1,721,015 research outputs found
Bioelectronic Large-Area Transistors for High-Performance Sensing
No full textBioelectronics, originating from Galvani’s eighteenth-century experiments,
blends biology, medicine, and electronics to create devices that can be
closely connected to biological systems. This review focuses on bioelectronic
large-area field-effect transistor (FET) sensing devices, emphasizing their
sensitivity, specificity, and reliability. The role of analytical chemistry in op-
timizing performance-level control is pivotal, and the review discusses key
performance metrics, including limit of identification (LOI), reliability and
selectivity. The assessment of the LOI level is addressed using examples of
FET-based bioelectronic sensors capable of detecting concentrations at least
in the picomolar range. Examples of sensors capable of detecting concen-
trations in the tens of zeptomolar range are also provided, demonstrating
that a single molecule in 0.1 mL can be reliably detected. Working at the
LOI also minimizes random errors, which can be as low as 1%. The review
also explores the use of molecularly imprinted polymers for highly selective
FET bioelectronic detections, noting their sustainability and robustness in
comparison to natural antibodies
Tailoring Functional Interlayers in Organic Field-Effect Transistor Biosensors
No full textThis review aims to provide an update on the development involving dielectric/organic semiconductor (OSC) interfaces for the realization of biofunctional organic field-effect transistors (OFETs). Specific focus is given on biointerfaces and recent technological approaches where biological materials serve as interlayers in back-gated OFETs for biosensing applications. Initially, to better understand the effects produced by the presence of biomolecules deposited at the dielectric/OSC interfacial region, the tuning of the dielectric surface properties by means of self-assembled monolayers is discussed. Afterward, emphasis is given to the modification of solid-state dielectric surfaces, in particular inorganic dielectrics, with biological molecules such as peptides and proteins. Special attention is paid on how the presence of an interlayer of biomolecules and bioreceptors underneath the OSC impacts on the charge transport and sensing performance of the device. Moreover, naturally occurring materials, such as carbohydrates and DNA, used directly as bulk gating materials in OFETs are reviewed. The role of metal contact/OSC interface in the overall performance of OFET-based sensors is also discussed
Self-powered wearable biosensor based on stencil-printed carbon nanotube electrodes for ethanol detection in sweat
No full textHerein we introduce a novel water-based graphite ink modified with multiwalled carbon nanotubes, designed for the development of the first wearable self-powered biosensor enabling alcohol abuse detection through sweat analysis. The stencil-printed graphite (SPG) electrodes, printed onto a flexible substrate, were modified by casting multiwalled carbon nanotubes (MWCNTs), electrodepositing polymethylene blue (pMB) at the anode to serve as a catalyst for nicotinamide adenine dinucleotide (NADH) oxidation, and hemin at the cathode as a selective catalyst for H2O2 reduction. Notably, alcohol dehydrogenase (ADH) was additionally physisorbed onto the anodic electrode, and alcohol oxidase (AOx) onto the cathodic electrode. The self-powered biosensor was assembled using the ADH/pMB-MWCNTs/SPG||AOx/Hemin-MWCNTs/SPG configuration, enabling the detection of ethanol as an analytical target, both at the anodic and cathodic electrodes. Its performance was assessed by measuring polarization curves with gradually increasing ethanol concentrations ranging from 0 to 50 mM. The biosensor demonstrated a linear detection range from 0.01 to 0.3 mM, with a detection limit (LOD) of 3 +/- 1 mu M and a sensitivity of 64 +/- 2 mu W mM-1, with a correlation coefficient of 0.98 (RSD 8.1%, n = 10 electrode pairs). It exhibited robust operational stability (over 2800 s with continuous ethanol turnover) and excellent storage stability (approximately 93% of initial signal retained after 90 days). Finally, the biosensor array was integrated into a wristband and successfully evaluated for continuous alcohol abuse monitoring. This proposed system displays promising attributes for use as a flexible and wearable biosensor employing biocompatible water-based inks, offering potential applications in forensic contexts.Graphical AbstractA novel water-based graphite ink modified with multiwalled carbon nanotubes designed for the development of a wearable self-powered biosensor enabling alcohol abuse detection through sweat analysis
Label-free optical biosensing at femtomolar detection limit
No full textDetection of target biomolecules has attracted a great deal of interest lately particularly when label-free techniques are involved as they can be much faster than label needing ones. As yet state-of-the-art high throughput quantitative determinations are in the sub-picomolar regime. This study is focused on the development of a highly performing biosensor based on a biofunctionalized photonic crystal (PhC) immobilized on the tip of an UVâvis optical fiber. The PhC is easily realized by self-assembly of polystyrene nano-beads on the optical fiber tip. The device performance level has been evaluated using the highly stable streptavidin-biotin binding. To this end a convenient streptavidin physisorption immobilization strategy directly on the polystyrene beads surface is herein proposed. Eventually, real time detection of biotinylated Bovine Serum Albumin (bBSA) molecules has been achieved at limit of detection (LOD) as low as 1.5 fM. Functionalized PhCs are therefore proven to be a powerful tool for the detection of biological species, down to femtomolar detection limit
An analytical model for bio-electronic organic field-effect transistor sensors (Applied Physics Letters (2013)103 (103301))
No full textA model for the electrical characteristics of Functional-Bio-Interlayer Organic Field-Effect Transistors (FBI-OFETs) electronic sensors is here proposed. Specifically, the output current-voltage characteristics of a streptavidin (SA) embedding FBI-OFET are modeled by means of the analytical equations of an enhancement mode p-channel OFET modified according to an ad hoc designed equivalent circuit that is also independently simulated with pspice. An excellent agreement between the model and the experimental current-voltage output characteristics has been found upon exposure to 5 nM of biotin. A good agreement is also found with the SA OFET parameters graphically extracted from the device transfer I-V curves
Inside out: Exploring edible biocatalytic biosensors for health monitoring
No full textEdible biosensors can measure a wide range of physiological and biochemical parameters, including temperature, pH, gases, gastrointestinal biomarkers, enzymes, hormones, glucose, and drug levels, providing real-time data. Edible biocatalytic biosensors represent a new frontier within healthcare technology available for remote medical diagnosis. The main challenges to develop edible biosensors are: i) finding edible materials (i.e. redox mediators, conductive materials, binders and biorecognition elements such as enzymes) complying with Food and Drug Administration (FDA), European Food Safety Authority (EFSA) and European Medicines Agency (EMEA) regulations; ii) developing bioelectronics able to operate in extreme working conditions such as low pH (∼pH 1.5 gastric fluids etc.), body temperature (between 37 °C and 40 °C) and highly viscous bodily fluids that may cause surface biofouling issues. Nowadays, advanced printing techniques can revolutionize the design and manufacturing of edible biocatalytic biosensors.
