Uric Acid Biosensor Research Articles

Novel cobalt-based aerogels for uric acid detection in fluids at physiological pH

A sensor for uric acid (UA) based on the urate oxidase enzyme (UOx) immobilized in novel Co-based aerogels with transition metals synthesized by the sol-gel method was developed and evaluated. The Co-based aerogels: Co, Ni-Co and Pd-Co were physicochemically characterized by XRD and HR-TEM. The surface area values of 53, 57 and 66 m2 g-1 were determined for Co, Ni-Co and Pd-Co, respectively by N2 adsorption-desorption technique. Co-based aerogels were mixed by cross-linking with UOx enzymes and electrochemically characterized in buffers at pH 7.4 and 5.6 (pH values reported for biological fluids such as blood and sweat) in the presence of different uric acid concentrations. Co-based aerogels with UOx showed improved performance as a uric acid biosensor compared to using the enzyme alone. At a pH of 7.4, a higher sensitivity of 11 μA μM−1 was obtained with Pd-Co/UOx, 1.6 times higher than with UOx. At a pH value of 5.6, the highest sensitivity is achieved with Ni-Co/UOx. Stability and selectivity tests were performed in the presence of biological interferents without significant changes in the sensor. These results indicate a pleasing synergistic activity between Co-based aerogels and the enzyme.

ZnS and Reduced Graphene Oxide Nanocomposite-Based Non-Enzymatic Biosensor for the Photoelectrochemical Detection of Uric Acid.

In this work, we report a study of a zinc sulfide (ZnS) nanocrystal and reduced graphene oxide (RGO) nanocomposite-based non-enzymatic uric acid biosensor. ZnS nanocrystals with different morphologies were synthesized through a hydrothermal method, and both pure nanocrystals and related ZnS/RGO were characterized with SEM, XRD and an absorption spectrum and resistance test. It was found that compared to ZnS nanoparticles, the ZnS nanoflakes had stronger UV light absorption ability at the wavelength of 280 nm of UV light. The RGO significantly enhanced the electron transfer efficiency of the ZnS nanoflakes, which further led to a better photoelectrochemical property of the ZnS/RGO nanocomposites. The ZnS nanoflake/RGO nanocomposite-based biosensor showed an excellent uric acid detecting sensitivity of 534.5 μA·cm-2·mM-1 in the linear range of 0.01 to 2 mM and a detection limit of 0.048 μM. These results will help to improve non-enzymatic biosensor properties for the rapid and accurate clinical detection of uric acid.

Graphene oxide-zinc oxide nanocomposite modified disposable electrodes for detection of uric acid in fetal bovine serum

Uric acid (UA) is the end product of purine metabolism, which is involved in many physiological processes in humans. This compound is produced daily in the human body and the excess is excreted in urine. For various reasons, uric acid in human serum that is lower or higher than the reference range causes some diseases such as liver diseases, nephritis, multiple sclerosis and diabetes. Hence, determination of UA at trace levels is very crucial. Here, a pencil graphite electrode (PGE) modified with graphene oxide-zinc oxide (GO-ZnO) nanocomposite was used to develop an electrochemical biosensor (GO-ZnO/PGE) for UA detection. The prepared GO-ZnO modified electrodes was characterized by scanning electron microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDX), Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). It was revealed that the existence of ZnO in the GO-ZnO/PGE largely enhanced the surface area and increased its sensitivity for electrochemical sensing of analyte. The uric acid biosensor exhibited voltammetric peaks in the differential pulse voltammetry (DPV) measurements, allowing electrochemical detection of UA. The detection limit of UA was found to be 2.56 μM in buffer medium in the range of 10–100 µM UA. The detection limit of UA was found to be 4.76 μM in 1:1000 diluted FBS medium in the range of 10–100 µM of UA. The GO-ZnO/PGE provided the results in good reproducubility based on electrochemical measuruments while detecting UA. Furthermore, selectivity tests were also performed in FBS medium containing possible interferents such as ascorbic acid (AA) and Glucose (Glu), demonstrating the applicability of GO-ZnO modified electrodes. Sensitivity was calculated for phosphate-buffered saline (PBS) and fetal bovine serum (FBS) mediums and found to be 0.22 and 0.47 μA μg−1mL cm−2, respectively, which validates the good sensitivity of the GO-ZnO/PGE electrodes.

