Despite the potentialities of electrochemical sensors, these devices still encounter challenges in devising high-throughput and accurate drug susceptibility testing. The lack of platforms for providing these analyses over the preclinical trials of drug candidates remains a significant barrier to developing medicines. In this way, ultradense electrochemical chips are combined with machine learning (ML) to enable high-throughput, user-friendly, and accurate determination of the viability of 2D tumor cells (breast and colorectal) aiming at drug susceptibility assays.
View Article and Find Full Text PDFFlow assurance is a long-term challenge for oil and gas exploration as it plays a key role in designing safe and efficient operation techniques to ensure the uninterrupted transport of reservoir fluids. In this regard, the sensitive monitoring of the scale formation process is important by providing an accurate assessment of the minimum inhibitor concentration (MIC) of antiscale products. The optimum dosage of antiscale inputs is of pivotal relevance as their application at concentrations both lower and higher than MIC can imply pipeline blockages, critically hindering the entire supply chain of oil-related inputs and products to society.
View Article and Find Full Text PDFHigh-throughput sensors are valuable tools for enabling massive, fast, and accurate diagnostics. To yield this type of electrochemical device in a simple and low-cost way, high-density arrays of vertical gold thin-film microelectrode-based sensors are demonstrated, leading to the rapid and serial interrogation of dozens of samples (10 μL droplets). Based on 16 working ultramicroelectrodes (UMEs) and 3 quasi-reference electrodes (QREs), a total of 48 sensors were engineered in a 3D crossbar arrangement that devised a low number of conductive lines.
View Article and Find Full Text PDFNanostructured microelectrodes (NMEs) are an attractive alternative to yield sensitive bioassays in unprocessed samples. However, although valuable for different applications, nanoporous NMEs usually cannot boost the sensitivity of diffusion-limited analyses because of the enlarged Debye length within the nanopores, which reduces their accessibility. To circumvent this limitation, nanopore-free gold NMEs were electrodeposited from 45 μm SU-8 apertures, featuring nanoridged microspikes on a recessed surface of gold thin film while carrying interconnected crown-like and spiky structures along the edge of a SU-8 passivation layer.
View Article and Find Full Text PDFMultiplexing is a valuable strategy to boost throughput and improve clinical accuracy. Exploiting the vertical, meshed design of reproducible and low-cost ultra-dense electrochemical chips, the unprecedented single-response multiplexing of typical label-free biosensors is reported. Using a cheap, handheld one-channel workstation and a single redox probe, that is, ferro/ferricyanide, the recognition events taking place on two spatially resolved locations of the same working electrode can be tracked along a single voltammetry scan by collecting the electrochemical signatures of the probe in relation to different quasi-reference electrodes, Au (0 V) and Ag/AgCl ink (+0.
View Article and Find Full Text PDFThe real-time and monitoring of the synthesis of nanomaterials (NMs) remains a challenging task, which is of pivotal importance by assisting fundamental studies (e.g., synthesis kinetics and colloidal phenomena) and providing optimized quality control.
View Article and Find Full Text PDFMolybdenum disulfide (MoS) is a very promising layered material for electrical, optical, and electrochemical applications because of its unique and outstanding properties. To unlock its full potential, among different preparation routes, electrochemistry has gain interest due to its simple, fast, scalable and simple instrumentation. However, obtaining large-area monolayer MoS that will enable the fabrication of novel electronic and electrochemical devices is still challenging.
View Article and Find Full Text PDFImpedimetric wearable sensors are a promising strategy for determining the loss of water content (LWC) from leaves because they can afford on-site and nondestructive quantification of cellular water from a single measurement. Because the water content is a key marker of leaf health, monitoring of the LWC can lend key insights into daily practice in precision agriculture, toxicity studies, and the development of agricultural inputs. Ongoing challenges with this monitoring are the on-leaf adhesion, compatibility, scalability, and reproducibility of the electrodes, especially when subjected to long-term measurements.
View Article and Find Full Text PDFThe diagnosis of cancer and other diseases using data from non-specific sensors - such as the electronic tongues (e-tongues) - is challenging owing to the lack of selectivity, in addition to the variability of biological samples. In this study, we demonstrate that impedance data obtained with an e-tongue in saliva samples can be used to diagnose cancer in the mouth. Data taken with a single-response microfluidic e-tongue applied to the saliva of 27 individuals were treated with multidimensional projection techniques and non-supervised and supervised machine learning algorithms.
View Article and Find Full Text PDFShedding synchrotron light on microfluidic systems, exploring several contrasts in situ/operando at the nanoscale, like X-ray fluorescence, diffraction, luminescence, and absorption, has the potential to reveal new properties and functionalities of materials across diverse areas, such as green energy, photonics, and nanomedicine. In this work, we present the micro-fabrication and characterization of a multifunctional polyester/glass sealed microfluidic device well-suited to combine with analytical X-ray techniques. The device consists of smooth microchannels patterned on glass, where three gold electrodes are deposited into the channels to serve in situ electrochemistry analysis or standard electrical measurements.
View Article and Find Full Text PDFThe sensing field has shed light on an urgent necessity for field-deployable, user-friendly, sensitive, and scalable platforms that are able to translate solutions into the real world. Here, we attempt to meet these requests by addressing a simple, low-cost, and fast electrochemical approach to provide sensitive assays that consist of dropping a small volume (0.5 μL) of off-the-shelf alcohols on pyrolyzed paper-based electrodes before adding the sample (150 μL).
