Electronic Biosensors Research Articles

Unveiling the Electrical Properties of Hyaluronan-Coated Cancer Extracellular Vesicles Using Correlative Scanning Probe Microscopy-Based Nano-Electrical Modes.

Cancer cells produce extracellular vesicles (EVs) coated with an anionic sugar polymer, hyaluronan (HA), in the extracellular matrix. Hyaluronan is an established cancer biomarker in several cancer types. In this work, we thoroughly investigated the electrical properties of HA-coated EVs using advanced scanning probe microscopy (SPM) based nanoelectrical modes, which include EFM (electrostatic force microscopy), KPFM (Kelvin probe force microscopy), PFM (piezoresponse force microscopy) and C-AFM (conductive atomic force microscopy). Analyses revealed distinct properties for different sets of EVs regarding surface potential, charge distribution, and piezoelectric electro-mechanical response at the single-vesicle resolution. The typical electron transport capabilities are primarily driven by ions in sandwiched EV junctions. This correlative approach essentially could distinguish HA-coated cancer EVs (CEVs) from normal EV (NEVs) counterparts. The combined SPM-based nanoelectrical modes offered a multiplexed one-stop label-free solution for EV's electrical property assessments. This strategy is useful in developing EV-based bioelectronic sensors.

Wireless power-up and readout from a label-free biosensor

Wearable and implantable biosensors have rapidly entered the fields of health and biomedicine to diagnose diseases and physiological monitoring. The use of wired medical devices causes surgical complications, which can occur when wires break, become infected, generate electrical noise, and are incompatible with implantable applications. In contrast, wireless power transfer is ideal for biosensing applications since it does not necessitate direct connections between measurement tools and sensing systems, enabling remote use of the biosensors. In addition, wireless sensors eliminate the need for a battery or energy harvester, reducing the size of the sensor. As far as we are aware, this is the first report ever describing a new method for wireless readout of a label-free electronic biosensor for detecting protein biomarkers. Our results reveal that we are able to successfully detect target protein and corresponding antibodies within this wireless setup. We are able to distinguish target protein in purified samples from a blank PBS sample as a negative control by tracking gradual changes in impedance at the input of the transmitter (P-value = 0.00788). We also demonstrate real-time wireless quantification of cytokines within rheumatoid arthritis patient serum samples (P-value = 0.00891). A Fine Gaussian Support Vector Machine is also used to differentiate protein from negative controls with the highest accuracy from a dataset of 54 experiments.

β‐Sheets Orientation in Physisorbed Protein Layers

AbstractPhysisorption of antibodies onto surfaces is a low‐cost, rapid, and effective approach for immobilizing bioreceptors in applications such as bioelectronic sensors. However, there is a prevailing notion that physisorbed protein layers lack structural order, thus potentially compromising their stability and sensitivity compared to antibody films that are covalently attached to the substrate surface. This study demonstrates the preferential orientation of β‐sheets within the secondary structure of protein layers, specifically anti‐immunoglobulin G (anti‐IgG) and bovine serum albumin (BSA), when physisorbed onto gold (Au) thin films. Using polarization modulation infrared reflection‐absorption spectroscopy (PM‐IRRAS) and infrared attenuated total reflection (IR‐ATR) spectroscopy, it has been confirmed that the β‐strands in these protein layers are tilted relative to the surface normal by average angles of 75.3° ± 0.4° for anti‐IgG and of 79.3 ± 0.2° for BSA. These results are obtained by analyzing the orientation of the transition dipole moments (TDMs) associated with the amide I molecular vibrations derived from a comparison between experimental and simulated mid‐infrared spectra assuming isotropically oriented TDMs. The simulations incorporate refractive and absorption index dispersions obtained from the IR‐ATR spectra. Thus obtained findings offer valuable molecular‐level insights facilitating the design and optimization of biofunctionalized interfaces in advanced biomedical and biosensing applications.

Fabrication of PNIPAM ionogels with enhanced conductive and mechanical properties for wearable biosensor

Poly(N-isopropyl acrylamide) (PNIPAM) hydrogel, renowned for its rapid response to temperature changes, has emerged as a promising material for soft electronic and wearable biosensors. However, its practical use in wearable biosensors is hindered by challenges such as poor mechanical strength, limited conductivity, and potential biosafety concerns due to residual polymerization initiators. To overcome these limitations, an edible initiator of Vitamin C is introduced to catalyze the polymerization of NIPAM. This process is further enhanced by the addition of the biocompatible ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIm][Cl]), which accelerates polymerization and improves the hydrogel’s conductivity and mechanical properties. Experimental results demonstrate that the obtained ionic hydrogel holds significant potential for wearable biosensor applications, particularly for monitoring human physiological signals.

