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Ultrathin Cu-TCPP Nanosheet-Based Electrochemical Microsensor for Detecting the Immunosuppressive Drug Mycophenolic Acid
(2023-12-22)
Deng, Mingshi
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Jin, Wei
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Yang, Wenjuan
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Tian, Lingling
;
Gao, Xinghua
Mycophenolic acid (MPA), which is a potent immunosuppressant, has been widely used to prevent organ rejection after organ transplantation. In clinical practice, it is essential to monitor the free MPA concentration. Herein, convenient and fast electrochemical microsensing technology is developed for directly detecting the MPA concentration. To implement this method, ultrathin copper-based metal-organic framework (Cu-MOF) nanosheets with a thickness of about 6.6 nm are used to detect MPA. An analysis of electrochemical behavior reveals the direct electrochemical catalytic oxidation mechanism of MPA molecules on a Cu(II) tetrakis(4-carboxyphenyl)porphyrin (Cu-TCPP)-modified electrode. Furthermore, electrochemical testing results show that the ultrathin Cu-TCPP nanosheet-based microsensor exhibits high sensitivity and specificity for MPA in the nano- to micromolar range, with a detection limit of 10 nM. X-ray absorption spectroscopy (XAS) characterization reveals that the unsaturated metal ions in ultrathin nanosheets are the active sites responsible for boosting the catalytic oxidation of MPA molecules. High-performance liquid chromatography-tandem mass spectrometry further shows the catalytic oxidation product of MPA and that the phenolic hydroxyl group in the MPA molecule is the active site where the catalytic reaction occurs. The considerable sensing performance of the Cu-TCPP nanosheet-based microsensor proves that it is possible to develop a fast and convenient method for the direct high-frequency monitoring of immunosuppressive drugs.
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Electrochemically Non-Enzymatic Urea Estimation in Human Dialysate Waste Using Indirect NiOOH-Urea Oxidation
(2023-01-01)
Janyasupab, Metini
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Asavakijthananont, Narawee
;
Chanlek, Narong
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Chio-Srichan, Sirinart
;
Zhang, Yuan
Non-enzymatic urea detection in human dialysate offers a sustainable and spontaneous platform for advanced analysis and monitoring. This study investigated urea estimation in dialysate by using an indirect urea oxidation of nickel on nitrogen doped carbon with an incorporation of surface roughness (R<inf>f</inf>) and double layer current (I<inf>dl</inf>). Fascinatingly, the second oxidation peak on (reverse) cathodic scan at 0.42 V vs Ag/AgCl in cyclic voltammetry and the first peak of differential pulse voltammetry (DPV) after background subtraction were evidenced to the exploited NiOOH binding with urea, concurrently with the regeneration of Ni(OH)<inf>2</inf>. In presence of more urea, the decreasing trends of the oxidation peaks in both techniques were observed and capable of determining urea concentrations in human dialysate. In consideration of actual reaction current, the measured total current after background subtraction in fresh simulated dialysate provides the sensitivity of −5.136 × 10−5 A.mM−1 (R2 = 0.998) and limit of detection of 60.2 μM in 1-5 mM linear range. For validation in patients’ dialysate, the total current peak was normalized by R<inf>f</inf> and subtracted from I<inf>dl</inf>, resulting in excellent urea estimation with recovery percentage between 99.18 and 102.68 in comparison to that of clinical standard, offering future prognostic monitoring and wearable artificial kidney.
