Real Urine Research Articles

A modelling approach to prepare synthetic urine for struvite precipitation studies.

Nutrient recovery from wastewater is an effective strategy to prevent eutrophication and provide value for the treatment process. Human urine is a small but highly nutrient-rich stream in the total flux of domestic wastewater from which struvite (MgNH4PO4.6H2O) could be recovered and used as a fertiliser. Consequently, synthetic urine was used in most struvite precipitation studies, due to biohazard issues in real human urine. A modelling approach was developed to formulate synthetic urine recipes based on elemental urine composition, using matrix solving strategy to select and quantify chemical salts for synthetic urine preparation. The model also included mass balance, chemical speciation, and equilibrium dissociation expression for solution thermodynamics predictions in the formulated urine. In this study, synthetic solutions of fresh and stored urine were assessed with this model using Engineering Equation Solver (EES) software to calculate the quantity of salts, pH, ionic strength, and struvite saturation index. Simulation results in EES were successfully verified using PHREEQC simulations, while model validation comprised the examination of urine composition with their reported recipes.

Ultrastable Gold–Copper Nanoclusters on Nitrogen-Doped Graphene Quantum Dots for Selective Electrochemical and Fluorescence Sensing of Glycine

In this work, we present an ultrastable gold–copper nanocluster on nitrogen-doped graphene quantum dot (AuCuNC@N-GQD), with a stability of ≥1 year, achieved through a galvanic exchange process, which displayed intense solid- and solution-state near-infrared emission. Furthermore, the NC exhibited selective and dual sensing of glycine (GLY) through (nonenzymatic) electrochemical (EC) and fluorescence methods, which is assigned to the unique combination of the strong emission and conducting properties of Au–CuNC and N-GQD, respectively, in the same material and is a first-time report of all the above-mentioned. The limits of detection (LODs) obtained for GLY by EC and fluorescence sensing were 10 nM and 1 μM, respectively and are the lowest LOD values reported hitherto in the respective categories. Compared to the controls, AuCuNC@N-GQDs exhibited a ∼20-fold enhancement with a sensitivity of 0.377 μA μM–1 cm–2. The preferential Au–GLY interaction is considered to be the reason for the selective sensing of GLY by AuCuNC@N-GQD and the improvement in the electronic and conductivity characteristics due to N-GQD to the enhanced sensitivity. The sensing performance was successfully extended to real blood and urine samples spiked with GLY without interference.

Glutamic acid-capped iron oxide quantum dots as fluorescent nanoprobe for tetracycline in urine.

Thefabrication of iron oxide quantum dots (IO-QDs) modified with glutamic acid (Glu) under controllable conditionsis reported. The IO-QDs have been characterized by transmission electron microscopy, spectrofluorometry, powder X-ray diffraction, vibrating sample magnetometry, UV-Vis spectroscopy, X-ray photoelectron spectroscopy,and Fourier-transform infrared spectroscopy. The IO-QDs exhibited good stability towards irradiation, temperature elevations, and ionic strength, and the quantum yield (QY) of IO-QDs was calculated to be 11.91 ± 0.09%. The IO-QDs were furtherly measured at an excitation wavelength of 330nm with emission maxima at 402nm, which were employed to detect tetracycline (TCy) antibiotics, including tetracycline (TCy), chlortetracycline (CTCy), demeclocycline (DmCy), and oxytetracycline (OTCy) in biological samples. The results indicated that TCy, CTCy, DmCy, and OTCy in urine samples show a dynamic workingrange between 0.01 and 80.0μM; 0.01 and 1.0μM; 0.01 and 10μM; and 0.04 and 1.0μM, respectively, with detection limits of 7.69nM, 120.23nM, 18.20nM, and 67.74nM, respectively. The detection was not interfered with by the auto-fluorescence from the matrices. In addition, the obtained recovery in real urine samples suggested that the developed method could be used in practical applications. Therefore, the current study has prospect to developan easy, fast, eco-friendly, and efficient new sensing method for detecting tetracycline antibiotics in biological samples.

