Main achievements:
• A framework was set up to ensure efficient procedures of test and evaluation (T&E) of prototype and its components that will be performed later in the project.
• Preparation of SERS substrates (3x3 mm2, 5x5 mm2) by spin coating of colloidal plasmonic nanoparticles on Si chips have been scaled up at 4-inch wafer level for the PoC demonstrations.
• A new family of cost-effective flexible SERS substrates based on polycarbonate films comprising periodic nanocones coated with gold has been developed using nanoimprinting lithography and sputtering processes on 3-inch wafer level.
• Production scale up of Ag and Au nanopillar-based SERS substrates to 6-inch wafers, productions uniformity, signal improvement and cost reduction, from ~10€/chip down to ~1-3€/chip depending on the substrate type.
• Functional prototypes of periodic 3D SERS nanostructures using 4-inch wafers scale top-down fabrication techniques were realized for the first time. An improved gold nanopillar (AuNP) SERS substrate performance using atomic layer deposition techniques was achieved.
• A set of measurements in liquids to assess the performance of the Serstech 100 Indicator for detecting CWAs and other threat chemicals was performed. The obtained Raman spectra can be used as reference, and later compared to the corresponding analyte SERS spectra.
• Direct detection (label-free) of nerve agents in gas phase (GA and HD) have been demonstrated on flexible SERS substrates at ppm (GA) and ppb (HD) level with portable Raman (First Defender and BWTek) instrumentation.
• The fabrication of pre-concentration units based on microfluidic devices containing sorptive coatings (less than 5 microns thick) of selective nanoporous sorbents (Zr based MOF 808 and mesoporous silica MCM48) has been carried out and tested with surrogates and nerve agents (GA-GB) at relevant conditions.
• A resealable prototype interface concept combining the functional micro-preconcentrators, heating/cooling elements, transfer lines and miniaturized pump in a microfluidic “lab on a chip” that can be opened and resealed has been developed for delivering in a reliable way the preconcentrated gas sample to the SERS LoC for on field application.
• A Microfluidic SERS Gas Cell, based on the Micro pre-concentrator design, has been validated with core-shell plasmonic nanostructures to enable both functions: preconcentration and detection in a single chip at room temperature.
• A user-friendly handheld prototype equipped with a micro-control unit for manual operation and USB connection for Lab View Model Toolkit Interface has been developed for continuous gas detection of CWAs at room temperature. The portable prototype integrates the microfluidic SERS gas unit, electrovalves, flow and temperature sensors, heating element, transfer lines and miniaturized pump in a “reusable SERS lab on a chip” that can be actuated, interrogated with a Raman probe, and regenerated. AI algorithm based on neural network type called “Siamese network” is shows that a detection limits for SERS will be significantly lower compared to previously used methods.
• Three patent applications underway:
o Novel probe molecule (Probe 6) for SERS detection of CWA
o A SERS chip scanner with tunable focus
o A novel fabrication process for plasmonic pyramidal nanostructures with silent background and SERS performance fulfilling the SERSing metrics