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1T-Phase molybdenum sulfide/cobalt oxide nanopillars hybrid nanostructure coupled with nitrogen-doped carbon thin-film as high efficiency electrocatalyst for oxygen evolution
(2022-02-15)
Ying, Zi
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Lv, Yu
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Song, Haixiang
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Ma, Yujie
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Chen, Riming
High efficient and durable catalysts are always needed to lower the kinetic barriers as well as prolong the service life associated with oxygen evolution reaction (OER). Herein, a sequential synthetic strategy is considered to prepare a hierarchical nanostructure, in which each component can be configured to achieve their full potential so that endows the resulting nanocatalyst a good overall performance. In order to realize this, well-organized cobalt oxide (Co<inf>3</inf>O<inf>4</inf>) nanopillars are firstly grown onto ultrathin 1T-molybdenum sulfide (1T-MoS<inf>2</inf>) to obtain high surface area electrocatalyst, providing electron transfer pathways and structural stability. After that, zeolitic imidazolate framework-67 (ZIF-67) derived carbonization film is further in situ deposited on the surface of nanopillars to generate plentiful active sites, thereby accelerating OER kinetics. Based on the combination of different components, the electron transfer capability, catalytic activity and durability are optimized and fully implemented. The obtained nanocatalyst (defined as 1T-MoS<inf>2</inf>/Co<inf>3</inf>O<inf>4</inf>/CN) exhibits the superior OER catalytic ability with the overpotential of 202 mV and Tafel slope of 57 mV·dec−1 at 10 mA·cm−2 in 0.1 M KOH, and good durability with a minor chronoamperometric decay of 9.15 % after 60,000 s of polarization.
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Low-Cost PM 2.5 Sensor and Cost-Effective Air Purification Study for Household Implementation
(2022-01-01)
Janyasupab, Metini
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Yongwiwat, Jaturun
Particulate matters (PM) 2.5 is one of the most growing concerns during the past few years. Most effectively, air purifiers can reduce harmful PM in any closed spaces. However, economical affordability and health awareness still becomes a limit of device's viability, especially for lower middle-income countries. This study aims to investigate a low-cost PM 2.5 sensor (LCPMS) to quantify a cost-effective household solution of air purification by applying HEP A filter on a cooling fan. In evaluation of various factors involved in venting positions, filter layers, layout configurations, LCPMS can provide quantitative information to determine feasibility of cost-effective solution, reducing air pollution at the efficiency of 91.23% and 96.44% for 1 and 2 filters, respectively, in a range of 43 to 264 μg.m-3 PM2.5 level. Ultimately, the solution was validated on 22-inch conventional fan in 27-m2 room, explicitly confirming a substantial reduction of indoor air pollution by 64.4 % within 20 minutes at a cost less than 5 USD.
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Study of ni2+/ni3+ redox couple and electrocatalytic responses of ni on nitrogen-doped carbon for urea non-enzymatic detection
(2021-01-01)
Asavakijthananont, Narawee
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Janyasupab, Metini
A novel redox couple of metallic nickel (Ni) catalyst can become a great candidate of non-enzymatic detection. By taking advantage of fast electron transfer, Ni redox couples can be tailored as pseudo-enzyme in urea measurement. In this study, Ni catalyst on nitrogen doped carbon (Ni-NC) was synthesized and characterized morphological, elemental, and electrocatalytic properties in comparison to different configuration of pure nickel (Ni), Ni with carbon (Ni-C), and bare carbon electrode, assessed by cyclic voltammetry and differential pulse voltammetry. By examining various Ni redox couples in rapid electron transfer process, the prominent anodic and cathodic peaks of Ni2+/Ni3+ were applicable to detect urea in the detection range of 1-20 mM, with an excellent sensitivity and relative standard deviation of 1.634 µA.mM-1 (R2 of 0.989) and 4.89%, respectively. Therefore, Ni-NC can find practical applications for material sensing device toward non-enzymatic urea measurement.
