Imperial College London

DrFiratGuder

Faculty of EngineeringDepartment of Bioengineering

Reader in Intelligent Interfaces
 
 
 
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f.guder

 
 
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Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

56 results found

Gonzalez-Macia L, Li Y, Zhang K, Nunez-Bajo E, Barandun G, Cotur Y, Asfour T, Olenik S, Coatsworth P, Herrington J, Guder Fet al., 2024, NFC-enabled potentiostat and nitrocellulose-based metal electrodes for electrochemical lateral flow assay, Biosensors and Bioelectronics, Vol: 251, ISSN: 0956-5663

Rapid detection of pathogens at the point-of-need is crucial for preventing the spread of human, animal and plant diseases which can have devastating consequences both on the lives and livelihood of billions of people. Colorimetric, lateral flow assays consisting of a nitrocellulose membrane, are the preferred format today for low-cost on-site detection of pathogens. This assay format has, however, historically suffered from poor analytical performance and is not compatible with digital technologies. In this work, we report the development of a new class of digital diagnostics platform for precision point-of-need testing. This new versatile platform consists of two important innovations: i) A wireless and batteryless, microcontroller-based, low-cost Near Field Communication (NFC)-enabled potentiostat that brings high performance electroanalytical techniques (cyclic voltammetry, chronoamperometry, square wave voltammetry) to the field. The NFC-potentiostat can be operated with a mobile app by minimally trained users; ii) A new approach for producing nitrocellulose membranes with integrated electrodes that facilitate high performance electrochemical detection at the point-of-need. We produced an integrated system housed in a 3D-printed phone case and demonstrated its use for the detection of Maize Mosaic Virus (MMV), a plant pathogen, as a proof-of-concept application.

Journal article

Guder F, Collins ASP, Kurt H, Duggan C, Cotur Y, Coatsworth P, Naik A, Kaisti M, Bozkurt Oet al., 2024, Parallel, Continuous Monitoring and Quantification of Programmed Cell Death in Plant Tissue, Advanced Science, ISSN: 2198-3844

Journal article

Guder F, Coatsworth P, Bozkurt O, Cotur Y, Collins AS-P, Olenik S, Zhou Z, Naik A, Asfour T, Gonzalez-Macia L, Chao D-Yet al., 2024, Time-resolved chemical monitoring of whole plant roots with printed electrochemical sensors and machine learning, Science Advances, Vol: 10, ISSN: 2375-2548

Traditional single-point measurements fail to capture dynamic chemical responses of plants, which are complex, nonequilibrium biological systems. We report TETRIS (time-resolved electrochemical technology for plant root environment in situ chemical sensing), a real-time chemical phenotyping system for continuously monitoring chemical signals in the often-neglected plant root environment. TETRIS consisted of low-cost, highly scalable screen-printed electrochemical sensors for monitoring concentrations of salt, pH, and H2O2 in the root environment of whole plants, where multiplexing allowed for parallel sensing operation. TETRIS was used to measure ion uptake in tomato, kale, and rice and detected differences between nutrient and heavy metal ion uptake. Modulation of ion uptake with ion channel blocker LaCl3 was monitored by TETRIS and machine learning used to predict ion uptake. TETRIS has the potential to overcome the urgent “bottleneck” in high-throughput screening in producing high-yielding plant varieties with improved resistance against stress.

Journal article

Brasier N, Wang J, Dincer C, Güder F, Schauwecker I, Schaffarczyk D, Ghaffari R, Goldhahn Jet al., 2024, Next-generation digital biomarkers: continuous molecular health monitoring using wearable devices, Trends in Biotechnology, ISSN: 0167-7799

Journal article

Coatsworth P, Gonzalez-Macia L, Collins ASP, Bozkurt T, Gueder Fet al., 2023, Continuous monitoring of chemical signals in plants under stress, NATURE REVIEWS CHEMISTRY, Vol: 7, Pages: 7-25

Journal article

Adeel M, Asif K, Alshabouna F, Canzonieri V, Rahman MM, Ansari SA, Güder F, Rizzolio F, Daniele Set al., 2022, Label-free electrochemical aptasensor for the detection of SARS-CoV-2 spike protein based on carbon cloth sputtered gold nanoparticles, Biosensors and Bioelectronics: X, Vol: 12, ISSN: 2590-1370

