| 1. |
- Ding, R., et al.
(författare)
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Gold-modified paper as microfluidic substrates with reduced biofouling in potentiometric ion sensing
- 2021
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 344
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Tidskriftsartikel (refereegranskat)abstract
- Microfluidic sampling media based on paper and its modifications with either gold nanoparticles or sputtered gold were evaluated for potentiometric determination of Na+, K+, and Cl– ions in clinically relevant samples. The measurements were conducted in comparison to other commonly considered microfluidic substrates, i.e. sponge, polyester textile, and polyamide textile. Ion determination was done by using solid-contact ion-selective electrodes based on plasticized PVC membranes for Na+, K+, and Cl– ions and utilizing PEDOT(PSS) or PEDOT(Cl) as the ion-to-electron transducer. The solid-contact ion-selective electrodes and a solid-state reference electrode were placed directly on the substrate into which the sample solution was wicked. Transport of bovine serum albumin (BSA) through the paper substrate was studied by ellipsometry. Modification of the paper substrates by gold nanoparticles (AuNPs) was found to slow down the transport of BSA through the paper, when compared with unmodified paper substrates and when compared with all the other alternative sampling matrices studied. The retention of BSA obtained with AuNP-modified paper substrates significantly improved the accuracy of the potentiometric ion determinations in sweat, saliva, artificial tears, and artificial serum. The potentiometric results were validated by inductively coupled plasma optical emission spectrometry (ICP-OES) and ion chromatography (IC). The study indicates that modification of paper by AuNPs is a feasible approach to reduce biofouling of sensors that are used in the paper-based analysis of clinically relevant samples. © 2021 Elsevier B.V.
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| 2. |
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| 3. |
- Hoang, Van Chinh, et al.
(författare)
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Franz cells for facile biosensor evaluation : A case of HRP/SWCNT-based hydrogen peroxide detection via amperometric and wireless modes
- 2021
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 191
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Tidskriftsartikel (refereegranskat)abstract
- Reducing animal use in biosensor research requires broader use of in vitro methods. In this work, we present a novel application of Franz cells suitable for biosensor development and evaluation in vitro. The work describes how Franz cell can be equipped with electrodes enabling characterization of biosensors in close proximity to skin. As an example of a sensor, hydrogen peroxide biosensor was prepared based on horseradish peroxidase (HRP)/single-walled carbon nanotube (SWCNT)-modified textile. The electrode exhibited lower detection limit of 0.3 μM and sensitivity of 184 μA mM−1 cm−2. The ability of this biosensor to monitor H2O2 penetration through skin and dialysis membranes was evaluated in Franz cell setup in amperometric and wireless modes. The results also show that catalase activity present in skin is a considerable problem for epidermal sensing of H2O2. This work highlights opportunities and obstacles that can be addressed by assessment of biosensors in Franz cell setup before progressing to their testing in animals and humans.
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| 4. |
- Larpant, Nutcha, et al.
(författare)
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Sensing by wireless reading Ag/AgCl redox conversion on RFID tag : universal, battery-less biosensor design
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Massive integration of biosensors into design of Internet-of-Things (IoT) is vital for progress of healthcare. However, the integration of biosensors is challenging due to limited availability of battery-less biosensor designs. In this work, a combination of nanomaterials for wireless sensing of biological redox reactions is described. The design exploits silver nanoparticles (AgNPs) as part of the RFID tag antenna. We demonstrate that a redox enzyme, particularly, horseradish peroxidase (HRP), can convert AgNPs into AgCl in the presence of its substrate, hydrogen peroxide. This strongly changes the impedance of the tag. The presented example exploits gold nanoparticle (AuNP)-assisted electron transfer (ET) between AgNPs and HRP. We show that AuNP is a vital intermediate for establishing rapid ET between the enzyme and AgNPs. As an example, battery-less biosensor-RFID tag designs for H2O2 and glucose are demonstrated. Similar battery-less sensors can be constructed to sense redox reactions catalysed by other oxidoreductase enzymes, their combinations, bacteria or other biological and even non-biological catalysts. In this work, a fast and general route for converting a high number of redox reaction based sensors into battery-less sensor-RFID tags is described.