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RhIr@MoS2 nanohybrids based disposable microsensor for the point-of-care testing of NADH in real human serum
(2020-08-01)
Ji, Dongqing
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Ying, Zi
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Zhang, Yuan
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Chen, Wei
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Janyasupab, Metini
Dihydronicotinamide adenine dinucleotide (NADH) is an important enzyme in all living cells, which is found to be abnormally expressed in cancer cells. Since it is redox-active, an electrochemical detection method would be suitable for monitoring its concentration in biological fluids. Here we present a strategy for specific determination of NADH in real human serum by using RhIr@MoS<inf>2</inf> nanohybrids based microsensor. To implement the protocol, RhIr nanocrysrals are in-situ grown onto MoS<inf>2</inf> interlayers forming a nanohybrid structure (RhIr@MoS<inf>2</inf>). After being locally deposited on an electrochemical microsensor, it could be used for the analysis of NADH. The developed RhIr@MoS<inf>2</inf> nanohybrids based microsensor possesses the ability for analyzing NADH at the applied potential of 0.07 V (much lower than most reported values). The detection limit is evaluated as low as 1 nmol/L even in bovine serum albumin (BSA) media. In addition, the sampling analysis of human serum from cancer patients and health controls shows that the microsensor displays good diagnostic sensitivity and specificity, illustrating that this developed detection technique is a relatively accurate method for measuring NADH in biological fluids. The proposed electrochemical microsensor assay also owns the benefits of convenience, disposable and easy processing, which make it a great possibility for future point-of-care cancer diagnosis.
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Phase-Regulated Sensing Mechanism of MoS2 Based Nanohybrids toward Point-of-Care Prostate Cancer Diagnosis
(2020-05-01)
Ying, Zi
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Feng, Lingyan
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Ji, Dongqing
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Zhang, Yuan
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Chen, Wei
Alpha-methylacyl-CoA racemase (AMACR) has been proven to be consistently overexpressed in prostate cancer epitheliums, and is expected to act as a positive biomarker for the diagnosis of prostate carcinoma in clinical practice. Here, a strategy for specific determination of AMACR in real human serum by using an electrochemical microsensor system is presented. In order to implement the protocol, a self-organized nanohybrid consisting of metal nanopillars in a 2D MoS<inf>2</inf> matrix is developed as material for the sensing interface. The testing signal outputs are strongly enhanced with the presence of the nanohybrids owing to that the metal pillars provide an efficient mass difussion and electron transfer path to the MoS<inf>2</inf> film surface. Furthermore, the phase-regulated sensing mechanism over MoS<inf>2</inf> is noticed and demonstrated by density functional theory calculation and experiments. The explored MoS<inf>2</inf> based nanohybrids are employed for the fabrication of an electrochemical microsensor, presenting good linear relationship in both ng µL−1 and pg µL−1 ranges for AMACR quantification. The sampling analysis of human serum indicates that this microsensor has good diagnostic specificity and sensitivity toward AMACR. The proposed electrochemical microsensor system also demonstrates the advantages of convenience, cost-effectiveness, and disposability, resulting in a potential integrated microsystem for point-of-care prostate cancer diagnosis.
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A comparative study of non-enzymatic glucose detection in artificial human urine and human urine specimens by using mesoporous bimetallic cobalt-iron supported N-doped graphene biosensor based on differential pulse voltammetry
(2019-05-01)
Janyasupab, Metini
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Liu, Chen Wei
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Chanlek, Narong
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Chio-Srichan, Sirinart
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Promptmas, Chamras
Development of non-invasive glucose measurement allows future advancement of smart sensing platform for diagnostic technology. Especially for endocrine disorders, advanced kidney diseases, and diabetes, monitoring excessive glucose level in urine can provide invaluable information for clinical prognosis and preventive healthcare. Herein, we present a comparative electrochemical study of cobalt/iron (CoFe) catalyst on nitrogen-doped graphene (NG) for non-enzymatic glucose detection, carried out in physiological pH urine including (i) modified artificial urine medium (mAUM), (ii) commercial standard urine (Surine), and (iii) human urine specimens. With no requirement of strong alkaline addition, catalytic properties of CoFe-NG were assessed by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on a glassy carbon rotating disk electrode. Upon successive glucose additions from 0 to 3 mM, DPV results revealed two anodic peaks at +0.18 V and +0.42 V versus Ag/AgCl, corresponding to Co3+ and Co4+ as a result of glucose binding in urine. By evaluating at +0.18 V, the sensitivities of CoFe-NG were estimated to be 16.77 (R2 = 0.987), 45.36 (R2 = 0.988), and 20.26 (R2 = 0.991) μA mM−1 cm−2 with the limit of detection of 0.25, 0.07, and 0.19 mM in mAUM, Surine, and human urine specimen with low serum creatinine, respectively. Furthermore, the effects of CoFe on graphene (G) and carbon Vulcan XC-72 (C) were also studied in comparison of NG on the bimetal. Interestingly, CoFe-C showed a good electrochemical trend in glucose detection in urine. However, negligible catalytic activity was presented in CoFe-G. Thus, electrochemical responses of CoFe-C were also further studied in the comparison of CoFe-NG in each type of urine. Overall, CoFe-NG outperformed CoFe-C in all types of urine and exhibited an excellent anti-interference property toward uric acid, thereby suggesting great potential for the next generation of glucose sensing platform in urine.