The proliferation and transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), or the (COVID-19) disease, has become a threat to worldwide biosecurity. Therefore, early diagnosis of COVID-19 is crucial to combat the ongoing infection spread. In this study we propose a flexible aptamer-based electrochemical sensor for the rapid, label-free detection of SARS-CoV-2 spike protein (SP). A platform made of a porous and flexible carbon cloth, coated with gold nanoparticles, to increase the conductivity and electrochemical performance of the material, was assembled with a thiol functionalized DNA aptamer via S-Au bonds, for the selective recognition of the SARS-CoV-2 SP. The various steps for the sensor preparation were followed by using scanning electron microscopy, cyclic voltammetry and differential pulse voltammetry (DPV). The proposed platform displayed good mechanical stability, revealing negligible changes on voltammetric responses to bending at various angles. Quantification of SARS-CoV-2 SP was performed by DPV and chronopotentiometry (CP), exploiting the changes of the electrical signals due the [Fe(CN)6]3-/4- redox probe, when SARS-CoV-2 SP binds to the aptamer immobilized on the electrode surface. Current density, in DPV, and square root of the transition time, in CP, varied linearly with the log[ SARS-CoV-2 SP], providing lower limits of detection (LOD) of 0.11 ng/mL and 37.8 ng/mL, respectively. The sensor displayed good selectivity, repeatability, and was tested in diluted human saliva, spiked with different SARS-CoV-2 SP concentrations, providing LODs of 0.167 ng/mL and 46.2 ng/mL for DPV and CP, respectively.

Journal article

Adeel M, Cotur Y, Naik A, Gonzalez-Macia L, Guder Fet al., 2022, Face masks as a platform for wearable sensors, NATURE ELECTRONICS, Vol: 5, Pages: 719-720, ISSN: 2520-1131

Journal article

Barandun G, Gonzalez Macia ML, Lee HS, Dincer C, Guder Fet al., 2022, Challenges and opportunities for printed electrical gas sensors, ACS Sensors, Vol: 7, Pages: 2804-2822, ISSN: 2379-3694

Printed electrical gas sensors are a low-cost, lightweight, low-power and potentially disposable alternative to gas sensors manufactured using conventional methods such as photolithography, etching and chemical vapor deposition. The growing interest in Internet-of-Things, smart homes, wearable devices and point-of-need sensors has been the main driver fueling the development of new classes of printed electrical gas sensors. In this Perspective, we provide an insight into the current research related to printed electrical gas sensors including materials, methods of fabrication, and applications in monitoring food quality, air quality, diagnosis of diseases and detection of hazardous gases. We further describe the challenges and future opportunities for this emerging technology.

Journal article

Guder F, Alshabouna F, Gonzalez-Macia L, Ji-Seon K, Asfour T, Lee HS, Tan E, nunez-bajo E, Cotur Y, Coatsworth P, Barandun Get al., 2022, PEDOT:PSS-modified cotton conductive thread for mass manufacturing of textile-based electrical wearable sensors by computerized embroidery, Materials Today, Vol: 59, Pages: 56-67, ISSN: 1369-7021

The textile industry has advanced processes that allow computerized manufacturing of garments at large volumes with precise visual patterns. The industry, however, is not able to mass fabricate clothes with seamlessly integrated wearable sensors, using its precise methods of fabrication (such as computerized embroidery). This is due to the lack of conductive threads compatible with standard manufacturing methods used in industry. In this work, we report a low-cost poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-modified cotton conductive thread (PECOTEX) that is compatible with computerized embroidery. The PECOTEX was produced using a crosslinking reaction between PEDOT:PSS and cotton thread using divinyl sulfone as the crosslinker. We extensively characterized and optimized our formulations to create a mechanically robust conductive thread that can be produced in large quantities in a roll-to-roll fashion. Using PECOTEX and a domestic computerized embroidery machine, we produced a series of wearable electrical sensors including a facemask for monitoring breathing, a t-shirt for monitoring heart activity and textile-based gas sensors for monitoring ammonia as technology demonstrators. PECOTEX has the potential to enable mass manufacturing of new classes of low-cost wearable sensors integrated into everyday clothes.

