Periodic Reporting for period 4 - SERSing (Advanced Surface Enhanced Raman Spectroscopy (SERS) based technologies for gas and liquids sensING in the area of chemical protection)
Periodo di rendicontazione: 2023-07-01 al 2024-06-30
Despite sustained efforts over the past decade or more, there has yet to be developed effective instrumentation for detecting and guiding responses to CBRN threats in public spaces. The SERSing project entails the development of novel handheld or robot-mounted instrumentation for near-real-time or on-demand detection/identification of chemical threats coupled with advanced algorithms to aid responders and incident commanders in hazard assessment and decision-making. It involves a team of four leading European academic groups, two high-tech companies (SME) with demonstrated expertise in advanced sensing and lab-on-chip (LoC) technologies, as well as two stakeholders (end users) responsible for CBRN and civil protection. The proven capabilities of Surface Enhanced Raman Spectroscopy (SERS) are exploited, and the system miniaturized and optimized via novel engineering designs and smart nanostructures to provide the necessary analytical core of the instrument. Gas and liquid samples are collected and delivered to the microfluidic platforms on demand or by a triggering signal; SERS analysis is performed, and chemicals identified rapidly; and results are fed into a remote monitoring station equipped with fusion algorithms that provides options for response/action, if necessary. We have coined the term “SERSing” to represent this new SERS based approach (Sensing, Evaluating, Responding, Securing).
The 2017 EU CBRN Action Plans to enhance preparedness against CBRN security risks (COM(2017) 610) and support the protection of public spaces (COM(2017) 612) emphasizes the need to strengthen Chemical Security with a focus on preparing for, and responding to chemical incidents and terrorism attacks. The tactical importance arises from shorter response times, shorter on-site assessment times, and faster recovery and restoration times. Research and innovation is essential to keeping up with evolving security needs.
The 2017 EU CBRN Action Plans to enhance preparedness against CBRN security risks (COM(2017) 610) and support the protection of public spaces (COM(2017) 612) emphasizes the need to strengthen Chemical Security with a focus on preparing for, and responding to chemical incidents and terrorism attacks. The tactical importance arises from shorter response times, shorter on-site assessment times, and faster recovery and restoration times. Research and innovation is essential to keeping up with evolving security needs.
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
• 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
According to the International Forum to Advance First Responder Innovation, first responders need technologically advanced tools and equipment that are affordable and innovative to rapidly identify, detect and analyze threats and hazards. These solutions may also include subsequent software or devices enabled to display data and analysis on an intuitive user interface. In order to improve responder safety, efficiency and effectiveness, responders need the ability to i) rapidly identify hazardous agents and contaminants; ii) understand pertinent information regarding protective actions or treatments for these threats to improve response situational awareness at incident scenes and decision-making.
The commonly used cumbersome chemical detectors are mostly based on ion mobility/mass spectrometry techniques and their acquisition prices start from 30.000$ excluding data libraries. More specific detection based on immunoassay techniques does not cover the full spectra of evolving chemical threats. Miniaturized sensors are gaining of importance but efforts on multi-sensor integration and analyses are still required to provide with reliable measurements.
The successful project yields a rugged, easy-to-use Raman-SERS kit that can be hand-held and operated by first responders wearing personal protective equipment, or mounted on a robot/drone, or emplaced at a network of fixed locations that can provide fast, trace-level detection and unequivocal identification of a wide range of chemical threats in air or liquid media encountered in real-world environments. The geo-located data are transmitted to a smart, on-line platform for rapid processing, and the information derived from the data is immediately accessible to authorized personnel for decision making and response actions/alerts. Commercialization is facilitated by the involvement of SMEs and end-users throughout the development, implementation and outreach phases of the project.
The commonly used cumbersome chemical detectors are mostly based on ion mobility/mass spectrometry techniques and their acquisition prices start from 30.000$ excluding data libraries. More specific detection based on immunoassay techniques does not cover the full spectra of evolving chemical threats. Miniaturized sensors are gaining of importance but efforts on multi-sensor integration and analyses are still required to provide with reliable measurements.
The successful project yields a rugged, easy-to-use Raman-SERS kit that can be hand-held and operated by first responders wearing personal protective equipment, or mounted on a robot/drone, or emplaced at a network of fixed locations that can provide fast, trace-level detection and unequivocal identification of a wide range of chemical threats in air or liquid media encountered in real-world environments. The geo-located data are transmitted to a smart, on-line platform for rapid processing, and the information derived from the data is immediately accessible to authorized personnel for decision making and response actions/alerts. Commercialization is facilitated by the involvement of SMEs and end-users throughout the development, implementation and outreach phases of the project.