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Development of wireless based potentiostat in biomedical applications
(2019-03-01)
Janyasupab, Metini
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Asavakijthananont, Narawee
Wirelessly integrated and portable electronics designs of analytical systems are of great importance to support future technological platforms including internet of things (IoT), artificial intelligence (AI), precision medicine, and wearable chemical/biological sensing systems. In this study, a simple and robust prototype of the so-called potentiostat, electrochemical instrumental system, with a wireless data acquisition and user control is demonstrated. With a wide range of potential applications, the developed system can be conveniently customizable to detect chemical of interest in food safety, continuous at-home diagnosis, environmental monitoring, and low-power energy storage. The device is comprised of two major units: a modified front-end sensor (Texas Instrument, LMP91000EVM), and a development board (Espressif, ESP32) implementing with a programmable saw tooth waveform to assess cyclic voltammetry (CV), the most common electrochemical measurement with the three-electrode configuration, namely working electrode, reference electrode and auxiliary electrode. In particular, the prototype shows a good agreement of CV in a standard electron transfer experiment by monitoring the interchange state of Fe2+ and Fe3+ ion in ferricyanide solution with potassium chloride supported, in comparison to that of the commercial potentiostat. Furthermore, the effects of different scan rate (0.05 to 0.15 V/s) and different ferricyanide concentrations from 1 to 7.5 millimolar are also evaluated to quantify sensing performance. Based on the obtained results, the calibration curve of anodic peak and cathodic peak current are linearly correlated with R2 of 0.9987 and 0.9990, respectively, providing a cost-effective (less than USD 80) and portable solution to the future integration of sensing technology.
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Development of non-enzymatic N-doped graphene supported cobalt/iron amperometric based sensor for glucose detection in urine
(2019-01-24)
Janyasupab, Metini
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Promptmas, Chamras
We presented a cost-effective design of electrochemical based biosensor for non-enzymatic glucose detection in urine. By incorporating low-cost, non-precious cobalt (Co)/iron (Fe) metals, the sensor was employed onto the three-electrode system for quantifying glucose level from 0 to 3.25 mM in artificial urine medium and clinical simulated urine solution, namely, Surine. In particular, the fabricated CoFe nanoparticles on N-doped graphene (NG) biosensor was assessed electrochemical performances by cyclic voltammetry and amperometry at applied potential of +0.90 V versus Ag/AgCl, in comparison with that of CoFe on carbon supported. Based on the results, it was found that two processes of catalytic oxidation and oxide depletion are involved in glucose detection. More importantly, the as-prepared biosensor exhibited an outstanding sensitivity of 476.67 µA.cm-2.mM-1 with R2 of 0.9974 in Surine. Furthermore, the low limit of detection was estimated to be 37.7 µM (signal-to-noise ratio of 3) with an excellent anti-interference property toward ascorbic acid, uric acid, and chlorine ions, providing a promising advancement for future glucose measurement in urine, applicable for sustainable diabetic prognosis and management.

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