Journal article

Cotur Y, Guder F, Kozlov A, Olenik S, Tanriverdi U, Asfour T, Bruyns-Haylett M, Gonzalez-Macia L, Lee HSet al., 2022, Bioinspired stretchable transducer for wearable continuous monitoring of respiratory patterns in humans and animals, Advanced Materials, Vol: 34, Pages: 1-9, ISSN: 0935-9648

A bio-inspired continuous wearable respiration sensor modeled after the lateral line system of fish is reported which is used for detecting mechanical disturbances in the water. Despite the clinical importance of monitoring respiratory activity in humans and animals, continuous measurements of breathing patterns and rates are rarely performed in or outside of clinics. This is largely because conventional sensors are too inconvenient or expensive for wearable sensing for most individuals and animals. The bio-inspired air-silicone composite transducer (ASiT) is placed on the chest and measures respiratory activity by continuously measuring the force applied to an air channel embedded inside a silicone-based elastomeric material. The force applied on the surface of the transducer during breathing changes the air pressure inside the channel, which is measured using a commercial pressure sensor and mixed-signal wireless electronics. The transducer produced in this work are extensively characterized and tested with humans, dogs, and laboratory rats. The bio-inspired ASiT may enable the early detection of a range of disorders that result in altered patterns of respiration. The technology reported can also be combined with artificial intelligence and cloud computing to algorithmically detect illness in humans and animals remotely, reducing unnecessary visits to clinics.

Journal article

Ates HC, Nguyen PQ, Gonzalez-Macia L, Morales-Narvaez E, Guder F, Collins JJ, Dincer Cet al., 2022, End-to-end design of wearable sensors, Nature Reviews Materials, ISSN: 2058-8437

Wearable devices provide an alternative pathway to clinical diagnostics by exploiting various physical, chemical and biological sensors to mine physiological (biophysical and/or biochemical) information in real time (preferably, continuously) and in a non-invasive or minimally invasive manner. These sensors can be worn in the form of glasses, jewellery, face masks, wristwatches, fitness bands, tattoo-like devices, bandages or other patches, and textiles. Wearables such as smartwatches have already proved their capability for the early detection and monitoring of the progression and treatment of various diseases, such as COVID-19 and Parkinson disease, through biophysical signals. Next-generation wearable sensors that enable the multimodal and/or multiplexed measurement of physical parameters and biochemical markers in real time and continuously could be a transformative technology for diagnostics, allowing for high-resolution and time-resolved historical recording of the health status of an individual. In this Review, we examine the building blocks of such wearable sensors, including the substrate materials, sensing mechanisms, power modules and decision-making units, by reflecting on the recent developments in the materials, engineering and data science of these components. Finally, we synthesize current trends in the field to provide predictions for the future trajectory of wearable sensors.

Journal article

Gil Rosa B, Akingbade OE, Guo X, Gonzalez-Macia L, Crone MA, Cameron LP, Freemont P, Choy K-L, Güder F, Yeatman E, Sharp DJ, Li Bet al., 2022, Multiplexed immunosensors for point-of-care diagnostic applications, Biosensors and Bioelectronics, Vol: 203, ISSN: 0956-5663

Accurate, reliable, and cost-effective immunosensors are clinically important for the early diagnosis and monitoring of progressive diseases, and multiplexed sensing is a promising strategy for the next generation of diagnostics. This strategy allows for the simultaneous detection and quantification of multiple biomarkers with significantly enhanced reproducibility and reliability, whilst requiring smaller sample volumes, fewer materials, and shorter average analysis time for individual biomarkers than individual tests. In this opinionated review, we compare different techniques for the development of multiplexed immunosensors. We review the state-of-the-art approaches in the field of multiplexed immunosensors using electrical, electrochemical, and optical methods. The barriers that prevent translating this sensing strategy into clinics are outlined together with the potential solutions. We also share our vision on how multiplexed immunosensors will continue their evolution in the coming years.

