Mesoporous Silica Nanoparticles-Enhanced Microarray Technology for Highly Sensitive Simultaneous Detection of Multiplex Foodborne Pathogens.

Ensuring food safety is paramount for the food industry and global health concerns. In this study, we have developed a method for the detection of prevalent foodborne pathogenic bacteria, including Escherichia coli, Salmonella spp., Listeria spp., Shigella spp., Campylobacter spp., Clostridium spp., and Vibrio spp., utilizing antibody-aptamer arrays. To enhance the fluorescence signals on the microarray, the mesoporous silica nanoparticles (MSNs) conjugated with fluorescein, streptavidin, and seven detection antibodies-biotin were employed, forming fluorescein doped mesoporous silica nanoparticles conjugated with detection antibodies (MSNs-Flu-SA-Abs) complexes. The array pattern was designed for easy readability and enabled the simultaneous detection of all seven foodborne pathogens, referred to as the 7FP-biochip. Following the optimization of MSNs-Flu-SA-Abs complexes attachment and enhancement of the detection signal in fluorescent immunoassays, a high level of sensitivity was achieved. The detection limits for the seven pathogens in both buffer and food samples were 102 CFU/mL through visual screening, with fluorescent intensity quantification achieving levels as low as 20-34 CFU/g were achieved on the antibody-aptamer arrays. Our antibody-aptamer array offers several advantages, including significantly reduced nonspecific binding with no cross-reaction between bacteria. Importantly, our platform detection exhibited no cross-reactivity among the tested bacteria in this study. The multiplex detection of foodborne pathogens in canned tuna samples with spiked bacteria was successfully demonstrated in real food measurements. In conclusion, our study presents a promising method for detecting multiple foodborne pathogens simultaneously. With its high sensitivity and specificity, the developed antibody-aptamer array holds great potential for enhancing food safety and public health.

Portable Paper-Based Immunoassay Combined with Smartphone Application for Colorimetric and Quantitative Detection of Dengue NS1 Antigen.

Dengue virus (DENV) infection, which is transmitted by Aedes mosquitoes, is a major public health concern in tropical and subtropical countries. With an annual incidence of approximately 10 million cases and 20,000-25,000 deaths, particularly among children, there is an urgent need for practical diagnostic tools. The presence of dengue non-structural protein 1 (NS1) during early infection has been linked to cytokine release, vascular leakage, and endothelial dysfunction, making it a potential marker for severe dengue. Paper-based immunoassays such as lateral flow assays (LFAs) and microfluidic paper-based analytical devices (PADs) have gained popularity as diagnostic tests due to their simplicity, rapidity, inexpensiveness, specificity, and ease of interpretation. However, conventional paper-based immunoassays for dengue NS1 detection typically rely on visual inspection, yielding only qualitative results. To address this limitation and enhance sensitivity, we proposed a highly portable NS1 dengue detection assay on a Paper-based Analytical Device (PAD), namely, DEN-NS1-PAD, that integrates a smartphone application as a colorimetric and quantitative reader. The development system enables direct quantification of NS1 concentrations in clinical samples. Serum and blood samples obtained from patients were utilized to demonstrate the system prototype performance. The results were obtained immediately and can be employed for clinical assessment, both in well-equipped healthcare facilities and resource-limited settings. This innovative combination of a paper-based immunoassay with a smartphone application offers a promising approach for enhanced detection and quantification of dengue NS1 antigen. By augmenting sensitivity beyond the capabilities of the naked eye, this system holds great potential for improving clinical decision-making in dengue management, particularly in remote or underserved areas.

Detection of DNA using gold nanoparticle-coated silica nanoparticles.

