Real Human Urine Samples Research Articles

Point‐of‐care testing of DNA damage markers‐8‐hydroxy‐2′‐deoxyguanosine based on cobalt‐iron‐platinum‐ruthenium/N doped ordered mesoporous carbon

AbstractIn this work, we achieved point of care detection of DNA damage marker 8‐hydroxy‐2’‐deoxyguanosine (8‐OH‐dG) on tetrapartite metal nanoparticles loaded ordered mesoporous carbon composite nanomaterials (Co‐Fex‐Pt−Pd@NOMC). Nitrogen doping and co‐metal loading were achieved using dopamine as nitrogen, carbon sources and metal linker. In addition, the presence of catechol groups in dopamine with strong affinity for metal ions, make the simultaneous confinement of metals inside and outside the pores of ordered mesoporous carbon. Then, Fe, Pt and Pd metal nanoparticles were introduced to interact with Co nanoparticles to form four‐in‐one alloy nanoparticles by oil bath and carbonisation. The finally formed Co−Fe6‐Pt−Pd@NOMC nanocomposites exhibited excellent catalytic performance for the determination of 8‐OH‐dG. A lower limit of detection (LOD) of 0.044 μM, a wide linear range (0.175 μM–118.375 μM) and strong stability, reproducibility and selectivity were obtained. In addition, Co−Fe6‐Pt−Pd@NOMC realised the detection of 8‐OH‐dG in real human urine sample. At the same time, 8‐OH‐dG after DNA damage and guanine damage were also studied in this work. The electrochemical response of 8‐OH‐dG was combined with DNA damage to verify the mechanism of DNA damage. New solutions and idea were provided for the preparation of inorganic nanocomposites for the detection of 8‐OH‐dG in this work.

Electrochemical sensing of vitamin B6 (pyridoxine) by adapted carbon paste electrode

The recent investigation targets to use adapted carbon paste (CP) with copper nanoparticles (CuNs) operating in a phosphate buffer (PBS) medium with a pH range of 5.0–8.0, to synthesize a novel, susceptible, and simple electrochemical sensor for the detection of one of the most important drugs, vitamin B6. Copper (Cu) is one of the most three common essential trace elements found in the bodies of both humans and animals, along with iron and zinc for all crucial physiological and biochemical functions. Its properties, which are assessed using a variety of methods including scanning electron microscopy (SEM), cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS), have also drawn a lot of attention recently. We considered the effects of pH, buffer, scan rate, interference, and calibration curve. The susceptible electrode's linear calibration curve encompassed concentration values between 8.88 and 1000.0 µM. The calculated limits of detection and quantification were 32.12 and 107.0 µM, respectively. Furthermore, this method was established in real human urine samples and drug validation which have been shown satisfactory results for vitamin B6 detection.

Thiol-functionalized MOF modified 3D printed monolithic microextraction array for analysis of trace Cd and Pb in human urine

Controlling the position, size, and shape of pores is a limitation of traditional monolithic preparation methods. The application of 3D printing technology offers high customizability, allowing the precise printing of pore positions, sizes, and shapes according to the designer's 3D model. Herein, by using Projection Microstereolithography (PμSL), we prepared a 3D-printed monolithic array with post-modification of thiol-functionalized metal-organic framework (MOF), and combined it with inductively coupled plasma mass spectrometry (ICP-MS) for the online analysis of trace Cd and Pb in human urine. To achieve array monolithic microextraction, six 3D-printed monolithic columns were modified with thiol-functionalized MOF-808 (MOF-808-SH), and were then assembled in the 3D printed extraction device incorporating gas valve and scaffold. The MOF-808-SH modified 3D-printed monolithic column exhibits excellent extraction performance to Cd2+ and Pb2+ due to rich active adsorption sites and hierarchical porous structure, and has long life span (>100 reused times). Under the optimized conditions, the limits of detection (LODs) are 3.5 and 17.6 ng L−1 for Cd2+ and Pb2+, respectively, with the relative standard deviations of 4.9 % and 8.2 % (0.1 μg L−1, n = 7), and the sample throughput is 11 h−1. To validate the accuracy of the method, the method was used to determine Cd and Pb in Certified Reference Materials of freeze-dried human urine, the determined results agree well with the certified values. This method was also successfully applied to the determination of trace Cd and Pb in real human urine samples. The developed method offers low LODs, robust anti-interference capability, high sample throughput, long reuse cycles, and automation analysis, showing great potential for the analysis of trace heavy metals in biological samples.

