#implantable

Alice Gillen and Nils Schürgers, two of the paper’s authors, making sensor gels out of the new DNA-nanotube complexes. Credit: Alessandra Antonucci

Biosensors are devices that can detect biological molecules in 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 biosensor devices.

Some of the most promising optical biosensors currently being developed are made using single-walled carbon nanotubes. The near-infrared light 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 single-walled carbon nanotubes wrapped with single-stranded DNA.

In order to overcome some of these challenges, a team of researchers from the lab of Ardemis Boghossian at EPFL engineered stable optical nanotube sensors using synthetic biology. 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.”

Source : EPFL

ICL eye surgery in Ambala. ICL is an implantable lens that works with the natural lens of your eye to improve your vision During the procedure, the lens is inserted between your iris and your natural lens through a tiny incision that usually does not require any stitches ICL surgery can permanently reduce your dependence on glasses or contact lenses.

LASIK Eye Surgery today is a safe and effective method of correcting nearsightedness, farsightedness and astigmatism for the vast majority of patients seeking Laser Vision Correction of their refractive eye conditions. In fact, LASIK surgery is by far the most common procedure to help those wishing to eliminate their dependence on eyeglasses and contact lenses. However, for some patients who are extremely nearsighted or myopic, those that have thin corneas or those that have other conditions that might predispose them to complications with LASIK, another alternative might be to find out if they are good candidates for Implantable Lenses to correct their vision. One such lens is the Verisyse Phakic Intraocular Lens and another is the VisianT Implantable Collamer Lens (ICL).