Nano-functionalised photonic fibre probes for next generation Bio-Chemical sensors – FUNSENS

The growing demand for reliable and robust methodology in biochemical sensing calls for continuous development and advancement of sensor technologies. The most demanding criteria for a biosensor are that it should have tremendously high sensitivity and reliability to detect biomarkers of diseases at a very low concentration and in some cases at low sample volume. More often, simultaneous detection of multiple biomarkers at very low concentration in body fluids is an added advantage for disease prognosis and to for treatment monitoring purposes. Chemical sensors for environmental monitoring, homeland security and food and process control should have high specificity, cheap, fast and in most cases it should be portable for ready to use on-fields. Newer biochemical sensing techniques are emerging due to the need for shorter sample preparation protocols and faster sensing methodology. Biochemical sensor markets will be driven by the need for high accuracy, high reliability, easy usability, and higher sensitivity even at low analyte concentrations across diverse end use applications.

In this context, FUNSENS project aim to develop a highly sensitive biochemical sensing platform using surface enhanced Raman scattering (SERS) readout coupled with novel nanostructured plasmonic materials incorporated in a specially designed photonic crystal fibre (PCF) probe. We choose to develop SERS sensing platform due to its ability to produce enhanced narrow vibrational Raman ‘fingerprint’ spectra of analytes. This feature allows for the simultaneous multiplex detection of analytes with very high sensitivity, which is not easily achievable by any of the existing methods. Conventional SERS based sensing is developed on a planar nanostructured substrates or with a colloidal metallic nanoparticles (NPs) and it lacks the sensitivity and reliability required for many cutting edge biochemical sensing applications. PCFs with axially aligned air channels that run along the length of the fibre provides an excellent platform for incorporation of liquid and gaseous analytes into it.

In this context, we propose to develop, for the first time, a disruptive design of PCF specially optimised for improving the advantages of molecular fingerprinting of Raman scattering, enormous enhancement factor of SERS, and, high reproducibility and repeatability in measurements. We aim to associate the properties of this novel PCF with the latest developments in plasmonic nanoparticles and Machine-learning based algorithms of SERS spectra processing, for developing a novel ultra-sensitive fibre-based SERS probe prototype as practical and reliable “label-free” sensing tool of biochemicals in extremely low sample volume (~nano-litre), with state-of-the-art performances in sensitivity (pico-Mole) and reliability (std < 5%). We envision to translate this into a sensor probe (as a consumable) that can be incorporated with any commercial portable Raman spectrometers (associated with advanced Raman spectra analysis software) for real life practical use at affordable cost. We aim for a nano-functionalized PCF needle that will acts as an opto-fluidic, two in one probe (for sample collection and sensing) with real translation compatibility to both medical and chemical industry.
The novel sensing performances offered by our SERS fibre-needle-probe will be demonstrated by realising several detections of biochemical in practically and relevant conditions. Choice of biomarkers are based on the input from our existing large pool of clinical collaborators and chemicals (in water, food) quality management is based on the problem statement from our industry collaborators.
To realize these ambitious goals, Singapore Bioimaging Consortium and XLIM research institute (France) are associating their multi-disciplinary expertise.