Predicting the risk of chronic kidney disease based on uric acid concentration in stones using biosensors integrated with a deep learning-based ANN system.

Elevated levels of uric acid (UA) in the body may not only lead to the formation of stones but also increase the risk of developing chronic kidney disease (CKD). This study presents a biosensor for detecting UA concentration in stones and a deep learning-based artificial neural network (ANN) system for analyzing CKD risk. The biosensor is a screen-printed electrode (SPE) chip, whose surface was modified using oxygen plasma, enabling the detection of UA concentration via cyclic voltammetry. Experimental results show a good linear relationship between UA concentration and anodic peak current within the range of 0.15-5 mM. The surface modification method for this biosensor is simple and cost-effective. The ANN system took age and creatinine values as inputs, utilizing the Chronic_Kidney_Disease dataset and supplementary data from literatures for training. After detecting the UA concentration in stones using the biosensor, the result was converted into serum uric acid concentration, allowing the estimation of creatinine level, which was then used by the ANN to assess the risk of developing CKD. This system can assist urologists in determining whether patients should seek consultation with nephrologists for early diagnosis and treatment.

Identification and Quantification of Extracellular Vesicles: Comparison of SDS-PAGE Analysis and Biosensor Analysis with QCM and IDT Chips.

This study presents and compares two methods for identifying the types of extracellular vesicles (EVs) from different cell lines. Through SDS-PAGE analysis, we discovered that the ratio of CD63 to CD81 in different EVs is consistent and distinct, making it a reliable characteristic for recognizing EVs secreted by cancer cells. However, the electrophoresis and imaging processes may introduce errors in the concentration values, especially at lower concentrations, rendering this method potentially less effective. An alternative approach involves the use of quartz crystal microbalance (QCM) and electroanalytical interdigitated electrode (IDT) biosensors for EV type identification and quantification. The QCM frequency shift caused by EVs is directly proportional to their concentration, while electroanalysis relies on measuring the curvature of the I-V curve as a distinguishing feature, which is also proportional to EV concentration. Linear regression lines for the QCM frequency shift and the electroanalysis curvature of various EV types are plotted separately, enabling the estimation of the corresponding concentration for an unknown EV type on the graphs. By intersecting the results from both biosensors, the unknown EV type can be identified. The biosensor analysis method proves to be an effective means of analyzing both the type and concentration of EVs from different cell lines.

An Electrochemical Biosensor for the Detection of Pulmonary Embolism and Myocardial Infarction.

Due to the clinical similarities between pulmonary embolism (PE) and myocardial infarction (MI), physicians often encounter challenges in promptly distinguishing between them, potentially missing the critical window for the correct emergency response. This paper presents a biosensor, termed the PEMI biosensor, which is designed for the identification and quantitative detection of pulmonary embolism or myocardial infarction. The surface of the working electrode of the PEMI biosensor was modified with graphene oxide and silk fibroin to immobilize the mixture of antibodies. Linear sweep voltammetry was employed to measure the current-to-potential mapping of analytes, with the calculated curvature serving as a judgment index. Experimental results showed that the curvature exhibited a linear correlation with the concentration of antigen FVIII, and a linear inverse correlation with the concentration of antigen cTnI. Given that FVIII and cTnI coexist in humans, the upper and lower limits were determined from the curvatures of a set of normal concentrations of FVIII and cTnI. An analyte with a curvature exceeding the upper limit can be identified as pulmonary embolism, while a curvature falling below the lower limit indicates myocardial infarction. Additionally, the further the curvature deviates from the upper or lower limits, the more severe the condition. The PEMI biosensor can serve as an effective detection platform for physicians.

Impact of frailty on perioperative outcomes following percutaneous nephrolithotomy in older persons: evidence from the US Nationwide Inpatient Sample.

