Improving biosensors for implantable use

July 24, 2018, Ecole Polytechnique Federale de Lausanne
Alice Gillen and Nils Schürgers, two of the paper's authors, making sensor gels out of the new DNA-nanotube complexes. Credit: Alessandra Antonucci

EPFL scientists have developed new nanotube biosensors using synthetic biology, which improves their sensing capabilities in complex biofluids, such as blood and urine. The study is published in the Journal of Physical Chemistry Letters.

Biosensors are devices that can detect biological moleculesin air, water, or blood. They are widely used in drug development, medical diagnostics, and biological research. The growing need for continuous, real-time monitoring of biomarkers in diseases like diabetes is currently driving efforts to develop efficient and portable devices.

Some of the most promising optical biosensors currently being developed are made using single-walled carbon . The near-infraredlight emission of the carbon nanotubes lies within the optical transparency window of biological materials. This means water, blood, and tissue such as skin do not absorb the emitted light, making these biosensors ideal for implantable sensing applications. These sensors can thus be placed underneath the skin and the optical signal can still be detected without the need to have electrical contacts piercing through the surface.

However, the omnipresence of salts in biofluids creates a pervasive challenge in designing the implantable devices. Fluctuations in salt concentrations that naturally occur in the body have been shown to affect the sensitivity and selectivity of optical sensors based on wrapped with single-stranded DNA.

In order to overcome some of these challenges, a team of researchers from the lab of Ardemis Boghossianat EPFL engineered stable optical nanotube sensors using . The use of synthetic biology imparts increased stability to the optical biosensors, making them more suitable for use in biosensing applications in complex fluids such as blood or urine and even inside the human body.

"What we did was wrap nanotubes with 'xeno' nucleic acids (XNA), or synthetic DNA that can tolerate the variation in salt concentrations that our bodies naturally undergo, to deliver a more stable signal," says Ardemis Boghossian. Alice Gillen, the lead author of the paper, led the efforts in studying how certain salts affect the optical emission of the biosensors.

The study covers varying ion concentrations within the physiological ranges found in common biofluids. By monitoring both the intensity of the nanotubes' signal and shifting of the signal's wavelength, the researchers were able to verify that the bioengineered sensors showed greater stability over a larger range of salt concentrations than the DNA sensors traditionally used in the field.

"This is really the first time a true synthetic biology approach is being used in the field of nanotube optics," says Boghossian. "We think these results are encouraging for developing the next generation of optical biosensors that are more promising for implantable sensing applications such as continuous monitoring."

Explore further: New biosensor benefits from melding of carbon nanotubes, DNA

More information: Alice J. Gillen et al. Xeno Nucleic Acid Nanosensors for Enhanced Stability Against Ion-Induced Perturbations, The Journal of Physical Chemistry Letters (2018). DOI: 10.1021/acs.jpclett.8b01879

Related Stories

New biosensor benefits from melding of carbon nanotubes, DNA

November 15, 2011

Purdue University scientists have developed a method for stacking synthetic DNA and carbon nanotubes onto a biosensor electrode, a development that may lead to more accurate measurements for research related to diabetes and ...

Biosensors for bladder cancer diagnosis

April 17, 2018

Cancer constitutes one of the leading causes of mortality worldwide. As early diagnosis is paramount to improved clinical outcome and survival, sensitive diagnostics capable of detecting cancer-related molecules are necessary.

Team develos new process for manufacturing SWCNT films

February 19, 2018

In a finding that could accelerate the development of next-generation wearable and flexible electronics, a team of Skoltech scientists led by Professor Albert Nasibulin has discovered a revolutionary means of improving the ...

Recommended for you

How to mass produce cell-sized robots

October 23, 2018

Tiny robots no bigger than a cell could be mass-produced using a new method developed by researchers at MIT. The microscopic devices, which the team calls "syncells" (short for synthetic cells), might eventually be used to ...

Nanosized ferroelectrics become a reality

October 22, 2018

Using ferroelectricity instead of magnetism in computer memory saves energy. If ferroelectric bits were nanosized, this would also save space. But conventional wisdom dictates that ferroelectric properties disappear when ...

Taking steps toward a wearable artificial kidney

October 17, 2018

There just aren't enough kidney transplants available for the millions of people with renal failure. Aside from a transplant, the only alternative for patients is to undergo regular dialysis sessions to clear harmful cellular ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.