Researchers invent a new nano-optical biosensor

Biosensors are important diagnostic devices that must be fast, inexpensive and easy to use. If the biosensor is compact and can be operated autonomously, it can be used from the doctor to the patient itself, so the value is very high. Most optical biosensors require a broad range of light colors as a basis (like a rainbow) to operate reliably, and the need for a wide range of light colors makes the sensors bulky, expensive, and more complex. Most biosensors today require a spectrometer to extract data from each light color, limiting their usefulness. Scientists at EPFL have proposed a new concept that allows a single color of light to operate as a simple imaging detector. Despite using only a single color of light, the system provides extremely accurate biosensing information, as if an entire rainbow of colors illuminate the sensor. The new biosensor uses two specific capabilities, including nanophotonics and data science techniques. The chips themselves are built from nanostructures made of silicon. Nanostructured silicon surfaces with features around 100 nanometers can more efficiently capture light at the biological sample/chip interface. This makes the biosensor extremely sensitive to the presence of biomarkers, leading to noticeable changes in the signature of the incident light. This feature is known as the light intensity of the collected light"quantity"The change. Typically, a camera continuously receives light passing through the biochip, acquiring intensity information from the biochip for millions of image pixels. Images of biomarkers and intensity changes on the nanostructures attached to the biochip are compiled at very high resolution from the induced intensity changes at each pixel. The researchers used data science techniques combined with pre-recorded performance maps to process light intensity information from a large number of pixels. The system considers the efficiency of each pixel and adjusts its contribution to the final reading in a collective manner. The researchers likened the process to coming to a solid conclusion by carefully weighing their knowledge in the field after receiving input from a group of experts. Scientists on the project created a demonstration of cancer diagnosis using a new biosensor that detects tumor exons, which are biomarkers of early-stage cancer. The team determined that the image-based biosensor could monitor breast cancer exons in real time over a broad detection range, making it clinically relevant for both healthy and sick people.