We report a sensitive lateral flow assay (LFA) in which the assay colour change originated from reporter labels constructed from silica spheres (radius = 450 nm) coated with approximately 3.9 × 103 gold nanoparticles (radius = 8.5 nm). These reporter labels were modified with DNA and deposited in the conjugation area of an LFA device assembled on wax-patterned Fusion 5 paper. Test and control zones of the device were pre-loaded with capture probe formed by avidin-coated mesoporous silica nanoparticles attached with biotin-tagged DNA sequences. Proof-of-concept was demonstrated by the detection of a partial sequence of the actin gene of Colletotrichum truncatum. The DNA target could be detected with an LOD of 46 pM, which was 5 times lower than a comparative assay using gold nanoparticles alone. The assay showed good selectivity against the Colletotrichum species C. scovillei and C. gloeosporioides, as well as against DNA from the fungal genera Aspergillus niger and Alternaria alternata. There was negligible change in sensor response over storage for one month at room temperature. The LFA was used to detect PCR products following extraction from mycelium.

Bio-Electroanalysis Performance of Heme Redox-Center for π-π Interaction Bonding of a Methylene Blue-Graphene Modified Electrode.

Hemeprotein detection has motivated extensive research on the direct reaction of a heme molecule and a redox dye. The present study used methylene blue as both donor and acceptor for a redox reaction. First, the solid phases of methylene blue (MB) and graphene (GP) formed a π-π interaction bond at the aromatic rings. The conductivity of GP was better than that of carbon in a carbon electrode (CE). Then, the working CE was modified using strong adsorption of MB/GP on the electrode surface. The surface of the electrode was investigated using a modified and an unmodified electrode. The electrode's properties were studied using voltammograms of redox couple K3[Fe(CN)6]3-/4-. Its reaction was used to find the active area of the modified electrode, which was 1.76 times bigger than that of the unmodified electrode. The surface coverage values of the modified and unmodified electrodes were 8.17 × 10-6 and 1.53 × 10-5 mol/cm2, respectively. This research also studied the application of hemeprotein detection. Hemoglobin (Hb), myoglobin (Mb), and cytochrome c (Cyt. C) were studied by the reaction of Fe (III/II) at the heme-redox center. The electrocatalytic reaction between MB/GP and hemeproteins produced an anodic peak at 0.35 V for Hb, Mb, and Cyt. C. This nanohybrid film enhanced electron transfer between protein molecules and the modified carbon electrode. The amperometric measurements show that the limit of detection was 0.2 µM, 0.3 µM, and 0.1 µM for Hb, Mb, and Cyt. C, respectively. The measurement spanned a linear range of 0.2 µM to 5 µM, 0.3 µM to 5 µM, and 0.1 µM to 0.7 µM for Hb, Mb, and Cyt. C, respectively. Hb showed the lowest sensitivity compared with Mb and Cyt. C due to the role of steric hindrance in the hemeprotein specificity structure. This study offers a simple and efficient fabrication platform for electrochemical sensors for hemeproteins. When compared to other complex immobilization processes, the fabrication method for this sensor has many benefits, including no need for special chemicals and easy preparation and electrode modification-both of which are crucial for the development of electrochemical sensing devices.

Challenges of Emerging Wearable Sensors for Remote Monitoring toward Telemedicine Healthcare.

Digitized telemedicine tools with the Internet of Things (IoT) started advancing into our daily lives and have been incorporated with commercial wearable gadgets for noninvasive remote health monitoring. The newly established tools have been steered toward a new era of decentralized healthcare. The advancement of a telemedicine wearable monitoring system has attracted enormous interest in the multimodal big data acquisition of real-time physiological and biochemical information via noninvasive methods for any health-related industries. The expectation of telemedicine wearable creation has been focused on early diagnosis of multiple diseases and minimizing the cost of high-tech and invasive treatments. However, only limited progress has been directed toward the development of telemedicine wearable sensors. This Perspective addresses the advancement of these wearable sensors that encounter multiple challenges on the forefront and technological gaps hampering the realization of health monitoring at molecular levels related to smart materials mostly limited to single use, issues of selectivity to analytes, low sensitivity to targets, miniaturization, and lack of artificial intelligence to perform multiple tasks and secure big data transfer. Sensor stability with minimized signal drift, on-body sensor reusability, and long-term continuous health monitoring provides key analytical challenges. This Perspective also focuses on, promotes, and highlights wearable sensors with a distinct capability to interconnect with telemedicine healthcare for physical sensing and multiplex sensing at deeper levels. Moreover, it points out some critical challenges in different material aspects and promotes what it will take to advance the current state-of-art wearable sensors for telemedicine healthcare. Ultimately, this Perspective is to draw attention to some potential blind spots of wearable technology development and to inspire further development of this integrated technology in mitigating multimorbidity in aging societies through health monitoring at molecular levels to identify signs of diseases.