Design and synthesis of a TICT-based red-emissive fluorescent probe for the rapid and selective detection of HSA in human biofluids and live cell imaging.

Here, we report the design and synthesis of a D⋯π⋯A-based fluorescent probe, (E)-4-(4-(dibutylamine)-2-hydroxystyryl)-1-methylquinolin-1-ium (DHMQ), which is nonfluorescent in ∼100% PBS buffer medium due to a twisted intra molecular charge transfer (TICT) phenomenon and it becomes highly fluorescent (∼149 fold) in the presence of human serum albumin (HSA), owing to the restriction of its intramolecular free rotation inside the hydrophobic binding cavity of HSA. The site-selective fluorescence displacement assay and molecular docking studies clearly reveal that DHMQ selectively binds at subdomain IB of HSA. The 3σ/slope method was adopted to determine the limit of detection (LOD) value, which was as low as 2.39 nM in ∼100% PBS medium, indicating its high sensitivity towards HSA. The low dissociation constant value [Kd = (1.066 ± 0.017) μM] suggests a strong complexation between the DHMQ and HSA. Importantly, it has been demonstrated that DHMQ is capable of detecting HSA in real human serum and urine samples and was found to be suitable for live cell imaging of HSA.

Paper-based enzyme-linked biosensor combined with smartphone for simultaneous colorimetric sensing of xanthines and sarcosine

A portable paper-based enzyme-linked biosensor that integrates a multi-enzyme cascade reaction, natural enzyme, and nanozyme with filter paper, combined with smartphones, is proposed for the detection of xanthine (XA) and sarcosine (SA) in urine. The primary biological component of the sensor is horseradish peroxidase (HRP). By chemically modifying cellulose filter paper (CFP) the HRP in horseradish crude extract is specifically immobilized through boron affinity and metal chelation techniques. Furthermore, the incorporation of UiO-66 on CFP had a good synergistic effect on the electron transfer of HRP and the detection of H2O2, significantly increasing the sensor's sensitivity. Under optimized experimental conditions, the sensor demonstrated a dynamic response range of 8–400 μmol L−1 for SA with a minimum detection limit (LOD) of 5 μmol L−1, and a dynamic response range of 10–400 μmol L−1 with an LOD of 8 μmol L−1 for XA. Additionally, the well-designed detection area of the portable test strip simplifies the detection operation, reduces the detection time, and enables rapid on-site analysis. UV-Vis analysis further confirmed the sensor's accuracy in detecting disease markers in urine. The sensing platform has good reproducibility, specificity and stability, suitable for the detection of SA and XA in real human urine samples, and the sensor has the advantages of simple manufacturing, easy operation, strong portability, low reagent consumption, and low cost benefit. Therefore, the development of this paper-based enzyme-linked biosensor offers a novel approach to the detection of disease markers in urine and has potential applications in medical testing.

Development of a dispersive micro solid phase extraction-HPLC method for the simultaneous quantification of antiepileptic drugs in various matrices

Due to the widespread utilization of antiepileptic drugs for seizure control and patient well-being, it is crucial to determine their presence in biological and water samples. This is essential for optimizing therapy, comprehending drug behavior, identifying drug interactions, monitoring environmental contamination, and safeguarding public health and ecology. Hence, a novel method that combines dispersive micro solid phase extraction with HPLC-DAD was developed to simultaneously determine the presence of Lacosamide, Levetiracetam, and Phenytoin. To achieve this, a new sorbent was synthesized using the hydrothermal and sol–gel methods, which consisted of bimetallic MIL-100 (Fe, Ni) on MIL-100 (Mn), SiO2, and Fe3O4 nanoparticles. We compared the extraction capabilities of several sorbents in order to select the most effective one. The optimal ratio of components for the chosen sorbent was determined through the simplex lattice design to enhance its efficiency. The optimized values for SiO2, Fe3O4, and MIL-100 (Fe, Ni) on MIL-100 (Mn) were found to be 0.1, 0.34, and 0.56, respectively. The parameters that affected the dispersive micro solid phase extraction method were optimized using both experimental design and one factor at a time. Under the optimal conditions, the linear range for the detection of Lacosamide, Levetiracetam, and Phenytoin was determined to be 0.1–363.0, 0.3–372.0, and 0.4–435.0 ng mL−1, respectively, with low LODs below 0.13 ng mL−1. Additionally, a preconcentration factor of 492.6, 487.1, and 469.5 was achieved for measuring Lacosamide, Levetiracetam, and Phenytoin, respectively. The intra-day and inter-day relative standard deviations (RSDs) ranged from 3.8 % to 4.6 % and 4.2 % to 5.2 %, respectively. The recoveries and RSDs for analyzing real water, human urine, and serum samples were found to be between 89.6–97.0 % and 4.53–6.44 %, respectively.

