Conference Agenda

Mid-infrared sensor technology plays an increasingly important role in modern biodiagnostics, in particular in (pre)clinical screening and monitoring scenarios. Non-invasive exhaled breath analysis based on mid-infrared (MIR; 3-20 µm) photonics ranges among the most flexible sensing solutions for addressing molecular constituents and biomarkers within the exhaled breath matrix. In particular, with the emergence of quantum and interband cascade laser (QCL, ICL) technology along with interband cascade LEDs (IC-LEDs) along with

advanced waveguide concepts such as substrate-integrated hollow waveguides (iHWGs) integrated MIR sensing solutions for portable usage are on the horizon. The discussion of latest MIR photonic technologies in this presentation will be augmented by highlight biomedical applications including testing for long-COVID and bacterial infections in exhaled breath underlining the utility of next-generation mid-infrared biophotonics.

We present a four-dimensional (4D) Surface Plasmon Resonance (SPR) Imaging biosensor for real-time, array based high-through biomolecular bindings detection. The sensor measures the sensitive phase change induced spectral colour variation at plasmonic resonance with imaging device. It captures two-dimensional biomolecular bindings signal in the time-domain with spectral colour space information (4D imaging data), while no complex phase extraction is required. In the experiment, measurements for refractive index (RI) samples in 1.3330-1.3455 RIU were performed and the sensor RI resolution was found to be 7.2 x 10-6 RIU. The sensor was further demonstrated for antibodies molecular bindings detection in a 5 x 5 array format and 25 biomolecular binding interactions were monitored in real-time. In on-going works, we apply the imaging biosensor for Monkeypox virus neutralizing antibodies detection, which can contribute to Monkeypox virus vaccination development.

Genetically encoded voltage indicators (GEVIs) allow high-throughput and high-resolution measurements of electrical activity in mammalian cells through membrane voltage modulated fluorescence. Recently, bright, fast and photostable GEVIs have been developed, mostly though directed evolution. However, low voltage sensitivity still severely limits the signal to noise ratio of voltage measurements with GEVIs. This impedes massive parallel recording of membrane voltages and places high demands on imaging hardware. Through rational protein engineering, we have developed a novel rhodopsin-based voltage sensor with a sensitivity of over 200%, far surpassing current state of the art voltage sensors. By optimizing the kinetics of this new sensor, we hope to enable voltage recordings with unprecedented fidelity.

An optical fibre sensor with a long period grating (LPG) is described for the binding protein FKBP12 detection. An ad-hoc synthesized recognition element is immobilised on the fibre surface in correspondence of the LPG by using a home-made microfluidic flow-cell. Measurement is performed by flowing solutions in the flow-cell with increasing FKBP12 concentration and measuring the shift of the LPG resonant peak.

A nanoplasmonic biosensor is presented based on periodic arrays of gold nanoprisms, engineered for high-sensitivity and label-free detection of biomolecular interactions. Integrated within a microfluidic platform, the biosensor is designed to operate under well-controlled culture conditions, enabling real-time analysis of cytokine secretion from live cells. Our system offers superior sensitivity compared to conventional techniques while simplifying the detection workflow by eliminating the need for fluorescent markers. The optical configuration is fully compatible with standard inverted microscopes, making it ideal for widespread adoption in biological laboratories. Furthermore, the compact and modular design facilitates integration into organ-on-chip systems for monitoring the dynamic behaviour of healthy and diseased cells in co-culture environments, paving the way for advanced biomedical research and personalized diagnostics