Label-free ultra-sensitive colorimetric detection of hepatitis E virus based on oxidase-like activity of MnO2 nanosheets.

Hepatitis E virus (HEV) is an evolving infectious entity that causes viral hepatitis infections worldwide. Current routine methods of identifying and diagnosing HEV are someway laborious and costly. Based on the biomimicking oxidase-like activity of MnO2 nanosheets, we designed a label-free, highly sensitive colorimetric sensing technique for HEV detection. The prepared MnO2 catalyst displays intrinsic biomimicking oxidase-like catalytic activity and efficiently oxidizes the 3,3',5,5'-tetramethylbenzidine (TMB) substrate from colorless to blue colored oxidized TMB (oxTMB) product which can be measured at 652 nm by UV-visible spectrum. When the HEV-DNA was added, DNA adsorbed easily on MnO2 surface through physical adsorption and electrostatic interaction which hinders the oxidase-like catalytic activity of MnO2. Upon the introduction of target, the HEV target DNA binds with its complementary ssDNA on the surface of MnO2, the hybridized DNA releases from the surface of MnO2, which leads to recovery of oxidase-like catalytic activity of MnO2. This strategy was applied to construct a colorimetric technique for HEV detection. The approach works in the linear range of 1 fM-100 nM DNA concentration with the limit of detection (LOD) of 3.26 fM (S/N = 3) and quantitative limit (LOQ) of 36.08 fM. The TMB-MnO2 platform was highly selective for HEV target DNA detection when compared with potential interferences. Result of serum sample analysis demonstrates that this sensing system can be used for clinical diagnostic applications.

Hydrothermal synthesis of carbon quantum dots with size tunability via heterogeneous nucleation.

Hydrothermal synthesis has been extensively utilized for fabricating carbon quantum dots (CQDs). Generally, the average sizes of the CQDs are controlled by using specific precursor concentrations, processing temperatures, and reaction times. In our study, the average size of CQDs can simply be controlled by using a different filling volume of sucrose solution in the hydrothermal reactor while keeping the other experimental parameters constant. If homogeneous nucleation plays a major role in the hydrothermal synthesis, the CQDs synthesized by using different filling volumes should have relatively the same size. Nonetheless, we found that the average size of CQDs is inversely correlated with the filling volumes. Particularly, for the hydrothermal syntheses with the filling volumes of 20%, 50%, and 80%, the average size of the CQDs is 15, 13, and 4 nm, respectively. Therefore, the hydrothermal synthesis of CQDs with size-tunability can be achieved by the heterogeneous process associated with the total surface areas between the precursor and reactor.

Highly sensitive and selective antibody microarrays based on a Cy5-antibody complexes coupling ES-biochip for E. coli and Salmonella detection.