Flow injection amperometric uric acid biosensor based on AuNPs–GO–CS porous composite cryogel coated on PB–PEDOT:PSS modified screen-printed carbon electrode

An enzymatic amperometric uric acid (UA) biosensor was successfully developed by modifying a screen-printed carbon electrode (SPCE) with Prussian blue-poly(3,4-ethylene dioxythiophene) polystyrene sulfonate composite (PB-PEDOT:PSS). The modified SPCE was coated with gold nanoparticles-graphene oxide-chitosan composite cryogel (AuNPs–GO–CS cry). Uricase (UOx) was directly immobilized via chemisorption on AuNPs. The nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. The electrochemical characterization of the modified electrode was performed by cyclic voltammetry and electrochemical impedance spectroscopy. UA was determined using amperometric detection based on the reduction current of PB which was correlated with the amount of H2O2 produced during the enzymatic reaction. Under optimal conditions, the fabricated UA biosensor in a flow injection analysis (FIA) system produced a linear range from 5.0 to 300 μmol L−1 with a detection limit of 1.88 μmol L−1. The proposed sensor was stable for up to 221 cycles of detection and analysis was rapid (2 min), with good reproducibility (RSDs < 2.90 %, n = 6), negligible interferences, and recoveries from 94.0 ± 3.9 to 101.1 ± 2.6 %. The results of UA detection in blood plasma were in agreement with the enzymatic colorimetric method (P > 0.05).

Bioinspired mp20 mimicking uricase in ZIF-8: Metal ion dependent for controllable activity

Mini protein mimicking uricase (mp20) has shown significant potential as a replacement for natural enzymes in the development of uric acid biosensors. However, the design of mp20 has resulted to an inactive form of peptide, causing of loss their catalytic activity. Herein, this paper delineates the impact of various metal cofactors on the catalytic activity of mp20. The metal ion-binding site prediction and docking (MIB) web server was employed to identify the metal ion binding sites and their affinities towards mp20 residues. Among the tested metal ions, Cu2+ displayed the highest docking score, indicating its preference for interaction with Thr16 and Asp17 residues of mp20. To assess the catalytic activity of mp20 in the presence of metal ions, uric acid assays was monitored using a colorimetric method. The presence of Cu2+ in the assays promotes the activation of mp20, resulting in a color change based on quinoid production. Furthermore, the encapsulation of the mp20 within zeolitic imidazolate framework-8 (ZIF-8) notably improved the stability of the biomolecule. In comparison to the naked mp20, the encapsulated ZIFs biocomposite (mp20@ZIF-8) demonstrates superior stability, selectivity and sensitivity. ZIF’s porous shells provides excellent protection, broad detection (3–100 μM) with a low limit (4.4 μM), and optimal function across pH (3.4–11.4) and temperature (20–100°C) ranges. Cost-effective and stable mp20@ZIF-8 surpasses native uricase, marking a significant biosensor technology breakthrough. This integration of metal cofactor optimization and robust encapsulation sets new standards for biosensing applications.

A conducting polymer-based array with multiplex sensing and drug delivery capabilities for smart bandages

Effective individual wound management, particularly in cases of prolonged healing and increased infection vulnerability, has prompted the development of wound theranostics, combining real-time diagnostic assessment and on-demand treatment. Here, we present a multifunctional conducting polymer-based smart theranostic bandage that integrates pH sensing, pH-compensated uric acid (UA) biosensing, and on-demand antibiotic release using different conducting polymers, each leveraging their advantageous intrinsic properties. Specifically, the polyaniline-based pH sensor operates reversibly across a pH range of 4–10, while the functionalized poly(3,4-ethylenedioxythiophene)-based UA biosensor exhibits a linear response up to 0.9 mM UA. Simultaneous detection of pH and UA allows accurate UA determination via pH compensation. Upon detecting abnormal pH/UA levels, the polypyrrole-based drug carrier releases ciprofloxacin via 0.6 V electrical stimulation, successfully inhibiting bacterial growth in vitro. The array is assembled as a 3D patch, connected to a flexible printed circuit board, and embedded in a wound bandage, offering potential for remote wound monitoring, targeted treatment, and wireless wound management.

Convenient in situ self-assembled formation of dual-functional Ag/MXene nanozymes for efficient chemiluminescence sensing.

