Current, emerging and future technologies for sensing the environment

This paper reviews current technologies that are used for environmental monitoring, and presents emerging technologies that will dramatically improve our ability to obtain spatially distributed, real-time data about key indicators of environmental quality at specific locations. Futuristic approaches to environmental monitoring that employ fundamental breakthroughs in materials science to revolutionise the way we monitor our environment will also be considered. In particular, approaches employing biomimetic and 'adaptive'/'stimuli-responsive' materials will be highlighted, as these could play an important role in the realization of small, low power, low cost, autonomous sensing and communications platforms that could form the building blocks of the much vaunted environmental 'sensor web'

Opportunities and challenges of using ion-selective electrodes in environmental monitoring and wearable sensors

Great opportunities exist for Ion-Selective Electrodes (ISEs) in the fields of environmental monitoring and of wearable applications for example as the sensing part in wireless networks. In this review special attention is given to the recent results obtained with Solid Contact Ion-Selective Electrodes and Solid Contact Reference Electrodes. Their combination as disposable sensing platform may offer the best solution to eliminate issues commonly experienced with ISEs and lead in a short term to their commercialization. Future research will likely focus on the miniaturization of the current devices and on the further development of non conventional potentiometric methods, e.g., controlled potential thin-layer coulometry

In-situ and remote monitoring of environmental water quality

Environmental water pollution affects human health and reduces the quality of our natural water ecosystems and resources. As a result, there is great interest in monitoring water quality and ensuring that all areas are compliant with legislation. Ubiquitous water quality monitoring places considerable demands upon existing sensing technology. The combined challenges of system longevity, autonomous operation, robustness, large-scale sensor networks, operationally difficult deployments and unpredictable and lossy environments collectively represents a technological barrier that has yet to be overcome[1]. Ubiquitous sensing envisages many aspects of our environment being routinely sensed. This will result in data streams from a large variety of heterogeneous sources, which will often vary in their volume and accuracy. The challenge is to develop a networked sensing infrastructure that can support the effective capture, filtering, aggregation and analysis of such data. This will ultimately enable us to dynamically monitor and track the quality of our environment at multiple locations. Microfluidic technology provides a route to the development of miniaturised analytical instruments that could be deployed remotely, and operate autonomously over relatively long periods of time (months–years). An example of such a system is the autonomous phosphate sensor[2] which has been developed at the CLARITY Centre, in Dublin City University. This technology, in combination with the availability of low power, reliable wireless communications platforms that can link sensors and analytical devices to online databases and servers, form the basis for extensive networks of autonomous analytical ‘stations’ or ‘nodes’ that will provide high quality information about key chemical parameters that determine the quality of our aquatic environment. The system must also have sufficient intelligence to enable adaptive sampling regimes as well as accurate and efficient decision-making responses. A particularly exciting area of development is the combination of remote satellite/aircraft based monitoring with the in-situ ground-based monitoring described above. Remote observations from satellites and aircraft can provide significant amounts of information on the state of the aquatic environment over large areas. As in-situ deployments of sensor networks become more widespread and reliable, and satellite data becomes more widely available, information from each of these sources can complement and validate the other, leading to an increased ability to rapidly detect potentially harmful events, and to assess the impact of environmental pressures on scales ranging from small river catchments to the open ocean. In this paper, we will assess the current status of these approaches, and the challenges that must be met in order to realise the vision of true internet- or global-scale monitoring of our environment. References: [1] Integration of analytical measurements and wireless communications – Current issues and future strategies. King Tong Lau, Sarah Brady, John Cleary and Dermot Diamond, Talanta 75 (2008) 606–612. [2] An autonomous microfluidic sensor for phosphate: on-site analysis of treated wastewater. John Cleary, Conor Slater, Christina McGraw and Dermot Diamond, IEEE Sensors Journal, 8 (2008) 508-515

Electrochromic properties of spiropyran-terthiophene adaptive polymers

Adaptive materials have the ability to modify their behaviour or characteristics in response to external stimuli, for example through electrochemical changes, macroscopically in the molecular structure. These materials may have only one form with binding skills whilst others are passive. In principle this material can be switched ‘on’ and ‘off’ using external stimuli [3]. In this field hybrid Polythiophenes substituted with Spiropyrans are an important representative class of conjugated polymers that form environmentally and thermally stable materials and stimulate deep interest for their optoelectronic and reversible properties. An enhancement in the electronic and photonic properties of the materials and the creation of new functions, such as new sensory materials or new biocompatible structures, critically depends on the synthesis of polythiophene [1,4]. This problem can be bypassed with some synthetically procedures that have been developed by our group and published on previous outputs. In this work the new family of hybrid spiropyran-terthiophenes moieties has been fully characterized and analyzed. An important aspect emerged in the study consists is the charge transfer during the processes of activation and deactivation of the material [2]. It has been observed spectroelectrochemically that a consistent charge transfer occurs while the activated surface is stimulated with an external potential. The kinetics of activation and deactivation has been detected at different potentials. This plays a remarkable role in the complete description of the properties of the structure under different conditions, especially during the electrochemical activation of the material in an electrolytical cell. This offers the possibility of inducing dramatic changes to the bulk properties of the active system by electrochemical stimulus. Herein we present the electrochemical and spectrelectrochemical behaviour of our materials. BIBLIOGRAPHY 1. S. Gambhir, K. Wagner, D. L. Officer, Towards functionalised terthiophene-based polymers. Synthetic Metals 154, 2005: 117-120. 2. S. Hammes-Schiffer, A. V.Soudakov. Proton-coupled electron transfer in solution, Proteins and electrochemistry. Journal of Physical Chemistry B, 2008, 14108-14123. 3. A. Radu, S. Scarmagnani, R. Byrne, C. Slater, K. T. Lau, D. Diamond, Photonic modulation of surface properties: a novel concept in chemical sensing. Journal of Physics D: Applied Physics, 40, 2007, 7238-7244. 4. H. Mehenni, L. H. Dao, Synthesis and characterization of novel conducting homopolymers based on β-styryl terthiophene. Canadian Journal of Chemistry, 86, 2008, 1010-1018