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| 5. |
- Ramonas, E., et al.
(författare)
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Revising catalytic “acceleration” of enzymes on citrate-capped gold nanoparticles
- 2021
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Ingår i: Journal of Catalysis. - : Elsevier. - 0021-9517 .- 1090-2694. ; 404, s. 570-578
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, many papers have reported a catalytic “acceleration” of enzymes when immobilized on gold nanoparticles. Concordantly, gold nanoparticles are often considered as an inert and safe nanomaterial, and are widely used for various purposes, e.g., experiments with humans are being conducted in vivo. In this work we have carried out an in-detail study of catalytic properties of citrate-capped gold nanoparticles and gold nanoparticle-protein conjugates using three model proteins – enzymes glucose oxidase and catalase, and catalytically inactive protein bovine serum albumin. Catalytic properties were studied at different protein-nanoparticle ratios. UV–Vis, DLS, AFM and ζ potential measurements confirmed protein-nanoparticle conjugate formation. Catalytic activity measurements were conducted using oxygen electrode and the data were analyzed by modeling the activity of conjugates. The designed experiments demonstrated that gold nanoparticles form stable conjugates with all the investigated proteins, yet they do not increase catalytic activity of the investigated enzymes – in certain conditions gold nanoparticles mimic enzymatic reactions, which may be misattributed to accelerated enzymatic catalysis. Additionally, we present specific key points demonstrating why it may be difficult to differentiate between enzyme- and gold nanoparticle-catalyzed reactions, as well as suggest specific measurements enabling better differentiation. We do not claim that enzymes cannot be accelerated on nanoparticles in general, but rather emphasize, that experimental results demonstrating atypical catalytic performance of enzymes on nanoparticles should be interpreted with additional care, and a widely propagated view of “inert gold nanoparticles” should probably be reconsidered.
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| 6. |
- Ruzgas, Tautgirdas, et al.
(författare)
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Wireless, Battery-less Biosensors Based on Direct Electron Transfer Reactions
- 2019
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Ingår i: ChemElectroChem. - : John Wiley & Sons. - 2196-0216. ; 6:20, s. 5167-5171
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Forskningsöversikt (refereegranskat)abstract
- Studies of direct electron transfer (DET) between enzymes and electrodes, among other reasons, are aimed at designing the simplest and most efficient biosensor designs. This direction might become especially valuable for the widespread integration of biosensors in Internet-of-Things (IoT) networks. In this Minireview, the simplicity of the design of wireless biosensors based on DET is discussed. It can be concluded that DET allows construction of wireless biosensors, which require no or only a few semiconductor elements. Hopefully, some of these demonstrations will translate into competitive and useful devices strongly promoting biosensing in IoT networks.
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| 7. |
- Shafaat, Atefeh, et al.
(författare)
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A Rapidly Responsive Sensor for Wireless Detection of Early and Mature Microbial Biofilms.
- 2023
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 62:40
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Tidskriftsartikel (refereegranskat)abstract
- Biofilm-associated infections, which are able to resist antibiotics, pose a significant challenge in clinical treatments. Such infections have been linked to various medical conditions, including chronic wounds and implant-associated infections, making them a major public-health concern. Early-detection of biofilm formation offers significant advantages in mitigating adverse effects caused by biofilms. In this work, we aim to explore the feasibility of employing a novel wireless sensor for tracking both early-stage and matured-biofilms formed by the medically relevant bacteria Staphylococcus aureus and Pseudomonas aeruginosa. The sensor utilizes electrochemical reduction of an AgCl layer bridging two silver legs made by inkjet-printing, forming a part of near-field-communication tag antenna. The antenna is interfaced with a carbon cloth designed to promote the growth of microorganisms, thereby serving as an electron source for reduction of the resistive AgCl into a highly-conductive Ag bridge. The AgCl-Ag transformation significantly alters the impedance of the antenna, facilitating wireless identification of an endpoint caused by microbial growth. To the best of our knowledge, this study for the first time presents the evidence showcasing that electrons released through the actions of bacteria can be harnessed to convert AgCl to Ag, thus enabling the wireless, battery-less, and chip-less early-detection of biofilm formation.