MXenes are attracting increasing interest as a low-cost carrier for the development of nanozymes with enhanced peroxidase or oxidase-like activity. In this work, silver nanoparticles (AgNPs) were synthesized and loaded on Ti3C2 MXene nanosheets (denoted as Ag/MXene) by a simple method, using MXene as a support and reducing agent. The synthesized Ag/MXene composites exhibited satisfactory stability and the peroxidase activity was higher than that of the single components. In the presence of luminol and hydrogen peroxide (H2O2), Ag/MXene could catalyze H2O2 to produce reactive oxygen species (ROS) and act on luminol to generate strong chemiluminescent (CL) signals. Free radical scavenging experiments and electron paramagnetic resonance spectroscopy confirmed the production of these radicals. In this regard, we fabricated a facile biosensor for glutathione (GSH) and uric acid (UA) detection and the results showed good linear relationship between GSH and UA. The linear ranges of GSH and UA were 50 nM to 20 μM and 1 μM to 35 μM, respectively, with low detection limits of 0.83 nM and 0.37 μM. The sensor platform established in this study provides the possibility for developing MXene biosensors with high sensitivity and performance, and lays the solid foundation for expanding the application of MXene in biosensors.

Wearable Biosensor Utilizing Chitosan Biopolymer for Uric Acid Monitoring

A wearable biosensor was specifically engineered to measure uric acid, a biomarker present at wound sites. This biosensor, fabricated as a disposable and wearable device, was seamlessly integrated onto a polyethylene terephthalate (PET) substrate by utilizing carbon and silver conductive paste as the electrodes. The enzyme uricase was immobilized onto the working electrode by utilizing chitosan, a biocompatible material, to create this biosensor. Notably, the uric acid biosensor fabricated with chitosan showcased exceptional performance metrics, including remarkable output current values and impeccable stability. These findings suggest the prospective utilization of chitosan-based uric acid biosensors for the accurate measurement of uric acid on human skin in future applications.

Modeling of photofunctional transition metals (Mn, Re, Ir) complexes towards the effective detection of uric acid (UA) as biomarker for kidney dysfunction

The potential of isatinic quinolyl Schiff bases transition metal complexes as electronic biosensors for detecting kidney dysfunction biomarker (uric acid) denoted as UA was investigated from first principles computations. The adsorption of UA onto the metal centres of Ir, Mn and Re complexes of (Z)-5-bromo-3-(quinolin-8-ylimino)indolin-2-one and (Z)-5-nitro-3-(quinolin-8-ylimino)indolin-2-one, designated as L1 and L2 were studied extensively. Uric acid has been considered an essential biomarker for oxidative stress, human arthritis, cardiomyopathy, and hyperuricemia. Biomarkers perform a pivotal role in the successful diagnosis and treatment of several diseases. Dispersion-corrected DFT calculations were performed, and the results evinced that the modelled transition metal complexes are promising candidates for UA detection. It was found that UA is chemisorbed by coordinating with the metal centers and ligands at a 3.873 Å distance on average with the adsorption enthalpies being −37.11 kcal/mol, –32.95 kcal/mol, and −21.44 for UA@L2Mn, UA@L2Re and UA@L2Ir complexes respectively. While the computed adsorption enthalpies for L1 complexes were found to be −24.47 kcal/mol. –22.11 kcal/mol and –22.19 kcal/mol respectively for UA@L1Ir, UA@L1Mn and UA@L1Re complexes showing that the L2 complexes acted as better sensors for UA. The sensitivity of UA by the metal complexes was influenced by the binding conformation of UA and the adsorption sites of the ligands. Overall, the metal complexes demonstrated high sensitivity with high values of work function up to 7.13 eV being recorded and hence making suitable substrates for work-function based sensors. Good stability and excellent conductivity even with the adsorption of UA was maintained and the desorption test-based on the transition state theory was considered and the complexes showed promising results for practical implementation as UA biosensors.

Improving Interface Matching in MOF-on-MOF S-Scheme Heterojunction through π-π Conjugation for Boosting Photoelectric Response.