To evaluate the impact of frailty on perioperative outcomes of older patients undergoing PCNL, utilizing the US Nationwide Inpatient Sample (NIS) database. Data of hospitalized patients ≥ 60 years who received PCNL were extracted from the 2010 to 2020 NIS database, and included demographics, clinical, and hospital-related information. Patients were assigned to low (< 5), medium (5-15), and high frailty risk (> 15) groups based on the hospital frailty risk score (HFRS). Associations between frailty risk and perioperative outcomes including total hospital cost were determined using population-weighted linear and logistic regression analyses. Data of 30,829 hospitalized patients were analyzed (mean age 72.5 years; 55% male; 78% white). Multivariable analyses revealed that compared to low frailty risk, increased frailty risk was significantly associated with elevated in-hospital mortality (adjusted odds ratio (aOR) = 10.70, 95% confidence interval (CI): 6.38-18.62), higher incidence of unfavorable discharge (aOR = 5.09, 95% CI: 4.43-5.86), prolonged hospital length of stay (LOS; aOR = 7.67, 95% CI: 6.38-9.22), increased transfusion risk (aOR = 8.05, 95% CI: 6.55-9.90), increased total hospital costs (adjusted Beta = 37.61, 95% CI: 36.39-38.83), and greater risk of complications (aOR = 8.52, 95% CI: 7.69-9.45). Frailty is a significant prognostic indicator of adverse perioperative outcomes in older patients undergoing PCNL, underscoring importance of recognizing and managing frailty in older patients.

A portable point-of-care testing device for forward blood typing with hemophilia diagnosis.

This paper presents a portable point-of-care testing (POCT) device to conduct simultaneous and on-site tests of ABO and Rh(D) forward blood typing and hemophilia diagnosis using only a small amount of human whole blood sample. The POCT device consisted of a spinning module, a measuring circuit, an interdigitated electrode (IDE) for hemophilia diagnosis, and three disposable microfluidic chips for bioassays with anti-A, anti-B, and anti-D, respectively, and measurement of the concentration of factor VIII. Agglutination will occur if red blood cells (RBCs) are exposed to the corresponding antibody. To evaluate the degree of RBC agglutination, a linear sweep voltage, ranging from - 0.5 to + 0.5 V, was applied to the electrodes of the microfluidic chip and the resulting current was measured. For different levels of agglutination, the measured I-V curves were explicitly discriminated, providing five clinical levels from non-agglutination (level 0) to strong agglutination (level 4). The quantitative norm obtained from cubic fitting function of each I-V curve served as the criterion to represent this agglutination level. The ABO blood type was determined by both agglutination levels of the blood sample reacting with anti-A and anti-B. The degree of agglutination with anti-D gave the Rh(D) type. Moreover, the concentration of factor VIII was detected for the determination of hemophilia. Without requiring expensive equipment, this POCT device is especially suitable for usage in emergency or natural disasters to provide quantitative testing in rescue and relief operations.

Quantitative determination of uric acid using paper-based biosensor modified with graphene oxide and 5-amino-1,3,4-thiadiazole-2-thiol.

Uric acid is the primary end product of human purine metabolism and has been regarded as a key parameter in urine and blood for monitoring physiological conditions. This paper presents a paper-based biosensor for a quantitative determination of uric acid using electrochemical detection. The working electrode of the biosensor is modified with graphene oxide (GO) and 5-amino-1,3,4-thiadiazole-2-thiol (ATT) by electropolymerizing ATT on the surface of graphene oxide. In this study, cyclic voltammetry (CV) measurements required only 200 µL of analyte solution. The experimental results showed that the oxidation peak current increased as the concentration of uric acid become higher and exhibited a linear relationship in the concentration range of 0.1-10 mM, indicating that this proposed biosensor has high sensitivity. In addition, this biosensor has good selectivity to detect uric acid because ATT has a specific binding with it. In human blood and body fluids, nitrites may be the only factor that can interfere with the detection of uric acid using this proposed biosensor. Nevertheless, uric acid can be discriminated from nitrite in the CV measurement due to different oxidation potentials. Thus, this proposed paper-based biosensor is a promising tool for detecting uric acid in biological samples.

Droplet-Based Immunosensor for Simultaneous Immunoassays of Multiplex Histidine-Tagged Proteins.

This paper presents a droplet-based immunoassay chip allowing each droplet to be positioned in a passive droplet-positioning cavern under continuous flow. In addition, the chip surface can immobilize any kind of histidine-tagged capture agents for performing simultaneous multiplex immunoassays. Distinct families of monodispersed droplets were generated since a diaphragm, which is a thin elastomeric flap film suspended from the top of the main channel, forms a double T junction for shearing the aqueous liquids by the carrier flow. These two types of monodispersed droplets traverse the main channel to the downstream detection area and enter the passive positioning caverns for further immunoassay. A layer of Ni-Co film was coated on the substrate by electrodeposition in order to immobilize the multiplex histidine-tagged capture molecules. In this study, the tumor suppressor protein p53 and the extracellular signal-related kinase 1 (ERK1) were used as the capture agents. Then, both histidine-tagged proteins p53 and ERK1 were immobilized by the Ni-Co layer in a microarray format for subsequent immunoassay and fluorescence detection. The experimental results show that the detected fluorescence intensity is proportioned to the concentration of the encapsulated content in a small droplet. This proposed droplet-based immunoassay chip can immobilize multiplex histidine-tagged proteins, irrelevant to the species of proteins, to carry out simultaneous immunoassays and allow the operation sequence to be conducted automatically through the manipulation of droplets.