Fluorescence and colorimetric dual-mode multienzyme cascade nanoplatform based on CuNCs/FeMn-ZIF-8/PCN for detection of sarcosine.

It is critical to develop a highly efficient and sensitive method for detecting the biomarker sarcosine (SA) of prostate cancer due to its importance for men's health. In our work, a fluorescence (FL) and colorimetric dual-mode multienzyme cascade nanoplatform for SA detection was designed and constructed. CuNCs/FeMn-ZIF-8/PCN nanocomposites with high FL properties and peroxidase-like activity were successfully prepared by encapsulating copper nanoclusters (CuNCs) into FeMn-ZIF-8 and then loaded onto P-doped graphitic carbon nitride (PCN). Furthermore, the nanocomposites served as carriers for the immobilization of sarcosine oxidase (SOX) to construct a high-efficiency dual-mode multienzyme cascade nanoplatform CuNCs/SOX@FeMn-ZIF-8/PCN for the detection of SA. The intermediate H2O2 generated in the cascade caused the FL quenching of nanocomposites and the discoloration of 3,3',5,5'-tetramethylbenzidin. The linear ranges for SA detection in the dual-mode system were 1-100 μM (FL) and 1-200 μM (colorimetric), with detection limits of 0.34 and 0.59 μM, respectively. This nanoplatform exhibited notable repeatability, specificity, and stability, making it suitable for detecting sarcosine in real human urine samples. Therefore, this dual-mode multienzyme cascade nanoplatform would have a potential applicative prospect for detecting SA and other biomarkers in real clinical samples.

Enhanced sensitivity and selectivity of an electrochemical sensor for real-time propofol monitoring in anesthesia

In this study, an electrochemical sensor for the real-time monitoring of propofol (PPF) in anesthesia was developed using molecularly imprinted polymers and reduced graphene oxide-modified glassy carbon electrodes (MIPs/rGO/GCE). To make the electrode, GO was thermally reduced into rGO, which was then electrodeposited on GCE (rGO/GCE), followed by the electropolymerization of MIPs using LiClO4, pyrrole, and PPF (template) solution on rGO/GCE (MIPs/rGO/GCE). The PPF was then taken out of the pyrrole polymer. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS) examinations of surface composition and morphology revealed that electropolymerization MIP on rGO/GCE and reduction and deposition of rGO on GCE were both successful processes. MIPs/rGO/GCE revealed significant sensitivity and selectivity towards PPF in electrochemical tests utilizing cyclic voltammetry (CV) and amperometry. Results demonstrated a linear range from 0.5 to 250 μM that was steady and wide, with a sensitivity of 1.0776 μA/μM and a detection limit value of 0.08 μM. MIPs/rGO/GCE demonstrated outstanding electrocatalytic activity over a broad linear range and a reasonable detection limit value for PPF concentrations. To assess the method's applicability for the analysis of PPF, it was applied to real biological samples of human plasma and urine.

