Early disease detection in body fluids with photonic biosensors

Addressing this challenge, a Fraunhofer research team from Fraunhofer IPMS, Fraunhofer IZI, and Fraunhofer IOF is developing disposable biosensors. These biosensors provide rapid results and extensive multiplexing capabilities, enabling early disease detection and potentially transforming healthcare.

The detection method hinges on specialised bioassays created by Fraunhofer IZI. These assays involve antigen molecules binding specifically to sensor surfaces functionalised with capture molecules. The molecule binding causes a resonance wavelength shift in the biosensor chip’s transmission spectra.

The biosensors feature specially developed, scalable on-chip multichannel micro-ring resonator architectures, with up to seven sensors designed for a wavelength of 1550nm. They are manufactured on a silicon nitride waveguide platform on 200mm silicon wafers, using a CMOS-compatible process in Fraunhofer IPMS's advanced clean room facilities. To enhance sensitivity, new sensor designs operating in the visible range are being developed, incorporating micro-ring resonators and Mach-Zehnder interferometers in unique combinations. This results in cost-efficient, scalable sensors with customised design, high precision, and reliability.

The team has already created a portable demonstrator based on a multi-channel silicon nitride micro-ring resonator biosensor system. This system, allowing for easy chip exchange via special solutions for light coupling and detection, enables multiplex detection of specific miRNA biomarkers related to neurodegenerative and oncological diseases. DNA-based capture molecules immobilised on the sensor surface detect these biomarkers. The developed sensors and integrated system are versatile, suitable for detecting nucleic acids, various disease-associated biomarkers, and pathogens in different fluids.

These biosensors hold great promise for rapid, minimally invasive diagnostics, particularly in early disease detection, therapy monitoring, and drug development. The team plans to collaborate with diagnostics companies and clinics to further develop these biosensors for significant biomedical applications. The goal is to demonstrate their practical use in the healthcare sector in the near future, potentially revolutionising diagnostics and patient care.