Low-Temperature Bonding for Heterogeneous Integration of Silicon Chips with Nanocrystalline Diamond Films.

Integrating nanocrystalline diamond (NCD) films on silicon chips has great practical significance and many potential applications, including high-power electronic devices, microelectromechanical systems, optoelectronic devices, and biosensors. In this study, we provide a solution for ensuring heterogeneous interface integration between silicon (Si) chips and NCD films using low-temperature bonding technology. This paper details the design and implementation of a magnetron sputtering layer on an NCD surface, as well as the materials and process for the connection layer of the integrated interface. The obtained NCD/Ti/Cu composite layer shows uniform island-like Cu nanostructures with 100~200 nm diameters, which could promote bonding between NCD and Si chips. Ultimately, a heterogeneous interface preparation of Si/Ag/Cu/Ti/NCD was achieved, with the integration temperature not exceeding 250 °C. The TEM analysis shows the closely packed atomic interface of the Cu NPs and deposited Ti/Cu layers, revealing the bonding mechanism.

Multichannel Bioelectronic Sensing: Binary Encoding of Environmental Contaminants

Environmental water contamination from natural and synthetic chemicals is a pressing global issue. Addressing this requires the development of portable, selective, and accurate sensors. Biosensors, particularly whole-cell bioelectronic sensors, are promising due to their ability to convert chemical signals into electrical signals via extracellular electron transfer (EET) pathways. However, these sensors typically employ a single electron transfer pathway as an electrochemical channel, limiting them to the detection of a single analyte (Atkinson et al. 2022).To expand the information content, we have developed a multichannel sensor where different chemicals regulate distinct EET pathways within a single Escherichia coli cell. One channel utilizes the flavin synthesis pathway from Bacillus subtilis (Yang Yun et al. 2017) and is controlled by a cadmium-responsive promoter (Hui et al. 2021). Another channel, the Mtr pathway from Shewanella oneidensis (Ross Daniel E. et al. 2007), is controlled by an arsenite-responsive promoter (Chen et al. 2019) through activation of cytochrome CymA expression. We exploit the differing redox potentials of these two EET pathways (Kracke, Vassilev, and Krömer 2015) to develop a redox-potential-dependent algorithm that efficiently converts analog current curves into 2-bit binary outputs. This enables our bioelectronic sensor to detect and differentiate heavy metals at EPA limits. When deployed in complex environmental water samples with lower electroactivities, our sensor effectively and accurately encodes 2-bit binary signals across various analyte conditions. Thus, our multichannel bioelectronic sensor advances the field through simultaneous detection of different chemicals by a single cell, significantly expanding information transmission from EET and helping to safeguard human and environmental health.

(Invited) Tackling Leakage, Drift, and Variation in Printed Carbon Nanotube-Based Electronic Biosensors

Semiconducting carbon nanotubes (CNTs) have been pursued for use in electronic biosensors for decades. Their all-surface molecular structure, sizeable semiconducting bandgap, and solution-phase compatibility make them highly sensitive and versatile options for transducing biomarker-related electrical signals. However, amid the thousands of reports on CNT-based electronic biosensors, very little attention has been given to identifying (let alone addressing) the impact of leakage current, signal drift, and device-to-device variation, particularly under operation in biologically relevant ionic media. This talk will present recent results focused on tackling these issues in a CNT transistor-based biosensor platform (i.e., bioFETs or ion-sensitive FETs). For instance, a variety of passivation strategies were studied to determine the role of leakage current compared to the detection signal, revealing that a bilayer epoxy/high-k dielectric stack was most effective at minimizing deleterious leakage. The influence of signal drift, particularly in strong ionic solutions (e.g., 1X PBS), was also found to play a significant role in many previous reports of CNT-based biosensors that were characterized by sequential biomarker concentration spikes. Finally, strategies for addressing device-to-device variation in these biosensors will be discussed, including the motivation for a printed thin-film device rather than a single-CNT configuration. Two things seem certain about this field: 1) the promise of CNT-based biosensors continues to suggest they are worth ongoing pursuit, and 2) there is much work remaining towards achieving a reproducible, reliable electronic biosensing technology from CNTs.