Comprehensive profiling and semi-quantification of exogenous chemicals in human urine using HRMS-based strategies

Chemicals infiltrate our daily experiences through multiple exposure pathways. Human biomonitoring (HBM) is routinely used to comprehensively understand these chemical interactions. Historically, HBM depended on targeted screening methods limited to a relatively small set of chemicals with triple quadrupole instruments typically. However, recent advances in high-resolution mass spectrometry (HRMS) have facilitated the use of broad-scope target, suspect, and non-target strategies, enhancing chemical exposome characterization within acceptable detection limits. Despite these advancements, establishing robust and efficient sample treatment protocols is still essential for trustworthy broad-range chemical analysis. This study sought to validate a methodology leveraging HRMS-based strategies for accurate profiling of exogenous chemicals and related metabolites in urine samples. We evaluated five extraction protocols, each encompassing various chemical classes, such as pharmaceuticals, plastic additives, personal care products, and pesticides, in terms of their extraction recoveries, linearity, matrix effect, sensitivity, and reproducibility. The most effective protocol was extensively validated and subsequently applied to 10 real human urine samples using wide-scope target analysis encompassing over 2000 chemicals. We successfully identified and semi-quantified a total of 36 chemicals using an ionization efficiency-based model, affirming the methodology’s robust performance. Notably, our results dismissed the need for a deconjugation step, a typically labor-intensive and time-consuming process.Graphical

Electroanalytical sensor based on CuInSe2/carbon sphere towards the non‐invasive determination of dopamine

AbstractDopamine (DA) is known as a crucial neurotransmitter synthesized and secreted by dopaminergic neurons and plays a role in regulating human emotions and behaviors. The determination of DA content is of great significance in clinical application and physiological function research. An electroanalytical sensor based on the ternary semiconductor material copper indium selenide (CuInSe2) coated carbon spheres functionalized glassy carbon electrode (CuInSe2@CS/GCE) towards the non‐invasive determination of DA was constructed in this study. The performances of the sensor were characterized using cyclic voltammetry, impedance method, and differential pulse voltammetry. The results show that wrinkled CuInSe2 completely coated on CS. The sensor exhibits good electrochemical kinetics and response signal towards DA, which results from the good electrochemical activity and excellent electroconductibility of transition metal centers of the composite. The determination limit of the proposed sensor towards DA is 0.59 μM (S/N=3), and the linear measuring range is between 1–800 μM. In addition, the sensor exhibits desirable long‐term robustness, reproducibility, repetitiveness, and interference immunity. In the non‐invasive determination towards real samples of human urine and sweat, the sensor provides good recovery rate and small determination deviation.

Tablet-Based Sensor: A Stable and User-Friendly Tool for Point-of-Care Detection of Glucose in Urine.

The colorimetric detection of glucose in urine through enzymatic reactions offers a low-cost and non-invasive method to aid in diabetes management. Nonetheless, the vulnerability of enzymes to environmental conditions, particularly elevated temperatures, and their activity loss pose significant challenges for transportation and storage. In this work, we developed a stable and portable tablet sensor as a user-friendly platform for glucose monitoring. This innovative device encapsulates glucose oxidase and horseradish peroxidase enzymes with dextran, transforming them into solid tablets and ensuring enhanced stability and practicality. The enzymatic tablet-based sensor detected glucose in urine samples within 5 min, using 3,3',5,5'-tetramethylbenzidine (TMB) as the indicator. The tablet sensor exhibited responsive performance within the clinically relevant range of 0-6 mM glucose, with a limit of detection of 0.013 mM. Furthermore, the tablets detected glucose in spiked real human urine samples, without pre-processing, with high precision. Additionally, with regard to thermal stability, the enzyme tablets better maintained their activity at an elevated temperature as high as 60 °C compared to the solution-phase enzymes, demonstrating the enhanced stability of the enzymes under harsh conditions. The availability of these stable and portable tablet sensors will greatly ease the transportation and application of glucose sensors, enhancing the accessibility of glucose monitoring, particularly in resource-limited settings.

Hg2+ detection and information encryption of new [1+1] lanthanide cluster

The sensing of heavy metal ion and information encryption are two very important research areas. Therefore, developing multi-functional materials capable of sensing heavy metal ions and encrypting information is highly important. In this work, three [1 + 1] lanthanide clusters [Ln(TFBA)3(dmp) (H2O)2]2 (Ln = Tb3+Tb1+1, Eu3+Eu1+1, Gd3+Gd1+1, HTFBA = 2,3,4,5-tetrafluorobenzoic acid, dmp = 4,7-dimethyl-1,10-phenanthroline) were designed and synthesized. Among them, Tb1+1 shows excellent luminescence sensing towards Hg2+ (Ex = 350 nm, Em = 545 nm). Results demonstrates the sensing with high selectivity, strong anti-interference, 20-s response time, high accuracy, excellent linear relationship in 0–20.0 μM, and a very low limit of detection (0.02 ppb). Furthermore, paper strips based on Tb1+1 is fabricated for visual detection of Hg2+ in real samples of tap water, lake water, human urine, and human serum. More interestingly, a new method for confidentiality of information is realized through multi-color anti-counterfeiting patterns with the [1 + 1] lanthanide cluster ink, based on the luminescence “on-off” sensing towards Hg2+.