Journal article

Altay A, Learney R, Guder F, Dincer Cet al., 2022, Sensors in blockchain, TRENDS IN BIOTECHNOLOGY, Vol: 40, Pages: 141-144, ISSN: 0167-7799

Journal article

Grell M, Barandun G, Asfour T, Kasimatis M, Collins ASP, Wang J, Guder Fet al., 2021, Point-of-use sensors and machine learning enable low-cost determination of soil nitrogen, Nature Food, Vol: 2, Pages: 981-989, ISSN: 2662-1355

Overfertilization with nitrogen fertilizers has damaged the environment and health of soil, but standard laboratory testing of soil to determine the levels of nitrogen (mainly NH4+ and NO3-) is not performed regularly. Here, we demonstrate that Point-of-Use measurements of NH4+, combined with soil conductivity, pH, easily accessible weather and timing data, allow instantaneous prediction of levels of NO3- in soil (R2 = 0.70) using a machine learning model. A long short-term memory recurrent neural network model can also be used to predict levels of NH4+ and NO3- up to 12 days into the future from a single measurement at day one, with R2NH4+= 0.60 and R2NO3-= 0.70, for unseen weather conditions. Our machine learning-based approach eliminates the need of using dedicated instruments to determine the levels of NO3- in soil. Nitrogenous soil nutrients can be determined and predicted with enough accuracy to forecast the impact of climate on fertilization planning, and tune timing for crop requirements, reducing overfertilization while improving crop yields.

Journal article

Wan K, Liu Y, Santagiuliana G, Barandun G, Taroni Junior P, Guder F, Bastiaansen CW, Baxendale M, Fenwick O, Papageorgiou DG, Krause S, Zhang H, Bilotti Eet al., 2021, Self-powered ultrasensitive and highly stretchable temperature-strain sensing composite yarns, Materials Horizons, Vol: 8, Pages: 2513-2519, ISSN: 2051-6355

With the emergence of stretchable/wearable devices, functions, such as sensing, energy storage/harvesting, and electrical conduction, should ideally be carried out by a single material, while retaining its ability to withstand large elastic deformations, to create compact, functionally-integrated and autonomous systems. A new class of trimodal, stretchable yarn-based transducer formed by coating commercially available Lycra® yarns with PEDOT:PSS is presented. The material developed can sense strain (first mode), and temperature (second mode) and can power itself thermoelectrically (third mode), eliminating the need for an external power-supply. The yarns were extensively characterized and obtained an ultrahigh (gauge factor ∼3.6 × 105, at 10–20% strain) and tunable (up to about 2 orders of magnitude) strain sensitivity together with a very high strain-at-break point (up to ∼1000%). These PEDOT:PSS-Lycra yarns also exhibited stable thermoelectric behavior (Seebeck coefficient of 15 μV K−1), which was exploited both for temperature sensing and self-powering (∼0.5 μW, for a 10-couple module at ΔT ∼ 95 K). The produced material has potential to be interfaced with microcontroller-based systems to create internet-enabled, internet-of-things type devices in a variety of form factors.

Journal article

Brophy K, Davies S, Olenik S, Cotur Y, Ming D, Van Zalk N, O'Hare D, Guder F, Yetisen AKet al., 2021, The future of wearable technologies, Briefing Paper

Report

Jiang N, Tansukawat ND, Gonzalez-Macia L, Ates HC, Dincer C, Guder F, Tasoglu S, Yetisen AKet al., 2021, Low-cost optical assays for point-of-care diagnosis in resource-limited settings, ACS Sensors, Vol: 6, Pages: 2108-2124, ISSN: 2379-3694

Readily deployable, low-cost point-of-care medical devices such as lateral flow assays (LFAs), microfluidic paper-based analytical devices (μPADs), and microfluidic thread-based analytical devices (μTADs) are urgently needed in resource-poor settings. Governed by the ASSURED criteria (affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverability) set by the World Health Organization, these reliable platforms can screen a myriad of chemical and biological analytes including viruses, bacteria, proteins, electrolytes, and narcotics. The Ebola epidemic in 2014 and the ongoing pandemic of SARS-CoV-2 have exemplified the ever-increasing importance of timely diagnostics to limit the spread of diseases. This review provides a comprehensive survey of LFAs, μPADs, and μTADs that can be deployed in resource-limited settings. The subsequent commercialization of these technologies will benefit the public health, especially in areas where access to healthcare is limited.