View Article and Find Full Text PDFThe monitoring of toxic inorganic gases and volatile organic compounds has brought the development of field-deployable, sensitive, and scalable sensors into focus. Here, we attempted to meet these requirements by using concurrently microhole-structured meshes as (i) a membrane for the gas diffusion extraction of an analyte from a donor sample and (ii) an electrode for the sensitive electrochemical determination of this target with the receptor electrolyte at rest. We used two types of meshes with complementary benefits, i.
View Article and Find Full Text PDFThis paper addresses an important breakthrough in the high mass production of liposomes by microfluidics technology. We investigated the synthesis of liposomes using a high flow rate microfluidic device (HFR-MD) with a 3D-twisted cross-sectional microchannel to favor chaotic advection. A simple construction scaffold technique was used to manufacture the HFR-MD.
View Article and Find Full Text PDFMicrochannels can be used to simulate xylem vessels and investigate phytopathogen colonization under controlled conditions. In this work, we explore surface functionalization strategies for polydimethylsiloxane and glass microchannels to study microenvironment colonization by Xylella fastidiosa subsp. pauca cells.
View Article and Find Full Text PDFReady-to-use sensing probes have been used to develop a rapid-production, low-cost, fast and sensitive electronic tongue, which consists of electric double-layer microfluidic capacitors. Pencil graphite cores consisting of rough flake-graphite with various ratios of graphite, clay and wax assured differential interactions towards pattern recognition applications.
View Article and Find Full Text PDFReduced graphene oxide (rGO) layers are known to be significantly conductive along the basal plane throughout delocalized sp domains. Defects present in rGO implies in disordered systems with numerous localized sites, resulting in a charge transport governed mainly by a 2D variable range hopping (VRH) mechanism. These characteristics are observed even in multilayered rGO since the through-plane conduction is expected to be insubstantial.
View Article and Find Full Text PDFThis technical note describes a new microfluidic sensor that combines low-cost (USD $0.97) with rapid fabrication and user-friendly, fast, sensitive, and accurate quantification of a breast cancer biomarker. The electrodes consisted of cost-effective bare stainless-steel capillaries, whose mass production is already well-established.
View Article and Find Full Text PDFThe unique electronic, mechanical and optical properties of graphene make it a remarkable 2D material, widely explored in a plethora of applications. However, graphene zero-bandgap and the production of defect-free pristine graphene in large areas still limit some applications. To circumvent these issues, graphene-derived 2D materials have arisen as attractive candidates for low-dimensional systems, which requires a better comprehension of their properties.
View Article and Find Full Text PDFDistillation is widely used in industrial processes and laboratories for sample pre-treatment. The conventional apparatus of flash distillation is composed of heating source, distilling flask, condenser, and receiving flask. As disadvantages, this method shows manual and laborious analyses with high consumption of chemicals.
View Article and Find Full Text PDFThe challenge of the early diagnosis of pancreatic cancer in routine clinical practice requires low-cost means of detection, and this may be achieved with immunosensors based on electrical or electrochemical principles. In this paper, we report a potentially low-cost immunosensor built with interdigitated gold electrodes coated with a self-assembled monolayer and a layer of anti-CA19-9 antibodies, which is capable of detecting the pancreatic cancer biomarker CA19-9 using electrical impedance spectroscopy. Due to specific, irreversible adsorption of CA19-9 onto its corresponding antibody, according to data from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), the immunosensor is highly sensitive and selective.
View Article and Find Full Text PDFAdvances in nanomaterials have led to tremendous progress in different areas with the development of high performance and multifunctional platforms. However, a relevant gap remains in providing the mass-production of these nanomaterials with reproducible surfaces. Accordingly, the monitoring of such materials across their entire life cycle becomes mandatory to both industry and academy.
View Article and Find Full Text PDFGraphene is a breakthrough 2D material due to its unique mechanical, electrical, and thermal properties, with considerable responsiveness in real applications. However, the coverage of large areas with pristine graphene is a challenge and graphene derivatives have been alternatively exploited to produce hybrid and composite materials that allow for new developments, considering also the handling of large areas using distinct methodologies. For electronic applications there is significant interest in the investigation of the electrical properties of graphene derivatives and related composites to determine whether the characteristic 2D charge transport of pristine graphene is preserved.
View Article and Find Full Text PDFElectronic tongues (e-tongues) are promising analytical devices for a variety of applications to address the challenges of quality control in water monitoring and industries of foods, beverages, and pharmaceuticals. A crucial drawback in the current e-tongues is the need to recalibrate the device when one or more sensing units (usually with modified surface) are replaced. Another downside is the necessity to perform subsequent surface modifications and analyses to each of the diverse sensing units, undermining the simplicity and velocity of the method.
View Article and Find Full Text PDFThe fast growth of celiac disease diagnosis has sparked the production of gluten-free food and the search for reliable methods to detect gluten in foodstuff. In this paper, we report on a microfluidic electronic tongue (e-tongue) capable of detecting trace amounts of gliadin, a protein of gluten, down to 0.005 mg kg in ethanol solutions, and distinguishing between gluten-free and gluten-containing foodstuff.
View Article and Find Full Text PDFIn this study, we introduce a simple protocol to manufacture disposable, 3D-printed microfluidic systems for sample preparation of petroleum. This platform is produced with a consumer-grade 3D-printer, using fused deposition modeling. Successful incorporation of solid-phase extraction (SPE) to microchip was ensured by facile 3D element integration using proposed approach.
View Article and Find Full Text PDF