Accelerating the migration of interfacial carriers in a heterojunction is of paramount importance for driving high-performance photoelectric responses. However, the inferior contact area and large resistance at the interface limit the eventual photoelectric performance. Herein, we fabricated an S-scheme heterojunction involving a 2D/2D dual-metalloporphyrin metal-organic framework with metal-center-regulated CuTCPP(Cu)/CuTCPP(Fe) through electrostatic self-assembly. The ultrathin nanosheet-like architectures reduce the carrier migration distance, while the similar porphyrin backbones promote reasonable interface matching through π-π conjugation, thereby inhibiting the recombination of photogenerated carriers. Furthermore, the metal-center-regulated S-scheme band alignments create a giant built-in electric field, which provides a huge driving force for efficient carrier separation and migration. Coupling with the biomimetic catalytic activity of CuTCPP(Fe), the resultant heterojunction was utilized to construct photoelectrochemical uric acid biosensors. This work provides a general strategy to enhance photoelectric responses by engineering the interfacial structure of heterojunctions.

A Potentiometric Uric Acid Biosensor Integrated With Temperature Correction Readout Circuit on Flexible PCB

This study presents the enzymatic potentiometric uric acid sensor with a temperature correction circuit, sensor set readout, and integration on a flexible printed circuit board (FPCB). Coupled with the uric acid sensor calibrated by the temperature sensor, the readout voltage can respond directly to the sensed uric acid value. Complete circuits are surface mounted on commercial electroless nickel immersion gold FPCBs. Such a miniaturized potentiometric sensor provides the shortest signal path to reduce measurement errors and noise interference. The voltage-time measurement system used to measure the sensing characteristics of the potentiometric uric acid sensor is also analyzed. In addition to high linearity and repeatability, the sensor has an average sensitivity of 19.65 mV/(mg/dL), and the error caused by temperature changes is reduced by 81% after temperature correction.

Self-Assembled Monolayers on Screen-Printed Gold Electrodes for Uricase Enzyme Covalent Immobilization

This work reports the development of an electrochemical biosensor for uric acid (UA), based on covalent immobilization of uricase (Uox) on cysteamine self-assembled monolayers (SAM). The monolayers were prepared over screen-printed gold electrode (AuSPE) modified with Au nanostructures for covalent linkage through EDC-NHS. The modified AuSPE was characterized by Scanning Electron Microscope (SEM) and Cyclic Voltammetry (CV). The results verified the cysteamine SAM formation, and the improved electrochemical performance of the working surface. The AuSPE/SAM/Uox biosensor presented a linear range of 0.84 – 16.81 mg/dL (50-1000 µM), a sensibility of 9.1423 µA/(mg/dL)cm2, and a limit of detection (LOD) of 0.0700 mg/dL. The biosensor did not present a response due to ascorbic acid (AA), verifying the selectivity of the assembly only to UA oxidation. The AuSPE/SAM/Uox showed a promising performance as a reliable, simple and fast detection tool for UA.

Transition metal complex-incorporated polyaniline as a platform for an enzymatic uric acid electrochemical sensor.

Uric acid (UA) is the primary waste product from purine metabolism in humans. Excessive UA levels in the body will accumulate in joints and form crystals that cause a wide range of health problems. An enzymatic electrochemical biosensor for UA based on the transition metal complex-incorporated polyaniline PANI-RC functionalized with both urate oxidase (UOx) as a specific bioreceptor and horseradish peroxidase (HRP) as a signal enhancer was developed. The transition metal complex being used herein is the commonly used redox couple (RC) in electrochemical biosensors, [Fe(CN)6]3-/4-, which plays the pivotal role of electron acceptors. This PANI-RC platform then becomes a conducive environment not only for enzyme immobilization but also for signal transfer improvement. The synergistic combination of HRP near UOx and RC anchored on the backbone of PANI helps in electron transfer from the enzymatic reaction to the current collector. The resulting PANI-RC-based UA sensor demonstrates high sensitivity with a detection limit of 11.4 μM, wide linear range, good stability, and excellent selectivity even in the presence of the most problematic interference in UA assays (e.g., ascorbic acid and urea). The recovery tests using artificial biofluid-spiked UA samples also showed promising results for practical usage of the PANI-RC-based UA sensor.

An ultra-sensitive uric acid second generation biosensor based on chemical immobilization of uricase on functionalized multiwall carbon nanotube grafted palm oil fiber in the presence of a ferrocene mediator.