Magnetic layered double hydroxides for the sensitive dispersive solid phase microextraction of hippuric acid in urine samples prior to HPLC-UV analysis

The core- shell structural layered double hydroxide (Fe3O4-SiO2-EN@Zn-Al-LDH) was successfully synthesized and applied as a solid sorbent in the magnetic dispersive micro solid-phase-extraction (M-DµSPE) method. It was combined with high-performance liquid chromatography for the trace analysis of hippuric acid (HA) from urine samples. The obtained magnetic layered double hydroxides (LDHs) were characterized by XRD, FT-IR, VSM, FE-SEM, and BET techniques. The characterization analysis indicated that Fe3O4- SiO2- EN@ Zn-Al-LDH has a sufficient surface area and good saturation magnetism. The affecting variables on the extraction of HA by the proposed method were optimized. Excellent adsorption capacity (127.8 mg g−1), wide linearity dynamic range (0.015–500 µg mL−1), and satisfactory limits of detection and quantification (0.055 and 0.014 µg mL−1, respectively) could be obtained under optimum conditions. The good repeatability and low relative standard deviation (7.2 %), low carry-over (2.7%), good matrix effect (93.6%), high reusability (up to 19 times), and an acceptable percent recovery value (97.2%) proved the selectivity and applicability of the proposed method for the extraction of the trace levels of HA in real urine samples.

Magnetic Solid-Phase Microextraction Protocol Based on Didodecyldimethylammonium Bromide-Functionalized Nanoparticles for the Quantification of Epirubicin in Biological Matrices.

Due to epirubicin's (EPI) narrow therapeutic index and risk of cardiotoxicity, it is critical to monitor concentrations of this drug when being used to treat cancer patients. In this study, a simple and fast magnetic solid-phase microextraction (MSPME) protocol for the determination of EPI in plasma and urine samples is developed and tested. Experiments were performed using prepared Fe3O4-based nanoparticles coated with silica and a double-chain surfactant-namely, didodecyldimethylammonium bromide (DDAB)-as a magnetic sorbent. All the prepared samples were analyzed via liquid chromatography coupled with fluorescence detection (LC-FL). The validation parameters indicated good linearity in the range of 0.001-1 µg/mL with a correlation coefficient > 0.9996 for plasma samples, and in the range of 0.001-10 µg/mL with a correlation coefficient > 0.9997 for urine samples. The limit of detection (LOD) and limit of quantification (LOQ) for both matrices were estimated at 0.0005 µg/mL and 0.001 µg/mL, respectively. The analyte recovery after sample pretreatment was 80 ± 5% for the plasma samples and 90 ± 3% for the urine samples. The developed method's applicability for monitoring EPI concentrations was evaluated by employing it to analyze real plasma and urine samples collected from a pediatric cancer patient. The obtained results confirmed the proposed MSPME-based method's usefulness, and enabled the determination of the EPI concentration-time profile in the studied patient. The miniaturization of the sampling procedure, along with the significant reduction in pre-treatment steps, make the proposed protocol a promising alternative to routine approaches to monitoring EPI levels in clinical laboratories.

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.

Magnet Integrated Fabric Phase Sorptive Extraction for the Extraction of Resin Monomers from Human Urine Prior to HPLC Analysis

In this work, a method for the simultaneous determination of four resin monomers: Bisphenol A, bisphenol A methacrylate glycidate, triethyleneglycol-dimethacrylate, and urethane dimethacrylate, from human urine using magnet integrated fabric phase sorptive extraction (MI-FPSE), followed by high performance liquid chromatography (HPLC) diode array detection (HPLC-DAD), is presented. MI-FPSE is a novel configuration of FPSE that incorporates the stirring and extraction mechanism into one device, resulting in an improved extraction kinetic factor. FPSE is a green sample preparation technique that uses a flexible surface, such as cellulose, coated with a polymeric material using sol–gel technology. Poly(tetrahydrofuran) (PTHF) material was selected, due to its higher efficiency in terms of recovery rate among the studied MI-FPSE membranes. Optimization of the extraction process was performed based on several extraction and elution parameters. The method was validated for its linearity, selectivity, accuracy, precision, and stability of the samples. For the four compounds, the LOD and LOQ were 0.170 ng/μL and 0.050 ng/μL, respectively. The relative standard deviation of the method was less than 9.8% and 11.9%, for the within-day and between-day precision, respectively. The relative recoveries were between 85.6 and 105.2% in all cases, showing a good accuracy. The effectiveness of the proposed method was confirmed through successful application to the bioanalysis of real urine samples.