Understanding Oxygen-Induced Reactions and Their Impact on n-Type Polymeric Mixed Conductor-Based Devices.

Electron transporting (n-type) polymeric mixed conductors are an exciting class of materials for devices with aqueous electrolyte interfaces, such as bioelectronic sensors, actuators, and soft charge storage systems. However, their charge transport performance falls short of their p-type counterparts, primarily due to electrochemical side reactions such as the oxygen reduction reaction (ORR). To mitigate ORR, a common strategy in n-type organic semiconductor design focuses on lowering the lowest unoccupied molecular orbital (LUMO) level. Despite empirical observations suggesting a correlation between deep LUMO levels, low ORR, and enhanced electrochemical cycling stability in water, this relationship lacks robust evidence. In this work, we delve into the electrochemical reactions of n-type polymeric mixed conductors with varying LUMO levels and assess the impact of ORR on charge storage performance and organic electrochemical transistor (OECT) operation. Our results reveal a limited correlation between LUMO levels and ORR currents, as well as the electrochemical operational stability of the films. While ORR currents minimally contribute to OECT channel currents under fixed biasing conditions, n-type films self-discharge rapidly at floating potentials in a capacitor-like configuration. The density functional theory analysis, complemented by X-ray photoelectron spectroscopy, underscores the critical role of backbone chemistry in controlling O2-related degradation pathways and device performance losses. These findings highlight the persistent challenge posed by ORR in n-type semiconductor design and advocate for shifting the focus toward exploring chemical moieties with limited O2 interactions to enhance operational stability and performance at n-type film/water interfaces.

Advancements in bioelectronic sensors: Strategic applications in business and healthcare management

Advancements in bioelectronic sensors: Strategic applications in business and healthcare management

Facile fabrication of foldable electrospun nanofiber electrodes for electrodes for electronic biosensing

This study presents a rapid, sensitive and selective sensor based on electrospun nanofibers on laser-patterned electrodes, in which the laser micromachining process can directly fabricate the graphene electrode device for the electronical detection of glucose molecule. The layer of graphene film was formed on the glass substrate by a screen printing technique, and then the graphene electrodes can be fabricated by the ultraviolet (UV) nanosecond laser process with the wavelength of 355 nm. Based on the controlled the laser fluence and pulses, the electrode gap of 60 μm within the device can be fabricated. The polyvinyl alcohol (PVA) and glucose oxidase (GOD) composite nanofiber with weight percentage of 8% can be used by the electrospun process with used Glutaraldehyde(GA) steam for cross linking process. After that, it is blended with the conductivity of poly(3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS), and the foldable nanofiber structures was made by electrospun process on the graphene electrode device. Finally, the electrical detection of graphene electrode device with the nanofibers at different concentrations of glucose can be measured, resulting in the linear variation is detecting the glucose concentration ranging form 0.01 to 3.12 mM. This work indicated that the low concentration and highly sensitive can be used for electronic biosensors

Transient Implantable Electronics for Postsurgery Preventive Medicine

AbstractThe field of postoperative care has seen a remarkable shift toward the utilization of electronic implantable devices, including sensors, biosensors, stimulators, and drug delivery systems, all designed with a biodegradable form factor and wireless data/power transmission capability. These technologies hold immense potential for postsurgery out‐of‐hospital monitoring during the postdischarged period, where continuous monitoring of physiological signals is lacking. Furthermore, these devices eliminate the need for secondary surgeries required for device retrieval as they can safely degraded in the body, thus enhancing patient recovery. This review delves into the latest advancements in biodegradable implantable devices, examining their application in monitoring vital signs, the innovative wireless communication and powering technologies they employ, and the biodegradable materials that enable their function. The analysis extends to evaluating the efficacy and limitations of these devices across various medical applications. Moreover, it explores future research directions, emphasizing material advancements, device miniaturization, customization, and the integration of artificial intelligence to create closed‐loop therapeutic systems. This comprehensive review underscores the transformative potential of these technologies in enhancing postoperative care and outlines the pathway for future innovations in this dynamic field.