This review outlines recent research on biomaterials suitable for creating edible biocatalytic biosensors, focusing on their electrochemical properties such as electrical conductivity and redox potential. It also examines biomaterials as substrates for printing and discusses various printing methods, highlighting challenges and perspectives for edible biocatalytic biosensors
Ultrasensitive detection of 2,4-dichlorophenoxyacetic acid by inhibiting alkaline phosphatase immobilized onto a highly porous gold nanocoral electrode
No full textHerein, we describe the design and implementation of an ultrasensitive enzyme inhibition-based biosensor for 2,4-dichlorophenoxyacetic acid (2,4-D) detection. The biosensor utilizes alkaline phosphatase (AlP), immobilized on a photo-crosslinked polymer matrix of poly(vinyl alcohol) functionalized with N-methyl-4(4′-formylstyryl)pyridinium (PVA-SbQ), supported by electrodes coated with highly porous gold nanocorals (hPGNCs). After preliminary electrochemical and morphological characterization, the PVA-SbQ/AlP/hPGNC electrode was tested for inhibition studies employing ascorbate 2-phosphate (A2P) as the initial substrate. The biosensor preparation/sensing time from electrode preparation to final results is approximately 45 minutes, which enables the possibility to easily scale up the electrode production process on a daily basis with a reliable analytical result in only 5 minutes of amperometric measurement. Following the initial kinetic studies and evaluation of analytical performance, the PVA-SbQ/AlP/hPGNC platform demonstrated a linear detection range from 0.002 to 22 ppt, with a sensitivity of 0.121 ± 0.006 ppt−1 (RSD = 4.9%, R2 = 0.996, and N = 6) and a limit of detection (LoD) of 0.7 ppq. This sensitivity is 7–8 orders of magnitude below the regulatory thresholds in Europe and the USA. Furthermore, the biosensor was validated using 19 homogenized wheat leaf sample extracts, prepared in line with European Food Safety Authority (EFSA) guidelines, achieving average recoveries exceeding 96% and RSD values under 9.8%. The biosensor also exhibited robust operational and storage stability, maintaining 84% (30 hours of continuous operation) and 94% (120 days) of its initial response, respectively. These results highlight the potential of the PVA-SbQ/AlP/hPGNC biosensor for on-site 2,4-D monitoring in agricultural crops and its feasibility for integration with artificial intelligence for advanced diagnostics
Pyrolyzed Walnut Shell‐Based Flexible Electrodes for Magnetically Triggered ON/OFF DNA Release
No full textA magnetically gated, enzymatically driven DNA release platform based on sustainable pyrolyzed walnut shell-derived carbon electrodes is reported. Upon glucose addition under aerobic conditions, biocatalytic oxygen reduction at the cathode induces a local pH increase, resulting in electrostatic repulsion of negatively charged 5(6)-carboxyfluorescein-labeled DNA (FAM-labeled DNA). Electrochemical analysis reveals an oxygen reduction reaction (ORR) onset potential of +0.576 ± 0.003 V vs. Ag/AgCl and a maximum current of −8.2 ± 0.4 μA. Electrochemical impedance spectroscopy (EIS) confirms a post-ORR increase in interfacial resistance from 6.2 ± 0.5 to 11.1 ± 0.9 kΩ. DNA release reaches 97% after 400 min, corresponding to a surface density of 22 ± 4 nmol cm−2. A competing enzymatic gate, composed of co-immobilized glucose oxidase and catalase (GOx–CAT) on magnetic nanoparticles (MNPs), enables remote suppression of electron flow and DNA release upon application of a 0.3 T magnetic field. Under “OFF” conditions, DNA release is reduced to 1%, and anodic current decreases by 60%. The system exhibits excellent reversibility over four ON–OFF cycles with minimal performance degradation. This bioelectronic platform represents a self-powered, reversible strategy for stimuli-responsive drug release
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