In this work, palm oil fiber (POF) grafted functionalized multiwall carbon nanotube (FMWCNT) decorated ferrocene (Fc) has been drop coated on a platinum electrode (Pt), in which uricase (UOx) has been chemically immobilized for sensitive and selective biosensing of uric acid (UA). Through the use of EDC/NHS, a stable bioelectrode (UOx/Fc/FMWCNT-POF/Pt) was obtained and characterized by FTIR/ATRIR, XRD, Raman, EA/EDX, TGA, SEM, TEM, CV, EIS, CA, and DPV. Results from DPV showed the rapid response of the developed bioelectrode towards UA (0.185 V) with high sensitivity (41.14 μA mM-1) and good limit of detection (19 μM) in the linear range 10-1000 μM. The low value of Michaelis-Menten constant (km = 31.364 μM) shows high affinity of the UA towards the enzyme at the electrode surface. The developed biosensor demonstrates good reproducibility, repeatability, and stability with a deviation of less than 2.5%, and was successfully applied for human blood sample analysis. The CA study revealed a fast response time (2 s) of the sensor. The work has pioneered a new addition to the class of tailorable chemical species for biosensor development and proven to be a promising new tool for point of care testing (POCT) applications.

A Graphene/Prussian Blue/Rhodium Printed Biosensor for Detecting Uric Acid and Its Clinical Evaluation

Uric acid is produced via the purine metabolism pathway, and an abnormal level of uric acid could lead to serious diseases and complications, such as gout, renal, and cardiovascular diseases. A rapid, convenient, and accurate detection of uric acid is highly desired for healthcare applications. Here, we report a screen-printed amperometric biosensor for uric acid based on a composite ink consisting of graphene, Prussian blue (PB), and rhodium (Rh)/carbon catalyst. The working electrode is printed by a graphene/PB ink and an Rh/carbon (Rh/C) ink sequentially with drying in between. The linear detection range for uric acid is 0.04–0.8 mM with a response time of 30 s and a detection limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.55 ~\mu \text{M}$ </tex-math></inline-formula> . The biosensor could be stored in a refrigerator at 4 °C for 80 days without a significant decrease in response. Furthermore, compared to the detection results from the clinical standard method, the relative error of the biosensor is within 20% for detecting uric acid in human blood samples. It is anticipated that this work could advance exciting fundamental studies for uric acid-sensing devices, as well as the clinical applications for the detection of uric acid.

Fabrication of Electrochemical Biosensor Using Zinc Oxide Nanoflowers for the Detection of Uric Acid

A label-free electrochemical biosensor has been developed using zinc oxide nanoflowers (ZnONFs) for the detection of uric acid concentration in human blood serum. ZnONFs have been synthesized by a hydrothermal process and characterized with several techniques such as ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR) studies, X-ray diffraction (XRD) study, Raman spectroscopy, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) and electrochemical analyzer to confirm the formation of nanoflowers and fabrication of electrode and bio-electrodes for uric acid detection. Zinc Oxide nanoflowers have been deposited onto indium–tin oxide (ITO) substrate through electrophoretic deposition technique, and the biosensor has been fabricated by immobilizing urate oxidase (UOx) enzyme onto ZnONFs/ITO electrode surfaces. Further, electrochemical studies have been performed with immobilized UOx/ZnONFs/ITO bio-electrode as a function of uric acid concentrations. It has been found that the fabricated uric acid biosensor shows a high sensitivity (10.38 μA/mM/cm2) and a limit of detection of 0.13 mM in the range of 0.005 to 1.0 mM. This study demonstrates the potential use of ZnONFs for the construction of sensitive biosensors for uric acid detection.

Uric acid and creatinine biosensors with enhanced room-temperature storage stability by a multilayer enzyme matrix

Uric acid and creatinine are essential biomarkers for many diseases, such as gout, hyperuricemia, kidney diseases and heart diseases. Electrochemical biosensors are promising candidates for detecting uric acid and creatinine. However, the sensors always suffer from low stability that would limit their practical applications. In this work, we report a new multilayer enzyme matrix to enhance the room-temperature storage stabilities of uric acid and creatinine biosensors significantly. The enzymes are first dropped on the electrode surface directly, then a layer of glutaraldehyde was deposited on the surface of the enzyme layer, and after that, another layer of a polyvinyl alcohol (PVA)/poly(ethylene glycol) (PEG) composite was further placed on the surface of the glutaraldehyde layer, with drying in between. The stabilities of uric acid and creatinine biosensors were enhanced significantly, and the sensors can maintain highly stable sensing performance for over 4 months with a storage at room temperature. It is anticipated that this work could open new avenues for the practical applications of the uric acid and creatinine biosensors.