Factors influencing the recovery of organic nitrogen from fresh human urine dosed with organic/inorganic acids and concentrated by evaporation in ambient conditions

To feed the world without transgressing regional and planetary boundaries for nitrogen and phosphorus, one promising strategy is to return nutrients present in domestic wastewater to farmland. This study tested a novel approach for producing bio-based solid fertilisers by concentrating source-separated human urine through acidification and dehydration. Thermodynamic simulations and laboratory experiments were conducted to evaluate changes in chemistry of real fresh urine dosed and dehydrated using two different organic and inorganic acids. The results showed that an acid dose of 1.36 g H2SO4 L−1, 2.86 g H3PO4 L−1, 2.53 g C2H2O4·2H2O L−1 and 5.9 g C6H8O7 L−1 was sufficient to maintain pH ≤3.0 and prevent enzymatic ureolysis in urine during dehydration. Unlike alkaline dehydration using Ca(OH)2 where calcite formation limits the nutrient content of fertiliser products (e.g. <15 % nitrogen), there is greater value proposition in acid dehydration of urine, as the products contain 17.9–21.2 % nitrogen, 1.1–3.6 % phosphorus, 4.2–5.6 % potassium and 15.4–19.4 % carbon. While the treatment recovered all phosphorus, recovery of nitrogen in the solid products was 74 % (±4 %). Follow-up experiments revealed that hydrolytic breakdown of urea to ammonia, chemically or enzymatically, was not the reason for the nitrogen losses. Instead, we posit that urea breaks down to ammonium cyanate, which then reacts with amino and sulfhydryl groups of amino acids excreted in urine. Overall, the organic acids evaluated in this study are promising for decentralised urine treatment, as they are naturally present in food and therefore already excreted in human urine.

Enzyme-based color bar-style lateral flow strip for equipment-free and semi-quantitative determination of urinary oxalate

Urolithiasis is a highly prevalent disease with increasing incidence worldwide, which occurs mainly as calcium oxalate. Therefore, measuring urinary oxalate for the early screening of urolithiasis is of growing significance. However, current approaches for oxalate detection are generally based on specific equipment, thus limiting their point-of-care applications. In this study, a colorimetric lateral flow strip was developed based on enzyme catalysis, and a color bar strategy was utilized for equipment-free and semi-quantitative determination of urinary oxalate, which does not require any image acquisition or processing equipment. Rapid semi-quantitative detection of oxalate is achieved by directly counting the number of color bars that is positively correlated with oxalate concentration. Three colorimetric patterns were compared and optimized, among which the one with 3,3',5,5'-tetramethylbenzidine (TMB) scribes presented the best results with minimized drag impact, washing effects and limited inter-reagent reactions in the lateral flow. Under optimized conditions, the assay showed a detection limit less than 0.3 mM and a detection range of 0.3–0.7 mM that covers the urinary oxalate concentrations for urolithiasis screening. Finally, the strips were verified for real urine sample analysis, validating its potential for oxalate detection and urolithiasis screening in point-of-care applications.

A label-free ultrasensitive microRNA-21 electrochemical biosensor based on MXene (Ti3C2)-reduced graphene oxide-Au nanocomposites

The detection of microRNA is widely used in the early diagnosis of diseases such as cancer and acute kidney injury. In this work, we successfully constructed a label-free ultrasensitive biosensor for the instant detection of miRNA-21. The MXene-reduced graphene oxide (rGO)-Au was synthesized as electrode materials to immobilize DNA probes and MXene-AuPd was used as signal amplification materials. The highly sensitive biosensor had a wide range of linearity from 1 fM to 1 nM, and the limit of detection of as-fabricated biosensor was lower as 0.42 fM under optimized conditions. The biosensor also showed high specificity, outstanding stability and desirable reproducibility, which could also realize the accurate detection of miRNA-21 in real urine samples of both mouse and human with high sensitivity. The label-free electrochemical biosensor based on MXene nanocomposites is a promising candidate for potential applications on the early diagnosis of cancers and acute kidney injury.