Foodborne pathogens are threats in food and a cause of major health issues globally. Microbial safety has become a key concern to eliminate disease-causing pathogens from the food supply. For this purpose, the Cy5 dye conjugated with a double-biotin DNA linkage and a detection antibody (Cy5-Ab complexes) was developed to amplify a foodborne detection signal on a microarray. Additionally, the ES-biochip was designed to attain a visual screening of an antibody microarray for the simultaneous threat detection of Salmonella and Escherichia coli (E. coli). Quantification was also performed by fluorescence. After optimizing the Cy5-Ab complex appendage and enhancing the detection signal from a sandwich immunoassay, high sensitivity and selectivity were observed. The limits of detection for both pathogens in buffer and food samples were 103 CFU mL-1 and less than 9 CFU mL-1 by visual screening and fluorescent intensity quantification, respectively. Mono and duplex responses were not significantly different which means that no cross-reactivity occurred. Uniquely, the assays hold great potential to be used in several fields, such as clinical diagnosis of foodborne microbes, food hygiene screening, and pathogen detection.

Intelligent Wearable Sensors Interconnected with Advanced Wound Dressing Bandages for Contactless Chronic Skin Monitoring: Artificial Intelligence for Predicting Tissue Regeneration.

Toward the adoption of artificial intelligence-enabled wearable sensors interconnected with intelligent medical objects, this contactless multi-intelligent wearable technology provides a solution for healthcare to monitor hard-to-heal wounds and create optimal efficiencies for clinical professionals by minimizing the risk of disease infection. This article addressed a flexible artificial intelligence-guiding (FLEX-AI) wearable sensor that can be operated with a deep artificial neural network (deep ANN) algorithm for chronic wound monitoring via short-range communication toward a seamless, MXENE-attached, radio frequency-tuned, and wound dressing-integrated (SMART-WD) bandage. Based on a supervised training set of on-contact pH-responsive voltage output, the confusion matrix for healing-stage recognition from this deep ANN machine learning revealed an accuracy of 94.6% for the contactless measurement. The core analytical design of these smart bandages integrated wound dressing of poly(vinyl acrylic) gel@PANI/Cu2O NPs for instigating pH-responsive current during the wound healing process. Effectively, a chip-free bandage tag was fabricated with a capacitive Mxene/PTFE electret and adhesive acrylic inductance to match the resonance frequency generated by the intelligent wearable antenna. Under zero-current electrochemical potential, the wound dressing attained a slope of -76 mV/pH. With the higher activation voltage applied toward the wound dressing electrodes, cuprous ions intercalated more into the hybrid PVA gel/PANI shell, resulting in an exponential increase of the two-terminal current response. The healing phase diagram was classified into regimes of fast-curing, slow-curing, and no-curing for skin disease treatment with corticosteroids. Ultimately, the near-field sensing technology offers adequate information for guiding treatment decisions as well as drug effectiveness for wound care.

Target amplification-free detection of urinary microRNA for diabetic nephropathy diagnosis with electrocatalytic reaction.

Diabetic nephropathy (DN) is a serious diabetic complication, usually developed from type II diabetes mellitus (T2DM) and known as type II DN (T2DN). New emerging biomarkers for T2DN are microRNAs (miRNAs) which have been studied for the noninvasive early-stage detection of the disease. In this work, a nucleic acid amplification-free miRNA-124 sensor based on target-induced strand displacement on magnetic beads, and by using methylene blue-loaded silica particles as a label was developed. Measurement methods can be either visual observation, spectrophotometry, or electrochemistry. After incubation and separation of the magnetic particles, a blue-violet solution (564 nm) appeared, depending on the concentration of miRNA displaced. For electrochemical detection, methylene blue on the silica served as a redox mediator for the coupled reaction with ferricyanide in the solution phase. At the electrode surface, ferricyanide was re-reduced to ferrocyanide, and was thus available for further reaction with methylene blue, forming an amplification cycle. After optimization, the total assay time was 60 min, and limits of detection were 1 pM, 6 fM, and 0.65 fM, by the naked eye, spectrophotometry and electrochemistry, respectively. The miRNAs in 42 suspected urine samples from patients suffering from either diabetic nephropathy, diabetes mellitus, or chronic kidney disease were validated by comparing with the droplet digital polymerase chain reaction (ddPCR).

High-performance electrochemical sensing of hazardous pesticide Paraoxon using BiVO4 nano dendrites equipped catalytic strips.

