Navigation Links
Biochip measures glucose in saliva, not blood

PROVIDENCE, R.I. [Brown University] For the 26 million Americans with diabetes, drawing blood is the most prevalent way to check glucose levels. It is invasive and at least minimally painful. Researchers at Brown University are working on a new sensor that can check blood sugar levels by measuring glucose concentrations in saliva instead.

The technique takes advantage of a convergence of nanotechnology and surface plasmonics, which explores the interaction of electrons and photons (light). The engineers at Brown etched thousands of plasmonic interferometers onto a fingernail-size biochip and measured the concentration of glucose molecules in water on the chip. Their results showed that the specially designed biochip could detect glucose levels similar to the levels found in human saliva. Glucose in human saliva is typically about 100 times less concentrated than in the blood.

"This is proof of concept that plasmonic interferometers can be used to detect molecules in low concentrations, using a footprint that is ten times smaller than a human hair," said Domenico Pacifici, assistant professor of engineering and lead author of the paper published in Nano Letters, a journal of the American Chemical Society.

The technique can be used to detect other chemicals or substances, from anthrax to biological compounds, Pacifici said, "and to detect them all at once, in parallel, using the same chip."

To create the sensor, the researchers carved a slit about 100 nanometers wide and etched two 200 nanometer-wide grooves on either side of the slit. The slit captures incoming photons and confines them. The grooves, meanwhile, scatter the incoming photons, which interact with the free electrons bounding around on the sensor's metal surface. Those free electron-photon interactions create a surface plasmon polariton, a special wave with a wavelength that is narrower than a photon in free space. These surface plasmon waves move along the sensor's surface until they encounter the photons in the slit, much like two ocean waves coming from different directions and colliding with each other. This "interference" between the two waves determines maxima and minima in the light intensity transmitted through the slit. The presence of an analyte (the chemical being measured) on the sensor surface generates a change in the relative phase difference between the two surface plasmon waves, which in turns causes a change in light intensity, measured by the researchers in real time.

"The slit is acting as a mixer for the three beams the incident light and the surface plasmon waves," Pacifici said.

The engineers learned they could vary the phase shift for an interferometer by changing the distance between the grooves and the slit, meaning they could tune the interference generated by the waves. The researchers could tune the thousands of interferometers to establish baselines, which could then be used to accurately measure concentrations of glucose in water as low as 0.36 milligrams per deciliter.

"It could be possible to use these biochips to carry out the screening of multiple biomarkers for individual patients, all at once and in parallel, with unprecedented sensitivity," Pacifici said.

The engineers next plan to build sensors tailored for glucose and for other substances to further test the devices. "The proposed approach will enable very high throughput detection of environmentally and biologically relevant analytes in an extremely compact design. We can do it with a sensitivity that rivals modern technologies," Pacifici said.

Tayhas Palmore, professor of engineering, is a contributing author on the paper. Graduate students Jing Feng (engineering) and Vince Siu (biology), who designed the microfluidic channels and carried out the experiments, are listed as the first two authors on the paper. Other authors include Brown engineering graduate student Steve Rhieu and undergraduates Vihang Mehta, Alec Roelke.


Contact: Richard Lewis
Brown University

Related biology news :

1. Sensor biochips could aid in cancer diagnosis and treatment
2. Reportlinker Adds Global Biochip Markets: Microarrays and Lab-on-a-Chip
3. Reportlinker Adds Global Biochip Markets: Microarrays and Lab-on-a-Chip
4. ReportsnReports - Biochips Market, Nuclear Medicine Market, Medical Imaging Market Research
5. NIAID announces 25 new awards to develop radiation countermeasures
6. Ecologists report quantifiable measures of natures services to humans
7. Updated formula measures kidney function more accurately
8. Free online toolkit provides standard measures for genome and population studies
9. Illinois Soil Nitrogen Test measures microbial nitrogen
10. Cost-effective measures could stop child pneumonia deaths
11. Broecker: What we need are tougher measures against climate change
Post Your Comments:
Related Image:
Biochip measures glucose in saliva, not blood
(Date:11/12/2015)... -- A golden retriever that stayed healthy despite having the ... a new lead for treating this muscle-wasting disorder, report ... MIT and Harvard and the University of São Paolo ... Cell, pinpoints a protective gene that boosts muscle ... Boston Children,s lab of Lou Kunkel , PhD, ...
(Date:11/10/2015)... 10, 2015 About signature ... helps to identify and verify the identity of ... as the secure and accurate method of authentication ... particular individual because each individual,s signature is highly ... when dynamic signature of an individual is compared ...
(Date:10/29/2015)... Oct. 29, 2015   MedNet Solutions , an ... spectrum of clinical research, is pleased to announce that ... Association (MHTA) as one of only three finalists for ... – Small and Growing" category. The Tekne Awards honor ... shown superior technology innovation and leadership. ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... ALEXANDRIA, Va. , Dec. 1, 2015 ... provides senior debt to life sciences and healthcare services ... senior secured term loan with MDRejuvena, Inc. ("the Company"). ... commercialization and continued development of the Company,s Rejuvaphyl™ and ... --> Rejuvaphyl is the MDRejuvena brand of high ...
(Date:12/1/2015)... , ... December 01, 2015 , ... ... announces Park NX10 SICM Module, an add-on scanning ion conductance microscopy module to ... of SICM to an AFM. , Park SICM benefits virtually all materials characterization ...
(Date:12/1/2015)... , Dec. 1, 2015 Cepheid (Nasdaq: ... its participation at the Piper Jaffray Healthcare Conference in ... morning, the Company is reaffirming its outlook for the ... 2016, in addition to discussing longer term business model ... Chief Executive Officer.  "We continue to be the fastest ...
(Date:12/1/2015)... , December 1, 2015 ... addition of the  "2016 U.K. Virology and ... Forecasts for 100 Tests, Supplier Shares by ...  report to their offering.  --> ... the  "2016 U.K. Virology and Bacteriology Testing ...
Breaking Biology Technology: