Fiber Optic Biosensor-integrated Microfluidic Chip to Detect Glucose Levels
WASHINGTON–(BUSINESS WIRE)–Insulin deficiency and hyperglycemia are two well-known culprits behind diabetes, both of which are reflected in blood glucose concentrations. Now, researchers are working to create ultrasensitive lab-on-a-chip devices to quickly measure glucose concentrations with the goal of developing device for early diagnosis and prevent of diabetes. A team of researchers from The Hong Kong …
WASHINGTON–(BUSINESS WIRE)–Insulin deficiency and hyperglycemia are two well-known culprits behind
diabetes, both of which are reflected in blood glucose concentrations.
Now, researchers are working to create ultrasensitive lab-on-a-chip
devices to quickly measure glucose concentrations with the goal of
developing device for early diagnosis and prevent of diabetes.
A team of researchers from The Hong Kong Polytechnic University and
Zhejiang University in China report integrating fiber optic glucose
sensors into a microfluidic chip to create portable, high-performance,
low-cost devices for measuring glucose levels in a paper published this
week in the journal Biomedical
Optics Express, from The
Optical Society (OSA).
“Today, photonic approaches are recognized as the most promising
techniques for ultrasensitive sensing,” said Dr. A. Ping Zhang,
associate professor, Department of Electrical Engineering, The
Hong Kong Polytechnic University. “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.”
One reason microfluidic chip technology is so appealing is that it
provides a tiny platform to integrate sensors with functional
components, such as microfluidic mixers, in order to achieve a
lab-on-a-chip analysis system for fast and reliable results.
While electrochemical glucose biosensors can be integrated into
microfluidic channels to develop easy-to-handle, low-cost, and portable
microfluidic chips, electroactive interference problems often appear in
electrochemical sensors. But fiber optic sensors offer a solution to
this issue, thanks to their immunity to electromagnetic interference.
By combining a new fiber optic biosensor with a microfluidic chip, Zhang
and colleagues created an interference-free optofluidic device for
ultrasensitive detection of glucose levels.
Their method involves “fabricating an optical fiber ‘long-period
grating’ (LPG) with a period of 390 microns within a small-diameter
optical fiber with a cladding diameter of 80 microns,” he explained.
“Such fiber optic devices induce strong co-directional mode coupling
through a resonant scattering process. And the resulting central
wavelength is very sensitive to changes of the refractive index (RI) of
the surrounding media via the evanescent field of optical fiber cladding
mode.”
To transform the fiber optic RI sensor into a glucose sensor, the team
selected glucose oxidase as a sensing material that would react with
glucose in solution. “To support the sensing film and magnify RI change,
a pH-responsive multilayer film of polyethylenimine (PEI) and
polyacrylic acid (PAA) is deposited on the side surface of the LPG
sensor before immobilization of the sensing film,” Zhang noted.
The PEI/PAA multilayer film “surveils the oxidation of glucose with the
gluclose oxidase catalyst and responds to the reaction via swelling or
contracting,” he added.
Experimental results revealed that the new fiber optic sensor “is very
sensitive on its own and can detect glucose oxidase concentrations as
low as 1 nM (10-9 molarity),” he said. But, after integration
into the microfluidic chip, the sensor’s performance was “remarkably
further improved in terms of detection range and response time.”
Also, notably, “no significant loss of biomolecular activity was
observed during the experiments, which implies that our layer-by-layer
self-assembly technique renders a robust electrostatic absorption of
glucose oxidase within the sensing film,” Zhang said.
The team’s work “is a significant step toward developing optofluidic
devices for the early diagnosis and prevention of diabetes,” he said.
In terms of applications, the optofluidic device enables detection of
glucose in solution — requiring only a tiny droplet of sweat. “This
makes it an extremely appealing technology to develop for early
diagnosis of diabetes via monitoring glucose content within sweat,”
Zhang said.
Their ultimate goal is to develop multifunctional “lab-on-a-chip”
devices — through the integration of photonics, microfluidics, and
functional materials onto a small chip. “Such a technology will enable a
broad range of research and development in biomedical diagnostics,
environmental monitoring and even aid drug discovery,” he noted.
Paper: Ming-jie Yin, Bobo Huang, Shaorui Gao, A. Ping Zhang, and
Xuesong Ye, “Optical
fiber LPG biosensor integrated microfluidic chip for ultrasensitive
glucose detection,” Biomed. Opt. Express 7, 2067-2077 (2016).
DOI: 10.1364/BOE.7.002067.
About Biomedical Optics Express
Biomedical Optics Express is OSA’s principal outlet for
serving the biomedical optics community with rapid, open-access,
peer-reviewed papers related to optics, photonics and imaging in the
life sciences. The journal scope encompasses theoretical modeling and
simulations, technology development, and biomedical studies and clinical
applications. It is published by The Optical Society and edited by
Christoph Hitzenberger of The Medical University of Vienna. Biomedical
Optics Express is an open-access journal and is available at no
cost to readers online at: OSA
Publishing.
About The Optical Society
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information, visit osa.org/100.