Paraoxon is one of the pesticide that can induce toxicity to nervous system of living organisms. In this work, we focused on synthesizing the catalyst Bismuth Vanadate with the properties that can sense the presence of organophosphorus compounds and characterized them with various characterization methods. The structural studies done by XRD, UV spectroscopy and FTIR spectroscopy. Morphological studies were carried by SEM and TEM. Elemental analysis using XPS spectra. The proposed electrocatalyst was successfully applied as the active electrode material modifying the screen printed carbon electrode for electrochemical sensor applications. The results of the studies indicate that bismuth vanadate modified electrode exhibited four electron transfer process for reduction of nitro group and this lead to the superior electrochemical sensing performance for ethyl Paraoxon with a detection limit of 0.03 µM and good sensitivity 0.345 µA µM-1 cm-2 with excellent reproducibility, repeatability, stability and selectivity over common interferents. Furthermore, the practical application was successfully carried using the proposed modified strips to determine Paraoxon presence in the river water sample with satisfactory results. This proposed catalyst can act as a desirable candidate for the rapid electrochemical sensor.

Ultrasensitive pathogen detection with a rolling circle amplification-empowered multiplex electrochemical DNA sensor.

We report a highly sensitive and selective multiplex assay by empowering an electrochemical DNA sensor with isothermal rolling circle amplification. The assay could simultaneously detect and discriminate three common entero-pathogens in a single reaction, with femtomolar sensitivity. It is useful for field- or resource-limited settings.

A new and high-performance microfluidic analytical device based on Fusion 5 paper for the detection of chili pepper anthracnose pathogen Colletotrichum truncatum.

A microfluidic analytical device based on wax-patterned Fusion 5 paper was designed and fabricated to facilitate early detection and improve control of anthracnose disease. Here, a rapid, specific, on-site, and low operational cost nucleic acid biosensor (ACT-Ct-PAD) based on the actin gene (ACT) and wax-patterned Fusion 5 paper was used to detect the PCR products of Colletotrichum truncatum (Ct), the main causal agent of chili anthracnose in Asia. The sensor was developed by using DNA conjugated gold nanoparticles (AuNPs-DNA) as a detection probe, which will hybridize to a complementary target sequence. Avidin coated mesoporous silica particles were attached to biotin-tagged DNA sequences forming capture probes, which were immobilized on the test and control zones of the device. The hybridization complex (MSP-dsDNA-AuNPs) produces an intense red color, which provides a platform for colorimetric detection. By targeting an actin gene sequence, the ACT-Ct-PAD device allows the detection of Ct DNA within 15 min. The specificity of the sensor was confirmed by the absence of a positive signal for DNA from non-target Colletotrichum species and two different fungal genera. Our wax-patterned Fusion 5 sensor provides a simple tool for the rapid nucleic acid diagnosis with a detection limit down to 17.42 femtomoles. This method has the potential to be applied for protein assay as well; hence, it has a considerable impact on on-site diagnostics.

Lab-on-Eyeglasses to Monitor Kidneys and Strengthen Vulnerable Populations in Pandemics: Machine Learning in Predicting Serum Creatinine Using Tear Creatinine.