Sperm Movement Control Utilizing Surface Charged Magnetic Nanoparticles.

Oligozoospermia and asthenospermia are significant issues related to male infertility, and clinical treatments for infertility are complicated and expensive. This paper presents a sperm-magnetic controlling technology to manipulate sperm movement utilizing surface charged Fe3O4 magnetic nanoparticles (MNPs). Since the surface membrane of sperm is negatively charged, positively charged MNPs can be attracted to the cell membrane of sperm, but the sperm cells and the negatively charged MNPs will repel each other. Under a magnetic field, the MNPs are magnetized to navigate the sperm cells. Experimental results show that, under a magnetic field intensity of 1.48 T, the translational speed of sperm cells with positively charged MNPs was 100 µm/s, while the speed of sperm cells was 80 µm/s if negatively charged MNPs were added. The translational speed of sperm, adding either positively or negatively charged MNPs, linearly and monotonically increased as the intensity and gradient of the magnetic field elevated. Moreover, the speed of sperm movement is a quadratic function of distance of the magnet location. Positively charged MNPs can drive sperm cells faster, as they are directly attracted to sperm surfaces, which is more effective than driving the sperm by electrical repulsion using negatively charged MNPs. Consequently, this proposed approach using surface charged MNPs to control the movement of sperm cells in vitro provides a simple solution for infertility.

Chamfer-Type Capillary Stop Valve and Its Microfluidic Application to Blood Typing Tests.

This paper presents a novel design of a capillary stop valve with a chamfered side that can be used as a flow regulator to hold an injected microfluid in the valve position in a capillary force-driven microfluidic device. Biochemical analysis can be conducted if the chamfer-type valves are placed at strategic positions according to the test protocol. Hence, the stored reagent can be dragged out of the valve for further reaction when the specimen passes through. However, countercurrent phenomena were observed in the commonly used T-type capillary stop valve (without the chamfered side). In blood typing tests, the countercurrent led to incomplete dragging and the fluid stopped flowing at the complicated mixing channel; thus, the blood typing reaction was attenuated. On the contrary, the chamfer-type valve reduced the countercurrent phenomena and ameliorated the blood typing reaction. Consequently, agglutination results can be easily discriminated from nonagglutination cases.

Exosome purification based on PEG-coated Fe3O4 nanoparticles.

Cancer cells secrete many exosomes, which facilitate metastasis and the later growth of cancer. For early cancer diagnosis, the detection of exosomes is a crucial step. Exosomes exist in biological fluid, such as blood, which contains various proteins. It is necessary to remove the proteins in the biological fluid to avoid test interference. This paper presented a novel method for exosome isolation using Fe3O4 magnetic nanoparticles (MNPs), which were synthesized using the chemical co-precipitation method and then coated with polyethylene glycol (PEG). The experimental results showed that the diameter of the PEG-coated Fe3O4 nanoparticles was about 20 nm, while an agglomerate of MNPs reached hundreds of nanometers in size. In the protein removal experiments, fetal bovine serum (FBS) was adopted as the analyte for bioassays of exosome purification. PEG-coated Fe3O4 MNPs reduced the protein concentration in FBS to 39.89% of the original solution. By observing a particle size distribution of 30~200 nm (the size range of various exosomes), the exosome concentrations were kept the same before and after purification. In the gel electrophoresis experiments, the bands of CD63 (~53 kDa) and CD9 (~22 kDa) revealed that exosomes existed in FBS as well as in the purified solution. However, the bands of the serum albumins (~66 kDa) and the various immunoglobulins (around 160 ~ 188 kDa) in the purified solution's lane explained that most proteins in FBS were removed by PEG-coated Fe3O4 MNPs. When purifying exosomes from serum, protein removal is critical for further exosome investigation. The proposed technique provides a simple and effective method to remove proteins in the serum using the PEG-coated Fe3O4 MNPs.

Determination of degree of RBC agglutination for blood typing using a small quantity of blood sample in a microfluidic system.

