Periodic Reporting for period 1 - VolThinSens (VolThinSens. Challenging societal needs involving ions detection: New strategies for the development of Voltammetry ion Sensors based on Thin membranes)
Reporting period: 2018-11-01 to 2021-04-30
Modern society is evolving to a scenario in which all daily activities will be monitored using smart sensors. The provision of rapid, reliable and decentralized data is crucial, and chemical sensors are potential candidates to disrupt into the current digitalization era. The VolThinSens project has put forward an innovative sensing strategy for reliable detection of ions in different contexts. The project has built up innovative fundamental knowledge to solve the traditional bottleneck for electrochemical sensors to reach real sample analysis. Thus, VolThinSens has investigated a series of new ion sensing methodologies considering voltammetric ultrathin membranes as the key element to provide a wide application perspective. Successful proof-of-concepts in the project cover EU priorities such as “citizens’ welfare” and “protecting nature”, aiming to enhance EU excellence and competitiveness in pharmacological/clinical control as well as water issues through the provision of relevant chemical observations. The overall objectives of the VolThinSens project have targeted the exploration of adequate materials to fabricate the sensors and indeed considering sustainability principles; development of innovative electrochemical readouts designed towards the best performances; and demonstration of the analytical application of the sensors in clinical/pharmacological and environmental domains.
The VolThinSens project has developed a series of sensors working on the basis of ultrathin ion-selective membranes whose analytical capabilities are tuned via the different membrane elements. Particular attention was devoted to the evaluation of the redox mediator promoting the ion-transfer event at the sample-membrane interface, which is responsible for the sensor response towards the analyte level in the sample [Electrochimica Acta 315 (2019) 84; Analytical Chemistry 92 (2020) 14085]. Importantly, different strategies have ended up in the detection of relevant ions in clinical and environmental samples (lithium, chloride, ammonium and silver), but also the detection of biomolecules (creatinine and glycine) was unexpectedly addressed with the new concepts developed in the project frame [Biosensors & Bioelectronics 130 (2019) 110; Analytical Chemistry 92 (2020), 3315; Biosensors & Bioelectronics 182 (2021) 113154]. Of special attention are the efforts put forward towards the attainment of improved selectivity and limit of detection of ions by means of membranes with reduced exchanged capability, new ionophores and membrane materials with minimum footprint and enhanced biocompatibility as well as accumulative readouts [Sensors & Actuators B 297 (2019) 126781; ACS Sensors 4 (2019) 2524; Analyst 145 (2020) 3188; Sensors & Actuators B 321 (2020) 128453]. All in all, the project’s results point out the potential of the new sensors towards unprecedented chemical information that will be obtained in a totally decentralized fashion as soon as the sensing concepts converge with the appropriate electronics and measure devices. Beyond the scientific papers already published in peer-reviewed journals and some still in progress, the project’s outcomes have been mainly communicated via conferences and workshops, social media, websites and other (industrial and public) events. Furthermore, the researcher–supervisor–host alliance formed within the VolThinSens project has permitted to advance knowledge in other additional domains such as food analysis [Analyst 145 (2020) 3645], water quality [Analytical Chemistry 91 (2019) 14951; Sensors & Actuators B 334 (2021) 129635] and wearable sensors [Sensors 19 (209) 363; Analytical Chemistry 91 (2019) 8644; Analytical Chemistry 92 (2020) 14085] in where the developed sensors based on ultrathin membranes may have a future (and very interesting) exploitation.
The VolThinSens project found its inspiration in previous investigations by the principal investigator. These were based on voltammetry membranes backside contacted with a thin film of a redox active polymer that modulates any ion-transfer event at the sample-membrane interface. Preliminary research manifested a clear potential towards new ion sensing platforms, yet with rather rudimentary knowledge about the working principle and the directions to be followed for an appropriate development of the concept at that time. Now, the VolThinSens project has demonstrated notable progress beyond the state of the art and placing Voltammetry Thin layer membrane Sensors (VolThinSens) on the top of the current wave of chemical information digitization by means of electrochemistry techniques. The strategical combination of materials, fundamental mechanisms and electrochemically controlled readouts has led to the tangible proof that certain challenging societal needs involving ions detection can be successfully addressed. In particular, the results in VolThinSens demonstrate the possibility to gain insight into pharmaceutical fabrication control according to establish policies and patients control in real time, contributing hence to the EU social welfare. It is also feasible to collect information related to biogeochemical processes relevant to understand EU aquatic systems, but also for predictions of toxicological impact, to protect ecosystems and human health assuring a sustainable management (EU policy and legislation) as well as prevention of economic losses. Overall, the interpretation of any observation provided by the sensors developed in VolThinSens is expected to contribute to the materialization of EU pharmacological, clinical and environmental (but also others) directives concerning relevant information, impact assessments, preventing and remedying damage, official regulations, monitoring if legislation and reporting of infringements, among others.