The serum creatinine level is commonly recognized as a measure of glomerular filtration rate (GFR) and is defined as an indicator of overall renal health. A typical procedure in determining kidney performance is venipuncture to obtain serum creatinine in the blood, which requires a skilled technician to perform on a laboratory basis and multiple clinical steps to acquire a meaningful result. Recently, wearable sensors have undergone immense development, especially for noninvasive health monitoring without a need for a blood sample. This article addresses a fiber-based sensing device selective for tear creatinine, which was fabricated using a copper-containing benzenedicarboxylate (BDC) metal-organic framework (MOF) bound with graphene oxide-Cu(II) and hybridized with Cu2O nanoparticles (NPs). Density functional theory (DFT) was employed to study the binding energies of creatinine toward the ternary hybrid materials that irreversibly occurred at pendant copper ions attached with the BDC segments. Electrochemical impedance spectroscopy (EIS) was utilized to probe the unique charge-transfer resistances of the derived sensing materials. The single-use modified sensor achieved 95.1% selectivity efficiency toward the determination of tear creatinine contents from 1.6 to 2400 µM of 10 repeated measurements in the presence of interfering species of dopamine, urea, and uric acid. The machine learning with the supervised training estimated 83.3% algorithm accuracy to distinguish among low, moderate, and high normal serum creatinine by evaluating tear creatinine. With only one step of collecting tears, this lab-on-eyeglasses with disposable hybrid textile electrodes selective for tear creatinine may be greatly beneficial for point-of-care (POC) kidney monitoring for vulnerable populations remotely, especially during pandemics.

Clinical evaluation of a developed paper-based Dengue NS1 rapid diagnostic test for febrile illness patients.

OBJECTIVES: This study aimed to evaluate a microfluidic paper-based analytical device (DEN-NS1-PAD) based on a rapid NS1 antigen test for diagnosing dengue at the point of care. METHODS: 219 serum samples from suspected dengue cases were tested with the developed DEN-NS1-PAD and commercial RDT by SD BIOLINE. The results were compared with the nested-PCR results. RESULTS: The limit of detection of DEN-NS1-PAD was 0.78 ng mL-1. It showed 88.89% sensitivity, 86.67% specificity, and a substantial agreement correlation (κ = 0.7522) compared with nested-PCR. In contrast, SD BIOLINE for NS1 (SD-NS1) detection showed 87.88% sensitivity, 90.00% specificity, and had a substantial agreement correlation with nested-PCR (κ = 0.7788). CONCLUSIONS: DEN-NS1-PAD is a valuable tool for diagnosing DENV infections, especially for diagnosed patients with early acute phase samples with high viral load. DEN-NS1-PAD has better sensitivity than SD-NS1 but less specificity.

Aptamer-functionalised magnetic particles for highly selective detection of urinary albumin in clinical samples of diabetic nephropathy and other kidney tract disease.

We report a new highly selective detection platform for human albumin (HA) in urine based on aptamer-functionalised magnetic particles. Magnetic separation and re-dispersion was utilised to expose the HA-bound particles to a methylene blue solution. A second magnetic collection step was then used to allow the methylene blue supernatant to be reduced at an unmodified screen-printed electrode. Since methylene blue adsorbs to HA, the reduction current fell in proportion to HA concentration. There was no interference from compounds such as dopamine, epinephrine, vanillylmandelic acid, normetanephrine, metanephrine and creatinine in artificial urine at the concentrations at which they would be expected to appear. A calibration equation was derived to allow for the effect of pH on the response. This enabled measurement to be made directly in clinical urine samples of varying pH. After optimisation of experimental parameters, the total assay time was 40 min and the limit of detection was between 0.93 and 1.16 µg mL-1, depending on the pH used. HA could be detected up to 400 µg mL-1, covering the range from normoalbuminuria to macroalbuminuria. Analysis of urine samples of patients, with diabatic nephropathy, type I & II diabetes mellitus and chronic kidney disease, from a local hospital showed good agreement with the standard urinary human albumin detection method.

Satellite-Based Sensor for Environmental Heat-Stress Sweat Creatinine Monitoring: The Remote Artificial Intelligence-Assisted Epidermal Wearable Sensing for Health Evaluation.