Cyanobacteria cultivation on human urine for nutrients recovery

Urine is a nutrient rich stream; it accounts for 70% of the nitrogen load and 40% of the phosphorus load present in domestic wastewater while in volume it only represents 1%. Given the high concentrations of nitrogen (5–7 g N∙L−1) and phosphorus (0.2–0.3 g P∙L−1) in urine, it is more efficient to recover these nutrients from this concentrated stream than from domestic wastewater where they are more diluted. These nutrients can be recovered in form of biomass that could be a source of biobased compounds or could also be used as soil amendment or fertilizer. In this study, the model cyanobacterium Synechocystis sp. PCC6803 was cultivated on synthetic and real, source-separated human urine with different pretreatments to determine if real urine inhibits cyanobacterial growth. Additionally, the nutrient content of urine, including trace elements, was assessed to determine if these are sufficient to support growth to the biomass concentration needed for complete nitrogen and phosphorus recovery. Cultivation of Synechocystis sp. PCC6803 on source separated urine recovered up to 87% of the nitrogen and 99% of the phosphorus in form of biomass, reaching N:P ratios up to 43:1. The biomass reached similar specific growth rates on synthetic urine and source-separated urine demonstrating that there are no negative effects of real urine on growth of Synechocystis sp. PCC6803. Supplementing urine with sulfate, magnesium, iron and trace elements is necessary for balanced growth of Synechocystis sp. PCC6803 and high nutrient recovery.

Green Synthesis of NiO Nanoflakes Using Bitter Gourd Peel, and Their Electrochemical Urea Sensing Application

To determine urea accurately in clinical samples, food samples, dairy products, and agricultural samples, a new analytical method is required, and non-enzymatic methods are preferred due to their low cost and ease of use. In this study, bitter gourd peel biomass waste is utilized to modify and structurally transform nickel oxide (NiO) nanostructures during the low-temperature aqueous chemical growth method. As a result of the high concentration of phytochemicals, the surface was highly sensitive to urea oxidation under alkaline conditions of 0.1 M NaOH. We investigated the structure and shape of NiO nanostructures using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). In spite of their flake-like morphology and excellent crystal quality, NiO nanostructures exhibited cubic phases. An investigation of the effects of bitter gourd juice demonstrated that a large volume of juice produced thin flakes measuring 100 to 200 nanometers in diameter. We are able to detect urea concentrations between 1-9 mM with a detection limit of 0.02 mM using our urea sensor. Additionally, the stability, reproducibility, repeatability, and selectivity of the sensor were examined. A variety of real samples, including milk, blood, urine, wheat flour, and curd, were used to test the non-enzymatic urea sensors. These real samples demonstrated the potential of the electrode device for measuring urea in a routine manner. It is noteworthy that bitter gourd contains phytochemicals that are capable of altering surfaces and activating catalytic reactions. In this way, new materials can be developed for a wide range of applications, including biomedicine, energy production, and environmental protection.

Urinary bio-monitoring of aromatic amine derivatives by new needle trap device packed with the multi-component adsorbent

Aromatic amines are a large group of chemical compounds that have attracted the attention of researchers due to their toxicity and carcinogenicity. This study aimed to develop an efficient method for sampling and analysis of aromatic amines (Aniline, N, N-dimethylaniline, 2-chloroaniline, and 3-chloroaniline) from the vapour phase (headspace) of urine samples. For the implementation of this plan, a needle trap device packed with the three-component adsorbent consisting of nano-Hydroxy Apatite (nHA), Zeolite (Ze), and Metal–Organic Framework (MOF) equipped with GC-FID was employed for the first phase. Examination of the prepared adsorbents was performed by FT-IR, PXRD, and FE-SEM techniques. The optimal value of considerable parameters such as time and temperature of extraction, salt content, and pH were established using the Response Surface Methodology-Central Composite Design (RMS-CCD) method. In this way, the optimal extraction of targeted analytes was accomplished in 41 min at 41 °C with NaCl content of 33.0% (w/v) and pH: 13.0, respectively. Also, the repeatability and reproducibility of the method were calculated to be in the range of 2.2–7.1% and 3.9–8.1%, respectively, which indicates the acceptable precision of the method. Also, the limit of detection (LOD) and limit of quantification (LOQ) were determined in the range of 0.3–32.0 ng.L−1 and 0.8–350.0 ng.L−1, respectively, which proves the high sensitivity of the proposed method. Furthermore, the recovery percent of the extracted analytes was concluded in the range of 97.0–99.0% after 6 and 30 days of the sampling and storage at 25 °C and 4 °C, respectively. Finally, the designed procedure was employed in the analysis of the above-mentioned aromatic amines in the real urine samples. The achieved results illustrate that the three-component absorbent system (nHA;Ze;MOF@NTD) can be introduced as an efficient, fast-response, sensitive, and versatile procedure for trace analysis of the different aromatic amine compounds in public and occupational health.

