be a helpful part of the process.

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The Real Jon Jones: A documentary takes a closer look at the champ (VIDEO)

Heading into his UFC 145 title bout with Rashad Evans, Jon Jones discusses his road to success and his journey as a son, brother, fighter, and father. Watch the whole documentary as it takes you through the many aspects of his life.

Part 1: Take a journey to Jones' hometown of Binghamton, New York where we learn about his upbringing, early life and family values.

Part 2: Jones talks about a family tragedy and how the event has shaped him as a person and as a fighter. Jones openly discusses religion and how it affects his outlook on life. We take a peek into his early career and the events that led up to his UFC light heavyweight championship.

Part 3: A look into the career ofJones and the criticism that follows him. "Is Jon Jones cocky"? Jones answers with confidence about himself as a person and as an athlete.

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Exclusive 'Moonrise Kingdom' Poster: Meet Cousin Ben!

Our Summer Movie Preview Week continues with an exclusive look at "Moonrise Kingdom" character Cousin Ben! The Wes Anderson film follows two twelve year olds who fall in love in the summer of 1965. They flee from their home island off the coast of New England and travel into the wilderness. As the Sheriff leads [...]

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Shuttle makes Washington flypast

The shuttle Discovery bolted on top of a jumbo jet

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LIVE: Discovery shuttle flies over Washington DC area

One of Nasa's iconic space shuttles has made a dramatic flypast over the centre of the US capital as it heads to its final resting place in a museum.

Discovery flew over the monuments over the National Mall in Washington DC at about 10:00 EST (14:00 GMT).

Piggy-backing on a modified Boeing 747, Discovery was flying at an altitude of just 1,500ft (457m), Nasa said.

The shuttle programme ended in 2011. Discovery will go on show at the Air and Space Museum near Dulles Airport.

The shuttle approached central Washington DC from the west, flying past Dulles Airport and Arlington, Virginia, before appearing over the National Mall.

Onlookers lined the roofs of the capital's buildings, wanting to catch a glimpse of the shuttle.

Earlier, crowds of onlookers gathered along the Florida shoreline as dawn broke on Tuesday to see the shuttle take off from Kennedy Space Center.

Cheers broke out from the estimated 2,000-strong crowd as the aircraft left the runway, the Associated Press reported.

Dozens of former shuttle workers and Nasa veterans were reported to be among the onlookers.

Discovery then passed low over a packed beach and made one final turn back over the runway at the space complex before climbing towards a cruising altitude.

The aircraft's fuselage was illuminated by the early Florida sunshine for moments before it headed out of sight on its journey up the East Coast.

Fleet leader

In Washington, would-be shuttle-watchers were being advised to gather in the National Mall, the two-mile-long public park running through the heart of the city, for a prime view of the mid-morning flyover.

Discovery was expected to descend to 1,500ft and travel over the city's Waterfront area, the Mall, and a spot near the Jefferson Memorial.

The flypast was also expected to delight onlookers at a regular plane-spotting haunt, Gravelly Point Park, just outside the city limits in Virginia.

Discovery's final destination is an annex of the Smithsonian Institute's National Air and Space Museum, situated in Virginia, close to Dulles, the main international airport serving Washington DC.

Discovery was the most-used of the shuttle fleet, flying 39 missions, and was designated the fleet leader.

It is the first of three remaining shuttles to head to a museum. Enterprise - the prototype shuttle - and Endeavour will make their final journeys later this year.

The shuttle fleet was decommissioned and the programme wound up in 2011, after 30 years in action, when construction was completed on the International Space Station.

Retirement of Nasa's iconic shuttle fleet was ordered by the US government, in part due to the high cost of maintaining the ships.

The decision leaves the country with no means of putting astronauts in orbit.

Send your pictures and videos to yourpics@bbc.co.uk or text them to 61124 (UK) or +44 7624 800 100 (International). If you have a large file you can upload here.

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Mila Kunis Denies Dating Ashton Kutcher

Actress' rep insists former 'That 70s Show' co-stars are just friends.
By Jocelyn Vena


Mila Kunis and Ashton Kutcher in Los Angeles on Sunday
Photo: Blanco/X17online.com

After Mila Kunis was spotted hanging with her former "That '70s Show" co-star Ashton Kutcher several times over the weekend, the rumor mill began to spin that the one-time onscreen couple began dating in real life.

Well, her rep is addressing the rumors and shutting them down. "They've been friends for years, and they had dinner with a bunch of friends," the rep told Celebuzz. "They're not dating."

The rep continued to Usmagazine.com that there's "definitely nothing going on there" and that "three other people" were with the twosome when they went out to dinner.

According to People.com, those other friends included "70s" co-stars Wilmer Valderrama and Laura Prepon. The former castmates will all be on hand this Sunday during Fox's 25th Anniversary special.