Detection of Chemical Contaminants in Water for Irrigation Systems: A Systematic Review

Water pollution is a detrimental issue that occurs when there are bad changes in water quality parameters. It directly disrupts water usage and poses a danger to society, environment, economy, and agriculture. Water quality should be monitored to alert authorities on water pollution, so that action can be taken quickly. Improper water management pollutes rivers and lakes in Malaysia such as Klang River, Semenyih River, Kim Kim River, Slim River, and others. Various techniques are introduced to detect contaminants in water such as electronic sensors, biosensor approaches, laboratory analysis, and optical techniques. The functionality tool varies depending on the specific contaminants or parameters that are targeted, and the resources allocated. Several common contaminant types are found in polluted water including heavy metals, organic and inorganic chemicals, industrial pollutants, suspended solids, and others. The objective of the review is to study various non-optical and optical contaminant detection methods in water to identify the strengths and weaknesses of the methods. In this review, water pollution problems mainly due to the agricultural sector in several countries are discussed. Besides, conventional, and modern methods are compared in terms of parameters, complexity, and reliability. We believe that conventional methods are costly and complex, whereas modern methods are also expensive but simpler with real-time detection. Recent contaminant detection methods in water are also reviewed to study any loopholes in the latest methods. We found that the spectroscopy method based on light propagation theory is suitable and one of the promising methods for chemical contaminants detection for water quality analysis. This method offers fast analysis time, high sensitivity detection, non-invasive analysis, provides reliable data, and others. Undoubtedly, some contaminants in water can be challenging to be identified rapidly and confidently even though there are numerous tools and techniques available for water quality analysis. Thus, the review is important to compare previous methods and to improve current chemical contaminants detection analysis in terms of reliability with a minimum operating system and cost effectiveness.

Piercing the Shadows: Exploring the Influence of Signal Preprocessing on Interpreting Ultrasensitive Bioelectronic Sensor Data.

The development of ultrasensitive electronic sensors for in vitro diagnostics is essential for the reliable monitoring of asymptomatic individuals before illness proliferation or progression. These platforms are increasingly valued for their potential to enable timely diagnosis and swift prognosis of infectious or progressive diseases. Typically, the responses from these analytical tools are recorded as digital signals, with electronic data offering simpler processing compared to spectral and optical data. However, preprocessing electronic data from potentiometric biosensor arrays is still in its infancy compared to more established optical technologies. This study utilized the Single-Molecule with a Large Transistor (SiMoT) array, which has achieved a Technology Readiness Level of 5, to explore the impact of data preprocessing on electronic biosensor outcomes. A dataset consisting of plasma and cyst fluid samples from 37 patients with pancreatic precursor cyst lesions was analyzed. The findings revealed that standard signal preprocessing can produce misleading conclusions due to artifacts introduced by mathematical transformations. The study offers strategies to mitigate these effects, ensuring that data interpretation remains accurate and reflective of the underlying biochemical information in the samples.

Bridging basic science and applied diagnostics: Comprehensive viral diagnostics enabled by graphene-based electronic biosensor technology advancements

This study presents a graphene field-effect transistor (gFET) biosensor with dual detection capabilities for SARS-CoV-2: one RNA detection assay to confirm viral positivity and the other for nucleocapsid (N-)protein detection as a proxy for infectiousness of the patient. This technology can be rapidly adapted to emerging infectious diseases, making an essential tool to contain future pandemics. To detect viral RNA, the highly conserved E-gene of the virus was targeted, allowing for the determination of SARS-CoV-2 presence or absence using nasopharyngeal swab samples. For N-protein detection, specific antibodies were used. Tested on 213 clinical nasopharyngeal samples, the gFET biosensor showed good correlation with RT-PCR cycle threshold values, proving its high sensitivity in detecting SARS-CoV-2 RNA. Specificity was confirmed using 21 pre-pandemic samples positive for other respiratory viruses. The gFET biosensor had a limit of detection (LOD) for N-protein of 0.9 pM, establishing a foundation for the development of a sensitive tool for monitoring active viral infection. Results of gFET based N-protein detection corresponded to the results of virus culture in all 16 available clinical samples and thus it also proved its capability to serve as a proxy for infectivity. Overall, these findings support the potential of the gFET biosensor as a point-of-care device for rapid diagnosis of SARS-CoV-2 infection and indirect assessment of infectiousness in patients, providing additional information for clinical and public health decision-making.