Innovated single flush on-line solid-phase extraction in bead injection format for flow programming-based determination of creatinine in human urine

Reaction-based assays are commonly automated and miniaturized via flow analysis. However, aggressive reagents can affect or destroy even the chemically resistant manifold during long-term use. Using on-line solid-phase extraction (SPE) can eliminate this drawback and allow for high reproducibility and further advanced automation, as presented in this work. Determination of creatinine in human urine, an important clinical marker, by sequential injection analysis was achieved using bead injection on-line SPE with specific UV spectrophotometric detection, providing the necessary sensitivity and selectivity of the method for bioanalysis. The automated SPE column packing and disposal, calibration, and fast measurement highlighted the improvements in our approach. Variable sample volumes and a single working standard solution eliminated matrix effects, broadened the calibration range, and accelerated the quantification.Our method comprised an injection of 20 μL of 100 × times diluted urine with aqueous acetic acid solution pH 2.4, sorption of creatinine in a strong cation exchanger SPE column, washing out urine matrix with 50% aqueous acetonitrile, and elution of creatinine with 1% ammonium hydroxide. The SPE step was accelerated by a single flush of the column when the eluent/matrix wash/sample/standard zones sequence was created in the pump holding coil, and then the sequence of the zones was flushed into the column at once. The whole process was continually spectrophotometrically detected at 235 nm, subtracted from the signal at 270 nm. A single run duration was less than 3.5 min. Method relative standard deviation was <5.0% (n = 6). A calibration range was linear within the range of 0.02–0.30 μg creatinine (R > 0.999), covering 1.0–15.0 mmol/L creatinine in urine. The standard addition method used two different volumes of a single working standard solution for quantification. Results proved the effectiveness of our improvements in the flow manifold, bead injection, and automated quantification. The accuracy of our method was comparable to the routine enzymatic assay of real urine samples in a clinical laboratory.

Are synthetic cytology images ready for prime time? A comparative assessment of real and synthetic urine cytology images.

The use of synthetic data in pathology has, to date, predominantly been augmenting existing pathology data to improve supervised machine learning algorithms. We present an alternative use case-using synthetic images to augment cytology training when the availability of real-world examples is limited. Moreover, we compare the assessment of real and synthetic urine cytology images by pathology personnel to explore the usefulness of this technology in a real-world setting. Synthetic urine cytology images were generated using a custom-trained conditional StyleGAN3 model. A morphologically balanced 60-image data set of real and synthetic urine cytology images was created for an online image survey system to allow for the assessment of the differences in visual perception between real and synthetic urine cytology images by pathology personnel. A total of 12 participants were recruited to answer the 60-image survey. The study population had a median age of 36.5 years and a median of 5 years of pathology experience. There was no significant difference in diagnostic error rates between real and synthetic images, nor was there a significant difference between subjective image quality scores between real and synthetic images when assessed on an individual observer basis. The ability of Generative Adversarial Networks technology to generate highly realistic urine cytology images was demonstrated. Furthermore, there was no difference in how pathology personnel perceived the subjective quality of synthetic images, nor was there a difference in diagnostic error rates between real and synthetic urine cytology images. This has important implications for the application of Generative Adversarial Networks technology to cytology teaching and learning.

Strong π-Metal Interaction Enables Liquid Interfacial Nanoarray-Molecule Co-assembly for Raman Sensing of Ultratrace Fentanyl Doped in Heroin, Ketamine, Morphine, and Real Urine.