Hydrothermal synthesis of cobalt germanium oxide supported with carbon-based graphitic carbon nitride for electrochemical determination of ornidazole

In recent decades, nitroimidazole derivatives have played an effectual role against bacterial and protozoan infections that can be used as anti-cancer and antibiotic drugs. Ornidazole (ORD) consists of a major 5-imidazole nucleus which complements to first nitro groups, ORD invades into lipid tissue and other nitroimidazole derivatives. The periodic intake of ORD orally causes side effects of headache, nausea, vomiting, and breathing difficulties such effects need potential monitoring and develop essential electrochemical sensing toward ORD. In this study, we developed a ternary cobalt germanium oxide (Co2GeO4) nanoparticle prepared by a facile hydrothermal method and followed by calcination. The carbon-based graphitic carbon nitride (GCN, g-C3N4) nanosheets were therefore supported for electrochemical sensing applications in order to improve the features like the catalytic activity, electrical conductivity, and active surface area of Co2GeO4 composites. The structural, chemical composition, and morphological properties of samples were characterized. Subsequently, the fabrication of cobalt germanium oxide with graphitic carbon nitride (Co2GeO4/GCN) was modified over a screen-printed carbon electrode (SPCE) towards electrochemical detection of ORD. Electrochemical measurements were recorded by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) for the determination of ORD. The Co2GeO4/GCN nanocomposite exhibits a wide linear range response of 0.049–94.9 μM in DPV with a nanomolar limit of detection of 7.2 nM of ORD and a high sensitivity of 2.66 µA µM−1 cm−2. An interference study was carried out for the Co2GeO4/GCN nanocomposite in the existence of hazardous metals, biological compounds, and similar drugs for examining the selectivity of the sensor. The proposed Co2GeO4/GCN nanocomposite reveals superior sensing selectivity towards ORD; hence, repeatability, reproducibility, and storage stability were recorded in their RSD and found to be less than 0.4%, adding to this practical feasibility of the sensor analyzed by real samples of blood serum & human urine with exceptional recovery percentages.

Determination of 1,3-Diphenylguanidine, 1,3-Di-o-tolylguanidine, and 1,2,3-Triphenylguanidine in Human Urine Using Liquid Chromatography-Tandem Mass Spectrometry.

1,3-Diphenylguanidine (DPG), 1,3-di-o-tolylguanidine (DTG), and 1,2,3-triphenylguanidine (TPG) are rubber additives widely present in the indoor environment. Nevertheless, little is known about their human exposure. We developed a method for the quantification of DPG, DTG, and TPG in human urine, using high-performance liquid chromatography-tandem mass spectrometry. The quantitative analysis of target analytes at parts-per-trillion levels in urine was optimized using hydrophilic-lipophilic balanced solid-phase extraction and isotopic dilution. The method limits of detection and quantification were in the range of 0.002-0.02 and 0.005-0.05 ng/mL, respectively. The recoveries of all analytes in human urine fortified at 1, 5, 10, and 20 ng/mL concentrations were in the range of 75.3-111%, with standard deviations of 0.7-4%. The repeated measurement of similarly fortified human urine yielded intra-day and inter-day variations of 0.47-3.90 and 0.66-3.76%, respectively. The validated method was applied in the measurement of DPG, DTG, and TPG in real human urine samples, which revealed the occurrence of DPG in children's urine samples (n = 15) with a detection frequency of 73% and at a median concentration of 0.05 ng/mL. DPG was found in 20% of adults' urine samples (n = 20).

