Researchers create optofluidics biosensor to detect glucose levels in sweat

Early diagnosis and prevention of diabetes is the goal of researchers at The Hong Kong Polytechnic University and Zhejiang University in China. They have reported developing fiber-optic glucose sensors in a microfluidic chip that could be the basis of portable, accurate and inexpensive devices to measure glucose levels in sweat.

In developed economies, glucose sensing technologies for diabetics are often painful--with patch-based continuous blood glucose monitors still requiring twice-daily finger pricks for calibration. But in developing and poor nations, which are increasingly exposed to urbanization with a highly refined diet that leads to increased rates of diabetes, patient-based monitoring isn't the norm with occasional glucose testing occurring at the physician's office or lab, if at all.

An inexpensive, convenient glucose monitoring solution is a necessity--with researchers approaching the problem from all sorts of angles including glucose sensors that are implanted or in contact lenses.

A microfluidic chip for glucose detection.

This latest research was published in this week's Biomedical Optics Express from The Optical Society.

"Today, photonic approaches are recognized as the most promising techniques for ultrasensitive sensing," said Dr. A. Ping Zhang, associate professor of Department of Electrical Engineering at The Hong Kong Polytechnic University, in a statement. "In particular, the synergistic integration of photonic sensing and microfluidics led to the state-of-the-art technology known as 'optofluidics' for biological and chemical analysis."

Others have used electrochemical glucose enzyme electrodes for glucose biosensor development, but researchers argued that these are too bulky and costly for daily use. Their solution combines microfluidics chips, which offer compactness, low costs and low consumption, with optical fiber sensor technology that helps to overcome problems with electromagnetic interference that can be associated with microfluidics chips.

The fiber-optic sensor detected glucose oxidase concentrations as low as 1 nM (10-9 molarity). The combined technology also reduced the response time to 70 seconds, from 6 minutes for a microfluidic chip alone.

This "is a significant step toward developing optofluidic devices for the early diagnosis and prevention of diabetes," said Zhang. "This makes it an extremely appealing technology to develop for early diagnosis of diabetes via monitoring glucose content within sweat."

"Such a technology will enable a broad range of research and development in biomedical diagnostics, environmental monitoring and even aid drug discovery," he concluded.

- here's the release from The Optical Society
- and here is the paper