Journal article

Olenik S, Lee HS, Guder F, 2021, The future of near-field communication-based wireless sensing, NATURE REVIEWS MATERIALS, Vol: 6, Pages: 286-288, ISSN: 2058-8437

Journal article

Ates HC, Brunauer A, von Stetten F, Urban GA, Guder F, Merkoci A, Fruh SM, Dincer Cet al., 2021, Integrated Devices for Non-Invasive Diagnostics, ADVANCED FUNCTIONAL MATERIALS, Vol: 31, ISSN: 1616-301X

Journal article

Ates HC, Yetisen AK, Guder F, Dincer Cet al., 2021, Wearable devices for the detection of COVID-19, NATURE ELECTRONICS, Vol: 4, Pages: 13-14, ISSN: 2520-1131

Journal article

Nunez-Bajo E, Collins ASP, Kasimatis M, Cotur Y, Asfour T, Tanriverdi U, Grell M, Kaisti M, Senesi G, Stevenson K, Gueder Fet al., 2020, Publisher Correction: Disposable silicon-based all-in-one micro-qPCR for rapid on-site detection of pathogens., Nature Communications, Vol: 11, Pages: 1-1, ISSN: 2041-1723

Journal article

Nunez-Bajo E, Collins ASP, Kasimatis M, Cotur Y, Asfour T, Grell M, Kaisti M, Senesi G, Stevenson K, Guder F, Tanriverdi Uet al., 2020, Disposable silicon-based all-in-one micro-qPCR for rapid on-site detection of pathogens, Nature Communications, Vol: 11, Pages: 1-10, ISSN: 2041-1723

Rapid screening and low-cost diagnosis play a crucial role in choosing the correct course of intervention when dealing with highly infectious pathogens. This is especially important if the disease-causing agent has no effective treatment, such as the novel coronavirus SARS-CoV-2, and shows no or similar symptoms to other common infections. Here, we report a disposable silicon-based integrated Point-of-Need transducer (TriSilix) for real-time quantitative detection of pathogen-specific sequences of nucleic acids. TriSilix can be produced at wafer-scale in a standard laboratory (37 chips of 10 × 10 × 0.65 mm in size can be produced in 7 h, costing ~0.35 USD per device). We are able to quantitatively detect a 563 bp fragment of genomic DNA of Mycobacterium avium subspecies paratuberculosis through real-time PCR with a limit-of-detection of 20 fg, equivalent to a single bacterium, at the 35th cycle. Using TriSilix, we also detect the cDNA from SARS-CoV-2 (1 pg) with high specificity against SARS-CoV (2003).

Journal article

Li B, Tan H, Jenkins D, Srinivasa Raghavan V, Gil Rosa B, Guder F, Pan G, Yeatman E, Sharp Det al., 2020, Clinical detection of neurodegenerative blood biomarkers using graphene immunosensor, Carbon, Vol: 168, Pages: 144-162, ISSN: 0008-6223

Accurate detection of blood biomarkers related to neurodegenerative diseases could provide a shortcut to identifying early stage patients before the onset of symptoms. The specificity, selectivity and operational requirements of the current technologies, however, preclude their use in the primary clinical setting for early detection. Graphene, an emerging 2D nanomaterial, is a promising candidate for biosensing which has the potential to meet the performance requirements and enable cost-effective, portable and rapid diagnosis. In this review, we compare graphene-based immunosensing technologies with conventional enzyme-linked immunosorbent assays and cutting-edge single molecule array techniques for the detection of blood-based neurodegenerative biomarkers. We cover the progress in electrical, electrochemical and optical graphene-based immunosensors and outline the barriers that slow or prevent the adoption of this emerging technology in primary clinical settings. We also highlight the possible solutions to overcome these barriers with an outlook on the future of the promising, graphene immunosensor technology.

Journal article

Cotur Y, Kasimatis M, Olenik S, Kaisti M, Gergiou C, Guder Fet al., 2020, Stretchable composite acoustic transducer for wearable monitoring of vital signs, Advanced Functional Materials, Vol: 30, Pages: 1-7, ISSN: 1616-301X

A highly flexible, stretchable, and mechanically robust low‐cost soft composite consisting of silicone polymers and water (or hydrogels) is reported. When combined with conventional acoustic transducers, the materials reported enable high performance real‐time monitoring of heart and respiratory patterns over layers of clothing (or furry skin of animals) without the need for direct contact with the skin. The approach enables an entirely new method of fabrication that involves encapsulation of water and hydrogels with silicones and exploits the ability of sound waves to travel through the body. The system proposed outperforms commercial, metal‐based stethoscopes for the auscultation of the heart when worn over clothing and is less susceptible to motion artefacts. The system both with human and furry animal subjects (i.e., dogs), primarily focusing on monitoring the heart, is tested; however, initial results on monitoring breathing are also presented. This work is especially important because it is the first demonstration of a stretchable sensor that is suitable for use with furry animals and does not require shaving of the animal for data acquisition.