Nitazoxanide and azithromycin for the early treatment of COVID‐19: A multi‐spectroscopic, biochemical and computational drug–drug interaction study

AbstractHerein, we present an experimental and theoretical drug–drug interaction study between nitazoxanide (NTZ) and azithromycin (AZT) in an aqueous solution. Interaction was studied by using UV/Vis, fluorescence, attenuated total reflectance‐fourier transform infrared (ATR‐FTIR), and circular dichroism (CD) spectroscopy, while molecular docking studies were performed to establish the interaction computationally. A bright yellow color was observed when the two drugs interacted, giving a hyperchromic band at 420 nm. The rate of absorbance was linearly increased by increasing drug concentrations and in a time‐dependent manner. Stability of the interaction complex (i.e., NTZ: AZT) was measured at variable temperatures (25–80°C), pH (5.0–10.0) and ionic strength (0.05–2.0 M NaCl), and not only proved stable but also retained antimicrobial potential with reduced cellular toxicity. Mole ratio and Job's method of continuous variations were used to establish the binding stoichiometry and found to be 2:1. The calculated binding constant (kb = 8,400 M−1) and Gibb's free energy (ΔG° = −22.4 KJ/mol) also suggested an energetically favorable interaction. FTIR spectra of NTZ: AZT complex in comparison with two drugs alone revealed significant interaction which was nicely complemented by molecular docking studies. Interaction was also successfully demonstrated in presence of carrier protein HSA and by spiking the two drugs in real samples of human plasma and urine.

Highly selective electrochemical quantitation of creatinine based on its chemical reaction with 3,5-dinitrobenzoate

A simple and reliable method for creatinine quantitation was developed for urine-based diagnosis as creatinine is an internal standard molecule for the calibration of fluctuating urinary concentration. Herein, the quantitation of creatinine in artificial urine was performed in the range of 1–30 mM, covering the normal concentration of human urine, using 3,5-dinitrobenzoate (3,5-DNB) as an electrochemical probe molecule. The chemical interference from various urinary species, including urea, uric acid, ammonia, ascorbic acid, alcohol, albumin, bilirubin, acetaminophen, and glucose, is confirmed to be significantly suppressed when the reaction of creatinine and 3,5-DNB is limited to 5 min with an increased OH– concentration. Additionally, the reliability of this method is confirmed for the use of real human urine samples by comparing the data obtained from this and with that of the conventional method.

Multi-Parameter Detection of Urine Based on Electropolymerized PANI: PSS/AuNPs/SPCE

Urine analysis is widely used in clinical practice to indicate human heathy status and is important for diagnosing chronic kidney disease (CKD). Ammonium ions (NH4+), urea, and creatinine metabolites are main clinical indicators in urine analysis of CKD patients. In this paper, NH4+ selective electrodes were prepared using electropolymerized polyaniline-polystyrene sulfonate (PANI: PSS), and urea- and creatinine-sensing electrodes were prepared by modifying urease and creatinine deiminase, respectively. First, PANI: PSS was modified on the surface of an AuNPs-modified screen-printed electrode, as a NH4+-sensitive film. The experimental results showed that the detection range of the NH4+ selective electrode was 0.5~40 mM, and the sensitivity reached 192.6 mA M-1 cm-2 with good selectivity, consistency, and stability. Based on the NH4+-sensitive film, urease and creatinine deaminase were modified by enzyme immobilization technology to achieve urea and creatinine detection, respectively. Finally, we further integrated NH4+, urea, and creatinine electrodes into a paper-based device and tested real human urine samples. In summary, this multi-parameter urine testing device offers the potential for point-of-care testing of urine and benefits the efficient chronic kidney disease management.

A smartphone integrated paper (SIP)-based platform for rapid and on-site screening of urinary tract infections