Electrochemical enzyme-based blood uric acid biosensor: new insight into the enzyme immobilization on the surface of electrode via poly-histidine tag.

In a new approach, we considered the special affinity between Ni and poly-histidine tags of recombinant urate oxidase to utilize Ni-MOF for immobilizing the enzyme. In this study, a carbon paste electrode (CPE) was modified by histidine-tailed urate oxidase (H-UOX) and nickel-metal-organic framework (Ni-MOF) to construct H-UOX/Ni-MOF/CPE, which is a rapid, sensitive, and simple electrochemical biosensor for UA detection. The use of carboxy-terminal histidine-tailed urate oxidase in the construction of the electrode allows the urate oxidase enzyme to be positioned correctly in the electrode. This, in turn, enhances the efficiency of the biosensor. Characterization was carried out by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and field emission scanning electron microscopy (FE-SEM). At optimum conditions, the biosensor provided a short response time, linear response within 0.3-10µM and 10-140µM for UA with a detection limit of 0.084µM, repeatability of 3.06%, and reproducibility of 4.9%. Furthermore, the biosensor revealed acceptable stability and selectivity of UA detection in the presence of the commonly coexisted ascorbic acid, dopamine, L-cysteine, urea, and glucose. The detection potential was at 0.4V vs. Ag/AgCl.

A Novel Uric Acid Biosensor Based on Regular Prussian Blue Nanocrystal/ Upright Graphene Oxide Array Nanocomposites

Background: Uric acid (UA) is an important metabolic intermediate of the human body. Abnormally high levels of UA will cause diseases. However, UA monitoring with commercial products relies on invasive blood collection, which not only causes pain in patients but also risks bacterial infections and skin irritation. In recent years, new models of noninvasive detection through body surface penetration have raised higher expectations for the sensitivity of uric acid detection, and rapid, accurate and highly sensitive UA sensors will become powerful tools for the diagnosis of UA-related diseases. Objective: This study aimed to identify the differences in catalytic efficiency between regular PB from spray crystallization (RPB) and irregular PB from electrodeposition (EDPB), which is used for fabricate a high sensitive uric acid sensor. Method: Regular Prussian blue nanocrystals (RPB) were grown on graphene oxide flakes (GO), on the surface of a custom screen-printed carbon electrode (SPCE), using a spray method assisted by a constant magnetic field (CMF). After immobilizing uricase, the uric acid biosensor Uricase/RPB/CMF-GO/SPCE was obtained. Result: The detection range of the sensor response to UA was 0.005~2.525 mM, and the detection limit was as low as 3.6 μM. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results showed that compared to amorphous electrodeposited Prussian blue (EDPB), RPB more favorably accelerated electron transport. Conclusion: This novel uric acid biosensor exhibits high sensitivity over a wide concentration range, strong anti-interference ability, and good stability and reproducibility. Thus, it has good application prospects for determining uric acid in physiological samples.

Salivary uric acid sensor using the fordable “Finger‐Powered” microfluidic device

AbstractHere, we report a novel biosensing system using a finger‐powered microfluidic device, which is suitable for daily self‐testing of uric acid in saliva. To realize the rapid determination of salivary uric acid, the biosensing system measures directly from the paper‐based saliva sampling device. The microfluidic device has the diaphragm pump, the reagent reservoir, and the reaction cell in which the electrochemical uric acid biosensor is embedded. Once the microfluidic chip has been folded, the finger‐powered microfluidic device prepares the reagent containing the saliva, which is ready to measure. A wireless potentiostat for electrochemical measurement of uric acid with the biosensor was also developed. Combining these elements together, the whole process from saliva sampling to determination was completed in less than a minute (Sensitivity: 0.03 nA/μM). The measurement results were also consistent with that measured using a commercially available uric acid determination kit. Hence, our method is expected to have the potential to enhance the use of biochemical information in the field of healthcare IoT.