BIO-PIX: development of next-generation photonic biosensors

The principal investigator of the project is Muhammad Ali Butt, PhD, Assistant Professor at the Institute of Microelectronics and Optoelectronics, Faculty of Electronics and Information Technology. He is an internationally established researcher in the fields of integrated photonics, nanophotonics, and optical biosensing, and the author of over 220 scientific publications in leading international journals. His research focuses on the design, fabrication, and experimental implementation of photonic integrated circuits for biodetection, optical communications, and lab-on-a-chip technologies. The BIO-PIX team also includes Bartosz Janaszek, PhD Eng., and Marcin Kieliszczyk, M.Sc. Eng. The project is carried out in collaboration with researchers from the Faculty of Chemistry at Warsaw University of Technology and the CEZAMAT Centre for Advanced Materials and Technologies.

The main goal of the BIO-PIX project is to develop a new generation of integrated photonic biosensors capable of detecting disease biomarkers with unprecedented sensitivity, precision, and reliability.

"The work includes the design, fabrication, and experimental validation of an innovative silicon nitride-based biosensing platform utilizing a novel architecture: an asymmetric Mach–Zehnder interferometer terminated with a loop-mirror Sagnac reflector (a-LT-MZI). By combining advanced photonic engineering with highly selective molecular recognition chemistry, these biosensors will enable real-time detection of extremely low concentrations of clinically relevant biomarkers without requiring fluorescent or radioactive labels," says Dr Muhammad Ali Butt from the Faculty of Electronics and Information Technology, principal investigator of the project. "This technology holds significant potential for the early diagnosis of inflammatory conditions, autoimmune disorders, infectious diseases, and cancer, as well as for the development of compact point-of-care diagnostic systems."

An interdisciplinary project

A defining feature of the BIO-PIX project is its interdisciplinary nature, bringing together researchers from the Institute of Microelectronics and Optoelectronics, CEZAMAT, and the Faculty of Chemistry at Warsaw University of Technology. The project integrates competencies in integrated photonics, nanotechnology, biosensing, analytical chemistry, and molecular recognition, covering the complete research workflow—from photonic device engineering and biochemical interface development to experimental validation.

Researchers from the Institute of Microelectronics and Optoelectronics are responsible for the design, numerical optimization, electromagnetic modelling, and optical characterization of photonic integrated circuits and nanophotonic devices. The CEZAMAT team handles the fabrication of the designed photonic circuits. At the same time, scientists from the Faculty of Chemistry contribute expertise in surface functionalization, receptor layer engineering, and the immobilization of biological molecules to enable highly selective detection of disease biomarkers. This close synergy between engineering and chemical sciences enables a comprehensive, interdisciplinary approach to developing next-generation biosensors.

The research will explore advanced photonic waveguide technologies, including sub-wavelength grating (SWG) waveguides, slot waveguides, and one-dimensional photonic crystal (1D-PhC) waveguides. These will be integrated into the novel a-LT-MZI platform to maximize light-matter interaction and significantly boost biosensor sensitivity. The developed devices will be optimized for label-free detection of clinically significant biomarkers, including C-reactive protein (CRP) and selected microRNAs that play crucial roles in inflammatory processes and early disease diagnosis. Successful deployment of these technologies will yield a versatile biosensing platform that is easily adaptable to other biomedical targets and, in the future, to applications in environmental monitoring and food safety.

Beyond its scientific objectives, the BIO-PIX project aims to enhance the international research reputation of Warsaw University of Technology by advancing expertise in integrated photonics, biosensing, and interdisciplinary studies. Combining advanced photonic engineering with molecular chemistry, the team strives to build a robust technological platform for future optical biosensors that are compact, highly sensitive, and ready for real-world deployment. The outcomes of the BIO-PIX project are set to contribute significantly to next-generation diagnostic technologies while solidifying the University's position as a leading centre for research and innovation in integrated photonics and biomedical sensing.