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| 8. |
- Shafaat, Atefeh
(författare)
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Atefeh Shafaat : Introduction...
- 2023
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Ingår i: Angewandte Chemie International Edition. - : John Wiley & Sons. - 1433-7851 .- 1521-3773. ; 62:45
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Shafaat, Atefeh
(författare)
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Development of Wireless Biosensors Integrated into the Radio Frequency Antenna for Chipless and Battery-less Monitoring of Biological Reactions
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Development of wireless sensors and biosensors is currently experiencing a rapid progress with a substantial focus directed toward highlighting their potential applications as non-invasive wearables, implants, and highly mobile point-of-care devices. Integration of wireless biosensors into the Internet of Things (IoT) is widely acknowledged as a technological advancement with the potential to significantly change daily life. To maximize this potential, simple integration of biosensors with wireless communication elements would be advantageous. In this regard, systems functioning in chipless, and battery-less modes outperform integrated circuit (IC) based and battery-powered wireless biosensors. Nevertheless, the accessibility of these wireless designs is still limited. In this study, we present a novel approach where incorporating silver nanoparticles(AgNPs) as a part of the radio frequency (RF) tag antenna enables the realization of simple, chipless, and battery-less wireless sensing of biological oxidation and reduction reactions. We exemplified the mechanism of operation in such systems by electronic wiring of enzymes through direct electron transfer (DET) and microorganisms through mediated electron transfer (MET) to the redox conversion of Ag/AgCl. The wiring was designed to facilitate the transformation of metallic AgNPs into AgCl (Ag → AgCl) or the conversion of AgCl particles back into metallic AgNPs (AgCl → Ag) when the enzymatic/microorganism based electron transfer reactions were present. These reactions occurring on the biosensor RF tag antenna strongly changed the impedance of the tag, which was wirelessly monitored by a radio frequency identification (RFID) reader. The functionality of the proposed setup in direct electron transfer coupling of the enzymatic reactions to the redox conversion of the Ag/AgCl was demonstrated by wireless detection of glucose in whole blood samples and hydrogen peroxide penetrated through the skin membrane using the enzymes glucose dehydrogenase(GDH) and horseradish peroxidase (HRP). Additionally, the capability of the proposed configuration in mediated electron transfer wiring of microorganisms to the Ag/AgCl electrochemistry was shown by wireless monitoring of medically relevant microbial biofilms in simulated wound fluid. Generalizing, the results of this work, for the first time, demonstrated that exploiting Ag/AgCl as a part of the tag antenna allows simple, chipless, and battery-less wireless sensing of biological oxidation and reduction reactions.
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| 10. |
- Shafaat, Atefeh, et al.
(författare)
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Glucose-to-Resistor Transduction Integrated into a Radio-Frequency Antenna for Chip-less and Battery-less Wireless Sensing
- 2022
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Ingår i: ACS Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 7:4, s. 1222-1234
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Tidskriftsartikel (refereegranskat)abstract
- To maximize the potential of 5G infrastructure in healthcare, simple integration of biosensors with wireless tag antennas would be beneficial. This work introduces novel glucose-to-resistor transduction, which enables simple, wireless biosensor design. The biosensor was realized on a near-field communication tag antenna, where a sensing bioanode generated electrical current and electroreduced a nonconducting antenna material into an excellent conductor. For this, a part of the antenna was replaced by a Ag nanoparticle layer oxidized to high-resistance AgCl. The bioanode was based on Au nanoparticle-wired glucose dehydrogenase (GDH). The exposure of the cathode-bioanode to glucose solution resulted in GDH-catalyzed oxidation of glucose at the bioanode with a concomitant reduction of AgCl to highly conducting Ag on the cathode. The AgCl-to-Ag conversion strongly affected the impedance of the antenna circuit, allowing wireless detection of glucose. Mimicking the final application, the proposed wireless biosensor was ultimately evaluated through the measurement of glucose in whole blood, showing good agreement with the values obtained with a commercially available glucometer. This work, for the first time, demonstrates that making a part of the antenna from the AgCl layer allows achieving simple, chip-less, and battery-less wireless sensing of enzyme-catalyzed reduction reaction.
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