A surface-functionalized whole blood-based dielectric microsensor for assessment of clot firmness in a fibrinolytic environment

Accurate assessment of fibrin clot stability can predict bleeding risk in coagulopathic conditions such as thrombocytopenia and hypofibrinogenemia. Hyperfibrinolysis — a clinical phenotype characterized by an accelerated breakdown of the fibrin clot — makes such assessments challenging by obfuscating the effect of hemostatic components including platelets or fibrinogen on clot stability. In this work, we present a biofunctionalized, microfluidic, label-free, electronic biosensor to elicit unique, specific, and differential responses from the multifactorial processes of blood coagulation and fibrinolysis ex vivo. The microsensor tracks the temporal variation in the normalized real part of the dielectric permittivity of whole blood (<10 μL) at 1 MHz as the sample coagulates within a three-dimensional, parallel-plate, capacitive sensing area. Surface biofunctionalization of the microsensor’s electrodes with physisorption of tissue factor (TF) and aprotinin permits real-time assessment of the coagulation and fibrinolytic outcomes. We show that surface coating with TF and manual addition of TF result in a similar degree of acceleration of coagulation kinetics in human whole blood samples. We also show that surface coating with aprotinin and manual addition of aprotinin yield similar results in inhibiting tissue plasminogen activator (tPA)-induced upregulated fibrinolysis in human whole blood samples. Validated through a clinically relevant, complementary assay — rotational thromboelastometry for clot viscoelasticity — we finally establish that a microsensor dual-coated with both TF and aprotinin detects the hemostatic rescue in the tPA-induced hyperfibrinolytic profile of whole blood and the hemostatic dysfunction due to concurrent platelet depletion in the blood sample, thus featuring enhanced ability in evaluating complex, combinatorial coagulopathies.

Ultrathin Indium Tin Oxide Accumulation Mode Electrolyte‐Gated Transistors for Bioelectronics

AbstractElectrolyte‐gated field effect transistors and electrochemical transistors have emerged as powerful components for bioelectronic sensors and biopotential recording devices. A set of parameters must be considered when developing devices to amplify weak electrophysiological signals. These include maximum transconductance values, cut‐off frequencies, and large on/off current ratios. Organic polymer‐based devices have recently dominated the field, especially when considering flexibility as a key factor. Oxide semiconductors may also offer these features, as well as advantages like higher mobility. Herein, flexible, ultrathin, indium tin oxide (ITO) electrolyte‐gated transistors are reported. These accumulation‐mode devices combine n‐type operation with µe = 9.5 cm2 Vs−1, high transconductance (gm = 44 mS), and on/off ratios (105) as well as optically transparent layouts. While oxides are normally considered brittle, mechanically flexible ITO layers are obtained by room temperature deposition of amorphous layers onto parylene C. This process results in low strain, producing devices that survive bending. ITO electrochemically degrades, however, with cycling. To overcome this, the surface is passivated with high dielectric constant inert capping layers of Ta2O5 or Ta2O5/AlN. This greatly improves stability while preserving low gate voltages. Based on their overall performance, ITO‐based EGFETs are promising for bioelectronics.

Microbial bioelectronic sensors for environmental monitoring

Microbial bioelectronic sensors for environmental monitoring

(Invited) Tackling Leakage, Drift, and Variation in Printed Carbon Nanotube-Based Electronic Biosensors

Semiconducting carbon nanotubes (CNTs) have been pursued for use in electronic biosensors for decades. Their all-surface molecular structure, sizeable semiconducting bandgap, and solution-phase compatibility make them highly sensitive and versatile options for transducing target bioelectrical signals. However, amid the thousands of reports on CNT-based electronic biosensors, very little attention has been given to identifying (let alone addressing) the impact of leakage current, signal drift, and device-to-device variation. This talk will present recent results focused on tackling these issues with specific emphasis on printed CNT-based biosensors. For instance, a variety of passivation strategies were studied to determine the role of leakage current for CNT transistor-based biosensors (i.e., bioFETs or ion-sensitive FETs), revealing that a bilayer epoxy/high-k dielectric stack was most effective at minimizing unwanted leakage current. The influence of signal drift will also be demonstrated, likely playing a significant role in many previous reports of CNT-based biosensors characterized by sequential concentration spikes. Finally, strategies for addressing device-to-device variation in these biosensors will be discussed, including the motivation for a printed thin-film device rather than a single-CNT configuration. Two things seem certain about this field: 1) the promise of CNT-based biosensors continues to suggest they are worth ongoing pursuit, and 2) there is much work remaining towards achieving a reproducible, reliable electronic biosensing technology from CNTs.

