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Advanced Surface Enhanced Raman Spectroscopy (SERS) based technologies for gas and liquids sensING in the area of chemical protection

Periodic Reporting for period 1 - SERSing (Advanced Surface Enhanced Raman Spectroscopy (SERS) based technologies for gas and liquids sensING in the area of chemical protection)

Reporting period: 2020-07-01 to 2021-06-30

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 main achievements include:
• 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. The outcomes of Task 1.1 were compiled in the report D1.1 that also reviews competing DIM technologies for chemical hazards, pin-points the existing technology gap and elucidates needs and requirements the SERSing technologies shall consider. The requirements of the prototype are described in the report D1.1 - Definition of scenarios and operational requirements for DIM of chemicals.
• Different SERS substrates based on uniform Au core - Ag shell nanorods with controlled size and aspect ratio and porous moieties, i.e. microporous Zn based MOF (ZIF8) and mesoporous SiO2, with tuneable thickness have been prepared by wet-chemistry.
• Specific efforts have been carried out for the implementation of the fabrication protocol at 6” wafer level for enabling chip uniformity with enhanced SERS performance by fine tuning of pillars density, pillars height and metal thickness and the incorporation of ultra-thin dieletric layers to overcome aging and background effects.
• Production scale up to 6-inch wafers, productions uniformity, signal improvement and cost reduction, from ~10€/chip down to 2-3€/chip
• Functional prototypes of periodic 3D SERS nanostructures using 4-inch waferscale 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 predictive neural network based model that recognizes Raman spectra based on library matching has been developed.
• A set of measurements in liquids to assess the performance of the Serstech 100 Indicator for detecting CWAs (GA, GB, HD, VX, VR and VC) and other threat chemicals was performed. The obtained Raman spectra can be used as reference, and later compared to the corresponding analyte SERS spectra.
According to the International Forum to Advance First Responder Innovation (IFAFRI), 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. The instrument(s) 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. The pre-operational validation of the prototypes by means on field exercises is also addressed to provide input for the iterative and continuous upgrading of the SERSing technologies. Commercialization is facilitated by the involvement of SMEs and end-users throughout the development, implementation and outreach phases of the project.
Competences of the SERSing partners