Toward the challenge on reliable determination of trace fentanyl to avoid opioid overdose death in drug crisis, here we realize rapid and direct detection of trace fentanyl in real human urine without pretreatment by a portable surface enhanced Raman spectroscopy (SERS) strategy on liquid/liquid interfacial (LLI) plasmonic arrays. It was observed that fentanyl could interact with the gold nanoparticles (GNPs) surface, facilitate the LLI self-assembly, and consequently amplify the detection sensitivity with a limit of detection (LOD) as low as 1 ng/mL in aqueous solution and 50 ng/mL spiked in urine. Furthermore, we achieve multiplex blind sample recognition and classification of ultratrace fentanyl doped in other illegal drugs, which has extremely low LODs at mass concentrations of 0.02% (2 ng in 10 μg of heroin), 0.02% (2 ng in 10 μg of ketamine), and 0.1% (10 ng in 10 μg of morphine). A logic circuit of the AND gate was constructed for automatic recognition of illegal drugs with or without fentanyl doping. The data-driven analog soft independent modeling model could quickly distinguish fentanyl-doped samples from illegal drugs with 100% specificity. Molecular dynamics (MD) simulation elucidates the underlying molecular mechanism of nanoarray-molecule co-assembly through strong π-metal interactions and the differences in the SERS signal of various drug molecules. It paves a rapid identification, quantification, and classification strategy for trace fentanyl analysis, indicating broad application prospects in response to the opioid epidemic crisis.

Concentrating stabilized human urine using eutectic freeze crystallization for liquid fertilizer production

Resource recovery from source-separated urine can be used to produce fertilizers and provide a more sustainable alternative to mineral fertilizers. Reverse osmosis can be used to remove up to 70% of the water in urine that has been stabilized with Ca(OH)2 and pre-treated with air bubbling. However, further water removal is limited because of membrane scaling and equipment operating pressure limitations. A novel hybrid eutectic freeze crystallization (EFC) and RO system was investigated as a method to concentrate human urine, whilst simultaneously crystallizing salt and ice under EFC conditions. A thermodynamic model was used to predict the type of salts that would crystallize, their associated eutectic temperatures, and how much additional water removal was required (using freeze crystallization) to reach eutectic conditions. This innovative work showed that at eutectic conditions, Na2SO4∙10H2O crystallizes simultaneously with ice in both real and synthetic urine, thus providing a new method to concentrate human urine for liquid fertilizer production. A theoretical mass balance of a hybrid RO-EFC process, including ice washing and recycle streams, showed that 77% of the urea and 96% of the potassium could be recovered with a 95% water removal. The final liquid fertilizer would have a composition of 11.5% N and 3.5% K, and 3.5 kg of Na2SO4∙10H2O could be recovered from 1000 kg of urine. Over 98% of the phosphorus would be recovered as calcium phosphate during the urine stabilization step. A hybrid RO-EFC process would require 60 kWh m−3 of energy, which is substantially less than other concentration methods.

DNA-functionalized carbon quantum dots for electrochemical detection of pyocyanin: A quorum sensing molecule in Pseudomonas aeruginosa

The electrochemical biosensing strategy for pyocyanin (PYO), a virulent quorum-sensing molecule responsible for Pseudomonas aeruginosa infections, was developed by mimicking its extracellular DNA interaction. Calf thymus DNA (ct-DNA) functionalized amine-containing carbon quantum dots (CQDs) were used as a biomimetic receptor for electrochemical sensing of PYO as low as 37 nM in real urine sample. The ct-DNA-based biosensor enabled the selective measurement of PYO in the presence of other interfering species. Calibration and validation of the PYO sensor platform were demonstrated in buffer solution (0–100 μM), microbial culture media (0–100 μM), artificial urine (0–400 μM), and real urine sample (0–250 μM). The sensor capability was successfully implemented for point-of-care (POC) detection of PYO release from Pseudomonas aeruginosa strains during lag and stationary phases. Cross-reactivity of the sensing platform was also tested in other bacterial species such as Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Shigella dysenteriae, Staphylococcus aureus, and Streptococcus pneumoniae. Potential clinical implementation of the ct-DNA-based sensor was manifested in detecting the PYO in P. aeruginosa cultured baby diaper and sanitary napkin. Our results highlight that the newly developed ct-DNA-based sensing platform can be used as a potential candidate for real-time POC diagnosis of Pseudomonas aeruginosa infection in clinical samples.

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.