The friends without benefits were spotted furniture shopping and chowing down at a sushi joint for dinner in Studio City, California, over the weekend. They also were seen later hanging out at his L.A.-area bachelor pad. Adding fuel to the dating-rumor fire was the fact that Kunis tried to hide from photogs by riding in the backseat of his car.

"Ashton was touching Mila's hand, and Mila was all dressed up," observed an X17 Online photographer who saw Kutcher and Kunis at the Japanese restaurant Asanebo.

Whether or not the "Two and a Half Men" star is dating Kunis, it seems his dance card has been quite full lately. Kutcher's also been romantically linked to Rihanna, who later denied anything was happening between them, telling reporters, "I'm happy, and I'm single."

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Kimbra Talks 'Penetrating' Power Of Gotye's 'Somebody That I Used To Know'

'I don't think either of us could have predicted the success of the song,' she tells MTV News.
By Jocelyn Vena


Kimbra
Photo: MTV News

When Gotye dropped "Somebody That I Used to Know," neither he nor his collaborator on the sad breakup track, Kimbra, had any idea how the song would resonate with fans.

When Kimbra stopped by MTV News last Friday, she told us she never imagined hearing the song on primetime TV shows and seeing it on the charts. The single (off Gotye's 2011 album, Making Mirrors) was covered by Matt Bomer and Darren Criss on "Glee," and contestants on both "The Voice" and "American Idol" pinned their music industry dreams on the track.

"I don't think either of us could have predicted the success of the song," she said of Gotye (a.k.a. Wally De Backer).

"Used to Know" topped several Billboard charts, including the Alternative and Rock Songs lists, and peaked at #2 on the all-important Hot 100. And over the weekend, the duo performed the track on "Saturday Night Live."

"I knew it would resonate with people when I heard it," Kimbra said. "Wally has a really great way of penetrating an emotion. But, you know ... 'Glee' and 'The Voice' and all of these crazy pieces of exposure ... that was really out of our imagination."

What makes the song stand out on pop radio, which is driven these days by dance loops and producers like Dr. Luke and Max Martin, is that it's a mid-tempo ballad that pays homage to the kinds of songs that acts like Peter Gabriel, Phil Collins and the Police pumped out in the '80s.

"I think it's a really exciting time for pop music right now, to see such a reflective, kind of vulnerable song shoot to the top of the charts, I think it's paving the way for some really exciting artists to come through," Kimbra said. "And I hope to be one of them, in terms of putting out my record here in the States. I think Wally's doing something that's really progressive for the pop world anyway."

Kimbra's album, Vows, will be out in the U.S. on May 22.

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405 Record Store Day Preview: Worcester by The 405 Guest Writer ...

Written by Jay Platt

April 21st sees the return of Record Store Day and after 4 years of the annual event it's incredible to see how much it's grown, from just ten special releases in 2008 to around 300 this year. As well as all the releases there are of course the events in store and we've pulled together writers from all over the UK to bring you previews of what's going on across the country with Jay Platt kicking things off in Worcestershire.

Until recently, music fans in Worcestershire have been forced to acquire their sacred records from the Internet or HMV. In June 2011 Rise Worcester opened in Crowngate Shopping Centre, The City's music community rejoiced in happiness. No longer would they be forced into the dark, miserable realms of HMV. There was a new kid on the block. After a successful Christmas run, Rise is now the go-to place for new music in Worcestershire. Rise is a relatively small shop with just four employees (Emily, Lewis, Kev and Mark). Each one of them is extremely friendly, knowledgeable and can always help you find the music you want. This makes for a wonderful browsing experience.

This year is the first time ever the people of Worcestershire will see an Independent Record Store Day, and what a day they are in for. Opening earlier than usual (8:00am) on Saturday 21st April, Rise will be selling hundreds of limited edition records, hosting six in-store performances from Poetry in Numbers, The May Dolls, The One Two's, Sam Eden, Our Mutual Friend, Lewisspeltbackwards (who works for Rise) and Miles Hunt as well as giving away hundreds cupcakes and custom-made mix-CDs! Music lovers of Worcester really are getting excited. The staff at Rise speak to people on a daily basis who are counting down the days to this sacred holiday. One vinyl fan said ?Retail is tough for many businesses at the moment so it's good to see an organisation taking a positive, inclusive stance. I, for one, welcome our new retail overlords. Saturday 21st April. A day for people who love music.?

From the store's point of view, this is the best day of the year. Emily described it as being like Christmas. Today they received their first delivery in preparation for the day, and she assures me that ?From now onwards it will be a race between staff to see who can open the parcels first!? For her, Record Store Day is one of the major perks of working in an indie record shop. ?The fact that so many people get so excited about it is, to me, what a record shop is all about. People coming together because they love the same things.?

Record Store Day 2012 is going to be magical, not just in London, but in smaller cities and towns too. Rise and similar shops all over the country will be hosting instore performances from your favourite artists. On Saturday 21st April make sure you get to your local indie record shop for a day that really is for music-lovers.

For more information on Record Store Day head to www.recordstoreday.co.uk/

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