Wearable human sweat sensors have offered a great prospect in epidermal detection for self-monitoring and health evaluation. These on-body epidermal sensors can be integrated with the Internet of Things (IoT) as augmented diagnostics tools for telehealth applications, especially for noninvasive health monitoring without using blood contents. One of many great benefits in utilizing sweat as biofluid is the capability of instantaneously continuous diagnosis during normal day-to-day activities. Here, we revealed a textile-based sweat sensor selective for perspired creatinine that is prepared by coating poly(vinyl alcohol) (PVA)-Cu2+-poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) and cuprous oxide nanoparticles on stretchable nylon, is equipped with heart rate monitoring and a satellite-communication device to locate wearers, and incorporates machine learning to predict the levels of environmental heat stress. Electrochemical impedance spectroscopy (EIS) was used to investigate different charge-transfer resistances of PVA and PEDOT:PSS with cuprous and cuprite ions induced by single-chain and ionic cross-linking. Furthermore, density function theory (DFT) studies predicted the catalytic binding of sweat creatinine with the sensing materials that occurred at thiophene rings. The hybrid sensor successfully achieved 96.3% selectivity efficacy toward the determination of creatinine contents from 0.4 to 960 µM in the presence of interfering species of glucose, urea, uric acid, and NaCl as well as retained 92.1% selectivity efficacy in the existence of unspecified human sweat interference. Ultimately, the hand-grip portable device can offer the great benefit of continuous health monitoring and provide the location of any wearer. This augmented telemedicine sensor may represent the first remote low-cost and artificial-intelligence-based sensing device selective for heat-stress sweat creatinine.

Electrochemical DNA detection of hepatitis E virus genotype 3 using PbS quantum dot labelling.

The aim of this study was to develop a highly specific electrochemical DNA sensor using functionalized lead sulphide (PbS) quantum dots for hepatitis E virus genotype 3 (HEV3) DNA target detection. Functionalized-PbS quantum dots (QDs) were used as an electrochemical label for the detection of HEV3-DNA target by the technique of square wave anodic stripping voltammetry (SWASV). The functionalized-PbS quantum dots were characterized by UV-vis, FTIR, XRD, TEM and zeta potential techniques. As-prepared, functionalized-PbS quantum dots have an average size of 4.15 ± 1.35 nm. The detection platform exhibited LOD and LOQ values of 1.23 fM and 2.11 fM, respectively. HEV3-DNA target spiked serum is also reported.Graphical abstract.

Salivary Creatinine Detection Using a Cu(I)/Cu(II) Catalyst Layer of a Supercapacitive Hybrid Sensor: A Wireless IoT Device To Monitor Kidney Diseases for Remote Medical Mobility.

The stress-free electrochemical-based sensor equipped with the Internet of Things (IoT) device for salivary creatinine determination was fabricated for point-of-care (POC) diagnosis of advanced kidney disorders. Beneficial and real-time data readout for preventive diagnosis and clinical evaluation of chronic kidney diseases (CKD) at different stages and renal dysfunction can be acquired by noninvasive monitoring of the creatinine amounts in saliva. The direct determination and real-time response of salivary creatinine can be attained using the supercapacitor-based sensor of cuprous oxide nanoparticles entrapped by the synergistically cross-linked poly(acrylic acid) (PAA) gel-Cu2+ and Nafion perfluorinated membrane fabricated on a screen-printed carbon electrode (SPCE). Here, we demonstrated that the degree of renal illness could be evaluated using salivary creatinine detection via a catalytic mechanism as Cu2+ ions bound irreversibly with C═N functional groups of creatinine. Besides, the computer simulation was performed to study the interaction between 5 functional groups of creatinine toward acrylic gel-Cu2+. The linear increment between the obtained anodic currents and creatinine concentrations varying from 1 to 2000 µM was accomplished with a selectivity efficiency of 97.2%. Nyquist plots obtained by electrochemical impedance spectroscopy (EIS) validated that the increment of impedance changes strongly dependent on the amount of detected creatinine both in artificial and in human saliva. The porosity features were observed in this interconnected nanocomposite and correlated with Nafion doping. Successively, the friendly portable device was invented and integrated saliva sampling with miniaturized, low-cost IoT electronics of world-location mapping, representing the first remote medical sensor focusing on salivary creatinine sensing.