Assessing the health of tissues deep inside the body is a major need and challenge in medicine. Imaging modalities such as MRI, CT, and ultrasound provide very little information about the composition and environment of tissues being examined.
Now, researchers at the University of Edinburgh, Heriot-Watt University, and Bath University, all in the UK, have developed an ultra-thin probe, similar to a fine piece of hair, that can measure the pH and oxygen concentration deep within the lungs. The same technology, slightly modified, has potential in other parts of the body, such as the inner ear, GI tract, and various interstitial spaces.
The photonic optrode relies on a chemical transducer for its action. It can obtain results in near real-time, which allows clinicians to quickly examine their patients. In a test on the distal alveolar space of the lungs, the researchers were able to obtain the pH and oxygen concentration with impressive accuracy.
Their device, only .2 mm in diameter, actually supports 19 different sensors, with room for more. In the current study, the researchers chose only certain types of sensor, but other sensors can be readily integrated into the probe for specific applications.
“These new methods, if taken to clinic, will lead to novel insights in disease biology,” said Dr. Michael Tanner, of the University of Edinburgh and Heriot-Watt University. “Our aim now is to expand the number of unique sensors on this miniaturized platform to provide even more information.”
Image caption: Optrode fabrication and characterization. (A) Bright-field image of a fiber (viewed from the side) with etched pits (~10 µm in depth). (B) Fluorescence image (excitation 488 nm and emission 520 nm) of the etched fibers (viewed from the side) after the pH sensors (fluorescein-based) were loaded into the pits. Note the focal plane of image in (B) is different from (A) to highlight the loaded cores. (C,D) SEM images of an etched optical fiber before and after the addition of the microspheres. The scale bar in all the images is 50 µm.
Study in Scientific Reports: High fidelity fibre-based physiological sensing deep in tissue