Blood typing assay is a critical test to ensure the serological compatibility of a donor and an intended recipient prior to a blood transfusion. This paper presents a microfluidic blood typing system using a small quantity of blood sample to determine the degree of agglutination of red blood cell (RBC). Two measuring methods were proposed: impedimetric measurement and electroanalytical measurement. The charge transfer resistance in the impedimetric measurement and the power parameter in the electroanalytical measurement were used for the analysis of agglutination level. From the experimental results, both measuring methods provide quantitative results, and the parameters are linearly and monotonically related to the degree of RBC agglutination. However, the electroanalytical measurement is more reliable than the impedimetric technique because the impedimetric measurement may suffer from many influencing factors, such as chip conditions. Five levels from non-agglutination (level 0) to strong agglutination (level 4+) can be discriminated in this study, conforming to the clinical requirement to prevent any risks in transfusion.

An Automatic Lab-on-Disc System for Blood Typing.

A blood-typing assay is a critical test to ensure the serological compatibility of a donor and an intended recipient prior to a blood transfusion. This article presents a lab-on-disc blood-typing system to conduct a total of eight assays for a patient, including forward-typing tests, reverse-typing tests, and irregular-antibody tests. These assays are carried out in a microfluidic disc simultaneously. A blood-typing apparatus was designed to automatically manipulate the disc. The blood type can be determined by integrating the results of red blood cell (RBC) agglutination in the microchannels. The experimental results of our current 40 blood samples show that the results agree with those examined in the hospital. The accuracy reaches 97.5%.

Enhancement of Dye-Sensitized Solar Cells Efficiency Using Mixed-Phase TiO2 Nanoparticles as Photoanode.

Dye-sensitized solar cell (DSSC) is a potential candidate to replace conventional silicon-based solar cells because of high efficiency, cheap cost, and lower energy consumption in comparison with silicon chip manufacture. In this report, mixed-phase (anatase and rutile nanoparticles) TiO2 photoanode was synthesized to investigate material characteristics, carriers transport, and photovoltaic performance for future DSSC application. Field-emission scanning electron microscope (SEM), X-ray diffraction (XRD), photoluminescence (PL), and UV-visible spectroscopy were used to characterize mixed TiO2 particles. Subsequently, various mixed-phase TiO2 anodes in DSSC devices were measured by electrical impedance spectra (EIS) and energy efficiency conversion. The overall energy conversion efficiency of DSSC chip was improved as a result of the increase of rutile phase of TiO2 (14%) in anatase matrix. Synergistic effects including TiO2 crystallization, reduction of defect density level in energy band, longer lifetime of photoexcited electrons, and lower resistance of electron pathway all contributed to high efficiency of light energy conversion.

Intelligent Computation for Optimal Fabrication Condition of a Protein Chip with Ni-Co Alloy-Coated Surface.

Based on the principle of immobilized metal affinity chromatography (IMAC), it has been found that a Ni-Co alloy-coated protein chip is able to immobilize functional proteins with a His-tag attached. In this study, an intelligent computational approach was developed to promote the performance and repeatability of a Ni-Co alloy-coated protein chip. This approach was launched out of L18 experiments. Based on the experimental data, the fabrication process model of a Ni-Co protein chip was established by using an artificial neural network, and then an optimal fabrication condition was obtained using the Taguchi genetic algorithm. The result was validated experimentally and compared with a nitrocellulose chip. Consequentially, experimental outcomes revealed that the Ni-Co alloy-coated chip, fabricated using the proposed approach, had the best performance and repeatability compared with the Ni-Co chips of an L18 orthogonal array design and the nitrocellulose chip. Moreover, the low fluorescent background of the chip surface gives a more precise fluorescent detection. Based on a small quantity of experiments, this proposed intelligent computation approach can significantly reduce the experimental cost and improve the product's quality.

Crystallographic structure of Ni-Co coating on the affinity adsorption of histidine-tagged protein.

The principle of immobilized metal affinity chromatography (IMAC) has been recently implemented for protein microarrays for the study of protein abundance and function. Ni-Co film fabricated by electrodeposition is a novel microarray surface in an alloy type for immobilizing histidine-tagged proteins based on IMAC. In this paper, the effects of crystallographic structures and surface properties of Ni-Co coatings, with and without the annealing process, on the immobilization of histidine-tagged proteins were systematically investigated. The experimental results reveal that the stronger hcp texture, due to a higher Co content, results in better affinity adsorption for histidine-tagged biotin. Nevertheless, the allotropic phase transformation from hcp to fcc, due to the annealing process, leads to the decrease of affinity adsorption. The wettability property and the surface roughness of Ni-Co coating are, however, not important factors. Obviously, the crystallographic structure of Ni-Co coating is the dominant factor for the specific affinity adsorption of histidine-tagged protein.