(Invited) Multi-Modal Solid-State Gas Sensors-Based Breath Analysis System with Convolutional Neural Network (CNN) for Early Detection of Lung Cancer

Currently, digital healthcare technologies based on Internet of Things (IOT) are emerging, and the market for digital healthcare was estimated to be 151.5 billion dollars by 2020. Among the digital healthcare technologies, disease diagnosis is attracting maximum attention. Traditional diagnostic methods, such as radiology and human biological material analysis, have limitations of long study time, high cost, radiation exposure, and pain. Therefore, non-invasive diagnostics methods, for early diagnosis of specific diseases and personal healthcare management, have attracted attention.Breath sensors are one of the promising candidates for the realization of non-invasive diagnosis owing to their ease of use, safety, and cost effectiveness. The exhaled breath analysis technique holds great promise as a non-invasive method for diagnosing lung cancer. In the breath of lung cancer patients, various volatile organic compounds (VOCs) markers are generated during metabolic processes. Analyzing these VOCs markers presents a compelling avenue for early and non-invasive lung cancer diagnosis. Solid state gas sensors capable of measuring specific VOCs are currently being researched and utilized as commercial gas sensors for this purpose. However, the concentration of lung cancer VOCs markers in exhaled breath is commonly very low, and individual commercial gas sensors often lack the necessary sensitivity and selectivity to accurately diagnose lung cancer. In this study, we propose a multimodal solid state electronic biosensor system designed to differentiate lung cancer VOCs characteristics among multiple VOCs, enabling exhalation-based lung cancer diagnosis. Initially, we developed multimodal biosensors using more than 20 gas sensors, consisting of metal oxide semiconductor sensors, electrochemical sensors, photoionized detectors, metalorganic frame sensors and so on. And each exhibiting varying sensitivity profiles for complex gas mixtures. Additionally, we designed a classification algorithm based on convolutional neural networks (CNN) and multi-layered perceptron (MLP) to distinguish between lung cancer patients and healthy individuals using the output from these diverse multimodal gas sensors. To evaluate the system's performance, we collected exhaled air samples from 74 lung cancer patients and 107 normal subjects, conducting clinical trials with our developed system. We did model evaluation with confusion matrix and ROC curve. The results of these tests confirmed that our system achieved a high predictive accuracy of over 95% in classifying lung cancer patients. The simplicity of the sensor configuration in our developed system makes it suitable for large-scale screening tests to identify potential candidates for precise lung cancer diagnosis. This technology has the potential to contribute to reduced national welfare costs and improved patient survival rates through early diagnosis.

Transforming Renal Diagnosis: Graphene‐Enhanced Lab‐On‐a‐Chip for Multiplexed Kidney Biomarker Detection in Capillary Blood

AbstractChronic kidney disease (CKD) is a significant global health concern, impacting over 10% of the world population. Despite advances in home‐based treatments, CKD diagnosis and monitoring remain centralized in large laboratories. This work reports on the development of a Graphene‐based Lab‐On‐a‐Chip (G‐LOC) for the self‐testing of multiple renal function biomarkers in capillary blood. G‐LOC integrates bioelectronic sensors with a 3D‐printed microfluidic system that enables the multiplex quantification of urea, potassium, sodium, and chloride, from one drop of blood. The potentials of three graphene sensors modified with ion‐selective membranes and enzymes are simultaneously measured. The analytical performance of the test is evaluated in terms of linearity, accuracy, and coefficient of variability (CV). Accuracy values higher than 98.7%, and CV values lower than 10.8% are obtained for all the biomarkers. Correlation and Bland–Altman plots show good correlation (slopes in the range of 0.94–1.15) and high agreement of G‐LOC with a reference method. It is also demonstrated that the test can correctly differentiate biomarker levels normally obtained for healthy people, early‐stage CKD, and end‐stage CKD. Finally, user experience is studied with a group of untrained volunteers who highlight the simple usability of the test and its suitability for at‐home diagnostics.