We present a smartphone integrated paper (SIP)-based system that enables accurate screening of urinary tract infections (UTIs) by directly identifying white blood cells (WBCs) in human urine samples. The SIP platform mainly consists of a paper-based capillaric filter and a smartphone-integrated fluorescence microscope. A paper filtration device allows a low-cost, simple method for selectively dying and isolating target WBCs in urine with more than 95% collection efficiency using capillary action through paper layers with several different pore sizes without extra pumps and tubes typically required for fluidic actuation in microfluidic systems. Furthermore, an integrated smartphone can be conveniently used for fluorescence imaging of the stained WBCs and microscopic analysis to rapidly provide UTI diagnostic results at the point of care without the need of bulky laboratory equipment and specialized training. The fabrication process for the SIP platform is simple and cost-effective, being beneficial for resource-limited field applications. We have experimentally demonstrated the capability of the SIP for isolation of target WBCs in a urine solution (more than 95% selectivity) using the paper capillaric filter, the effectiveness of the smartphone microscope for fluorescence imaging of urine solutions with 14.4 × magnification over a field of view of ∼12.25 mm2, the reliability of the platform’s cell counting with the 96.67% sensitivity and 100% specificity, and successful differentiation of the real urine samples between UTI patient and healthy person. The entire screening processes from filtration to quantification of WBCs in real human urine samples were rapidly completed within 10 min, showing its potential for point-of-care applications. The SIP technology provides a low-cost, rapid, and portable UTI diagnostic tool that can improve the access of accurate test results to developing areas and thus reduce suffering by speeding up therapy timelines.

Engineered detection zone to enhance color uniformity on paper microfluidics fabricated via Parafilm®-heating-laser-cutting

In this article, we first report a simple fabrication technique to create Parafilm®-laminated microfluidic paper-based analytical devices (µPADs) with a high resolution and then introduce novel engineered detection zones (D-zones) to enhance color uniformity without any chemical modifications. The Parafilm®-heating-laser cutting fabrication method comprises of three steps: 1) flattening a Parafilm® layer on paper, 2) heating in an oven at 90 °C for 30 min, and 3) CO2 laser ablation of the patterns. This method enabled laminated µPADs with a minimum barrier width of 172 ± 15 µm, with resistance to various organic solvents and surfactant solutions. Using this technique, µPADs with two types of engineered D-zones were fabricated. The multi-inlet D-zone had four micro-inlets (<500 µm width), enabling sample entrance into the D-zone from four directions simultaneously towards the center. The segmented D-zone had four segments each with its own micro-inlet allowing for separate reactions to occur in miniaturized segments simultaneously. Using an enzymatic glucose assay for the colorimetric reaction, the multi-inlet and segmented D-zones significantly decreased color gradient from 28.77 ± 1.49 to 12.35 ± 1.18 and 8.95 ± 0.98 %, respectively, compared to the conventional devices. We further used the µPADs with segmented D-zones for the detection of glucose in artificial urine in the clinically relevant range of 2–50 mM, where R2 > 0.99 of the fitted curve showed an excellent correlation between the generated signals and the glucose concentrations. Also, compared to the conventional devices, the engineered D-zones showed improved precision and reproducibility and a better linear range. Finally, spiked real human urine samples were tested, demonstrating the applicability of the engineered devices for real-world applications. Overall, with a simple fabrication method and a novel design for color uniformity, this paper contributes to the advancement of µPADs and paves the way towards commercialization.

Single-step electropolymerization on a printed sensor towards a conductive thin film polymer for the simultaneous determination of drug metabolites: 5-aminosalicylic acid and sulfapyridine.

Amino acid conductive polymers can easily form a thin film on a sensor surface by an electrochemical process. Therefore, we are pioneers in reporting the electropolymerization of L-methionine on the surface of a screen-printed graphene electrode to obtain a disposable electrochemical sensor for determining drug metabolites (5-aminosalicylic acid (5-ASA) and sulfapyridine (SPD)) of sulfasalazine (SSZ) simultaneously. In this work, the developed sensor was facilely created through a single step of electropolymerization under mild conditions (0.1 M phosphate buffer pH 7.0) using cyclic voltammetry. Important parameters in the synthesis process were systematically investigated followed by surface composition and morphology studies. Then, analytical performances, comprising sensitivity, selectivity, stability, reproducibility, and sample preparation, were carefully evaluated. Under optimal conditions, the proposed methodology demonstrated a highly sensitive and selective simultaneous detection of 5-ASA and SPD with wide linear dynamic ranges of 1-50 μM and 80-250 μM and low detection limits of 0.60 and 0.57 μM for 5-ASA and SPD, respectively. To evaluate the potential of the designed sensor, it was successfully applied by simultaneously determining 5-ASA and SPD in real human urine samples on the same day (intra-day study) and on three different days (inter-day study).