Journal article

Kasimatis M, Nunez-Bajo E, Grell M, Cotur Y, Barandun G, Kim J-S, Guder Fet al., 2019, Monolithic solder-on nanoporous Si-Cu contacts for stretchable silicone composite sensors, ACS Applied Materials and Interfaces, Vol: 11, Pages: 47577-47586, ISSN: 1944-8244

We report a method of creating solderable, mechanically robust, electrical contacts to interface (soft) silicone-based strain sensors with conventional (hard) solid-state electronics using a nanoporous Si-Cu composite. The Si-based solder-on electrical contact consists of a copper-plated nanoporous Si top surface formed through metal-assisted chemical etching and electroplating, and a smooth Si bottom surface which can be covalently bonded onto silicone-based strain sensors through plasma bonding. We investigated the mechanical and electrical properties of the contacts proposed under relevant ranges of mechanical stress for applications in physiological monitoring and rehabilitation. We also produced a series of proof-of-concept devices, including a wearable respiration monitor, leg band for exercise monitoring and Squeeze-ball for monitoring rehabilitation of patients with hand injuries or neurological disorders, to demonstrate the mechanical robustness and versatility of the technology developed, in real-world applications.

Journal article

Maier D, Laubender E, Basavanna A, Schumann S, Guder F, Urban G, Dincer Cet al., 2019, Toward Continuous Monitoring of Breath Biochemistry: A Paper-Based Wearable Sensor for Real-Time Hydrogen Peroxide Measurement in Simulated Breath, ACS Sensors, Vol: 4, Pages: 2945-2951, ISSN: 2379-3694

Exhaled breath contains a large amount of biochemical and physiological information concerning one’s health and provides an alternative route to noninvasive medical diagnosis of diseases. In the case of lung diseases, hydrogen peroxide (H2O2) is an important biomarker associated with asthma, chronic obstructive pulmonary disease, and lung cancer and can be detected in exhaled breath. The current method of breath analysis involves condensation of exhaled breath, is not continuous or real time, and requires two separate and bulky devices, complicating the periodic or long-term monitoring of a patient. We report the first disposable paper-based electrochemical wearable sensor that can monitor exhaled H2O2 in artificial breath calibration-free and continuously, in real time, and can be integrated into a commercial respiratory mask for on-site testing of exhaled breath. To improve precision for sensing H2O2, we perform differential electrochemical measurement by amperometry in which screen-printed Prussian Blue-mediated and nonmediated carbon electrodes are used for differential analysis. We were able to measure H2O2 in simulated breath in a concentration-dependent manner in real time, confirming its functionality. This proposed system is versatile, and by modifying the chemistry of the sensing electrodes, our method of differential sensing can be extended to continuous monitoring of other analytes in exhaled breath.

Journal article

Dincer C, Bruch R, Rama E, Fernandez-Abedul MT, Merkoci A, Manz A, Urban G, Guder Fet al., 2019, Disposable sensors in diagnostics, food and environmental monitoring, Advanced Materials, Vol: 31, ISSN: 0935-9648

Disposable sensors are low‐cost and easy‐to‐use sensing devices intended for short‐term or rapid single‐point measurements. The growing demand for fast, accessible, and reliable information in a vastly connected world makes disposable sensors increasingly important. The areas of application for such devices are numerous, ranging from pharmaceutical, agricultural, environmental, forensic, and food sciences to wearables and clinical diagnostics, especially in resource‐limited settings. The capabilities of disposable sensors can extend beyond measuring traditional physical quantities (for example, temperature or pressure); they can provide critical chemical and biological information (chemo‐ and biosensors) that can be digitized and made available to users and centralized/decentralized facilities for data storage, remotely. These features could pave the way for new classes of low‐cost systems for health, food, and environmental monitoring that can democratize sensing across the globe. Here, a brief insight into the materials and basics of sensors (methods of transduction, molecular recognition, and amplification) is provided followed by a comprehensive and critical overview of the disposable sensors currently used for medical diagnostics, food, and environmental analysis. Finally, views on how the field of disposable sensing devices will continue its evolution are discussed, including the future trends, challenges, and opportunities.