Electro- and photo- chromism of hybrid conducting polymers

Polythiophenes are an important representative class of conjugated polymers that form some of the most environmentally and thermally stable materials that can be used as electrical conductors, nonlinear optical devices, polymer LEDs, electrochromic windows, sensors, solar cells, polymer electronic interconnects, nanoelectronic and optical devices.1 Gaining control over the structure, properties, and function in polythiophenes continues to make the synthesis of polythiophenes a critical subject in the development of new advanced materials. An enhancement in the electronic and photonic properties of the materials and the creation of new functions, such as new sensory materials, critically depends on the synthesis of the polythiophene.4 This leads to the exciting prospect that the properties of polythiophenes can be selectively engineered through synthesis and assembly. Herein, we show the incorporation of molecular photochromic switches, such as benzospiropyran, into the polythiophene backbone. These are an intriguing class of organic molecules, which allow the control of molecular structure and function with light.2, 3 This offers the possibility of inducing dramatic changes to the bulk properties of a system by photonic irradiation. More importantly, benzospiropyran forms photo- reversible transition metal ion complexes. Herein, we present our work on the electro-chemical and optical properties of these hybrid materials

Materials based sensing and control

Despite the huge efforts and investments in biosensor research and development over several decades, implantable devices capable of providing long-term continuous monitoring of key molecular markers are far from realisation. The reasons relate to fundamental materials challenges such as biocompatibility, and practical barriers such as in-situ calibration. While the management of many chronic health conditions could benefit from scientific and technological breakthroughs that would advance our capabilities in this regard, perhaps the best known is the management of diabetes, due to the scale of the problem, its increasing scale and the huge impact on people, society and our health systems. Today, the state of the art is around 10-15 days continuous monitoring via devices that are attached to the body, and monitor glucose in interstitial fluid via a very fine filament that penetrates through the skin to access the sample fluid. Examples include the Abbott Freestyle Libre (https://www.freestylelibre.ie) and the Dexcom G6 Technologies (http://dexcom.eu/). The Abbott sensor allows the data to be transferred to a proprietary hand-held device whereas the Dexcom sensor transmits the data to more conventional platforms (mobile phones, iWatch etc.). Pressure to improve the offering from the increasingly IT literate user community is pushing these platforms towards much closer integration with mainstream IOT technologies. For example, tech-savvy parents of children with Type 1 Diabetes have set up their own technology group, and produced their own information management system called Nightscout, which has more advanced features than the industry systems. The Nightscout Project (http://www.nightscout.info/) is now driving technology advances in Continuous Glucose Monitoring (CGM), at least on the informatics side. Nightscout is an open source, DIY project that allows real time access to CGM data via a personal website, smartwatch viewers, or apps and widgets available for smartphones (Tagline “#WeAreNotWaiting”!). These disruptive developments are also going to create a major demand for improved sensor performance, which places an increasing focus on how to dramatically extend the functional lifetime of such biosensors, and in turn demands new thinking around the fundamental materials science of long-term on-body/in-body biosensing and controlled therapeutics (in this case insulin) delivery. In this lecture, I will discuss these and related issues, and speculate on strategies for delivering longer-term sensing and control functions the inherent behaviour of materials rather than conventional approaches

Transdisciplinary sustainability: the council for frontiers of knowledge

This paper introduces the work and diversity of the Council for Frontiers of Knowledge (CFK). In a series of vignettes relating to the intellectual interests of some of the leading academics working with the CFK, both the mission and the trans- disciplinary oversight of the agency are explored

Dye-free, simultaneous and multianalyte optical recognition using ionic liquid-based polymeric membrane

The vast majority of chemical sensors are based on a ligand that selectively bind ion of interest. The ligand is typically incorporated within a polymer matrix. In addition to ligand, polymer membrane-based chemical sensors normally require an ion-exchanger and if detection is performed using optical spectroscopy, an additional dye. Such membrane can therefore contain up to five components (polymer, plasticizer, ligand, ion-exchanger and dye). In today’s trend of drastic miniaturization, cross-contamination of sensors and leaching of active components becomes serious issue and there are many examples of the works trying to reduce/stop the leaching. In this work we explore the potential for utilization of more universal components that can take several roles thereby reducing the actual number of active components while retaining the functionality. An interesting consequence of such approach is their generalization hence introduction of the capability for simultaneous multianalyte detection – a concept departing from traditional view of chemical sensors: "one sensor for one ion". In our work we use ionic liquids – a remarkable class of compounds that have so far find application in many application areas. We demonstrate their universality by showing that they can behave as ligands, ion-exchangers and plasticizers, all in the same time. This allows significant simplification of chemical sensors. Moreover, we demonstrate that a system containing only polymer (PVC) and ionic liquid (behaving as ligand, ion exchanger and plasticizer) is capable of simultaneous recognition of two ions in the same time. Due to the relative ease of ionic liquid synthesis, we envision design of ionic liquids whose functionality can approach today’s best ionophore-based sensors