Influence of material properties upon immobilization of histidine-tagged protein on Ni-Co coated chip.

In protein research, protein microarray facilitates high-throughput study of protein abundance and function. An appropriate microarray surface that can be used to immobilize protein samples is a prerequisite for the investigation of molecular interactions. Ni-Co alloy coated protein microarray chip has been found to adsorb histidine-tagged proteins effectively based on the method of immobilized metal affinity chromatography. Due to the ingredient of bi-metallic elements, different electroplating conditions resulted in distinct binding affinities. Therefore, the influence of Ni-Co material properties on the immobilization of histidine-tagged protein was systematically investigated in this study. In the experiments, the contact angle measurement suggested that no strong relationship can be established between the wettability of chip surface and its corresponding protein immobilization. ESCA test demonstrated that the major ingredients of the Ni-Co alloy coated protein microarray chip were Ni and Co. In addition, the XRD test concluded that a Ni-Co protein chip that consists mostly of hcp lattice has better binding capability. SEM micrographs provide direct image evidence. These material tests summarize that the Ni-Co alloy coated protein microarray chip adsorbs His-tagged proteins through its surface morphology. Therefore, it can provide specific binding due to the affinity adsorption between the intermediate metals and the protein.

Microfluidic Platform for Enzyme-Linked and Magnetic Particle-Based Immunoassay.

This article presents design and testing of a microfluidic platform for immunoassay. The method is based on sandwiched ELISA, whereby the primary antibody is immobilized on nitrocelluose and, subsequently, magnetic beads are used as a label to detect the analyte. The chip takes approximately 2 h and 15 min to complete the assay. A Hall Effect sensor using 0.35-µm BioMEMS TSMC technology (Taiwan Semiconductor Manufacturing Company Bio-Micro-Electro-Mechanical Systems) was fabricated to sense the magnetic field from the beads. Furthermore, florescence detection and absorbance measurements from the chip demonstrate successful immunoassay on the chip. In addition, investigation also covers the Hall Effect simulations, mechanical modeling of the bead-protein complex, testing of the microfluidic platform with magnetic beads averaging 10 nm, and measurements with an inductor-based system.

Protein microarray chip with Ni-Co alloy coated surface.

Most protein microarrays based on the theory of immobilized metal affinity chromatography (IMAC) were fabricated using the chelator or compound of mono-metallic ion, such as Ni(2+), to capture the histidine-tagged protein. In this study, a novel protein chip with Ni-Co alloy layer fabricated on the substrate of printed circuit board by electrodeposition was developed. It is an innovative microarray surface with bi-metallic elements, i.e. by means of adding cobalt to enhance the specific binding capability to immobilize functional proteins with His-tag attached. Taguchi method was adopted to determine the optimal electrodeposition condition using L18 orthogonal array. Then, the immunoassay was utilized to investigate the properties of the protein chip, and the signal was detected by confocal scanner. The results show that the alloy coating belongs to codeposition of Ni-Co alloy. Due to the affinity adsorption between intermediate metal and protein, this chip provides specific binding. Compared with Ni-coated chip and nitrocellulose (NC) chip, this Ni-Co alloy chip is a high sensitive protein microarray because of high detected fluorescence intensity with low fluorescent background. The proportion of Ni-Co composition will affect the affinity of electroplated layer with proteins and, consequentially, influence the results of immunoassay. Moreover, the test of long-term sensibility of Ni-Co chip showed that it had better binding capability in the first two weeks for coating buffers of pH 7.4 and pH 9 and the immobilization ability began to decay after the third week. The advantages of this novel protein chip include good performance, high repeatability, and inexpensive.

Dividable membrane with multi-reaction wells for microarray biochips.

This paper presents a multi-well membrane fabricated using polydimethylsiloxane (PDMS) as a part of a microarray biochip that allows dividable incubation chambers to be provided on a single chip. The conditions of the forming temperature, time, and mixing proportion of the materials were investigated to obtain optimal physical absorption with the surface of the chip substrate. To verify the properties of the multi-well chip, immunoassays were performed by the alpha-1-fetoprotein (AFP) antigen sandwich experiment. The results showed that the detection limit reached to the concentration of 10 ng/ml AFP antigen, and that the dynamic range was 30-3000 ng/ml. Attaining excellent physical absorption helps in avoiding cross-contamination or interference between different samples on the same biochip. The merits of dividable multi-well chips include promoting effective use of surface and multiple-sample experiments.