Journal article

Barandun G, Soprani M, Naficy S, Grell M, Kasimatis M, Chiu KL, Ponzoni A, Guder Fet al., 2019, Cellulose fibers enable near zero-cost electrical sensing of water-soluble gases, ACS Sensors, Vol: 4, Pages: 1662-1669, ISSN: 2379-3694

We report an entirely new class of printed electrical gas sensors that are produced at near 'zero cost'. This technology exploits the intrinsic hygroscopic properties of cellulose fibers within paper; although it feels and looks dry, paper contains substantial amount of moisture, adsorbed from the environment, enabling the use of wet chemical methods for sensing without manually adding water to the substrate. The sensors exhibit high sensitivity to water soluble gases (e.g., limit-of-detection for NH3 <200 parts-per-billion) with a fast and reversible response. The sensors show comparable or better performance (especially at high relative humidity) than most commercial ammonia sensors at a fraction of their price (<$0.02 per sensor). We demonstrate that the sensors proposed can be integrated into food packaging to monitor freshness (to reduce food waste and plastic pollution) or implemented into near-field-communication tags to function as wireless, battery-less gas sensors that can be interrogated with smartphones.

Journal article

Ranunkel O, Guder F, Arora H, 2019, Soft robotic surrogate lung, ACS Applied Bio Materials, Vol: 2, Pages: 1490-1497, ISSN: 2576-6422

Previous artificial lung surrogates used hydrogels or balloon-like inflatable structures without reproducing the alveolar network or breathing action within the lung. A physiologically accurate, air-filled lung model inspired by soft robotics is presented. The model, soft robotic surrogate lung (SRSL), is composed of clusters of artificial alveoli made of platinum-cured silicone, with internal pathways for air flow. Mechanical tests in conjunction with full-field image and volume correlation techniques characterize the SRSL behavior. SRSLs enable both healthy and pathological lungs to be studied in idealized cases. Although simple in construction, the connected airways demonstrate clearly the importance of an inflatable network for capturing basic lung behavior (compared to more simplified lung surrogates). The SRSL highlights the potentially damaging nature of local defects caused by occlusion or overdistension (present in conditions such as chronic obstructive pulmonary disease). The SRSL is developed as a potential upgrade to conventional surrogates used for injury risk predictions in trauma. The deformation of the SRSL is evaluated against blast trauma using a shock tube. The SRSL was compared to other conventional trauma surrogate materials and showed greatest similarity to lung tissue. The SRSL has the potential to complement conventional biomechanical studies and reduce animal use in basic biomechanics studies, where high severity protocols are used.

Journal article

Grell M, Dincer C, Le T, Lauri A, Nunez Bajo E, Kasimatis M, Barandun G, Maier S, Cass A, Guder Fet al., 2019, Autocatalytic metallization of fabrics using Si ink, for biosensors, batteries and energy harvesting, Advanced Functional Materials, Vol: 29, Pages: 1-11, ISSN: 1616-301X

Commercially available metal inks are mainly designed for planar substrates (for example, polyethylene terephthalate foils or ceramics), and they contain hydrophobic polymer binders that fill the pores in fabrics when printed, thus resulting in hydrophobic electrodes. Here, a low‐cost binder‐free method for the metallization of woven and nonwoven fabrics is presented that preserves the 3D structure and hydrophilicity of the substrate. Metals such as Au, Ag, and Pt are grown autocatalytically, using metal salts, inside the fibrous network of fabrics at room temperature in a two‐step process, with a water‐based silicon particle ink acting as precursor. Using this method, (patterned) metallized fabrics are being enabled to be produced with low electrical resistance (less than 3.5 Ω sq−1). In addition to fabrics, the method is also compatible with other 3D hydrophilic substrates such as nitrocellulose membranes. The versatility of this method is demonstrated by producing coil antennas for wireless energy harvesting, Ag–Zn batteries for energy storage, electrochemical biosensors for the detection of DNA/proteins, and as a substrate for optical sensing by surface enhanced Raman spectroscopy. In the future, this method of metallization may pave the way for new classes of high‐performance devices using low‐cost fabrics.

Journal article

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