scholarly journals An Innovative Nanobody-Based High-Biocompatibility Gold Interdigitated Microelectrode Electrochemical Bioimpedance Sensor for the Ultrasensitive Detection of Difenacoum in Human Serum

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3930
Author(s):  
Liuchuan Guo ◽  
Sihan Wang ◽  
Zhiwei He ◽  
Jing Zhang ◽  
Xiaoli Zhu ◽  
...  
Keyword(s):  
Human Serum ◽  
Detection Method ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Intentional Ingestion ◽  
Accuracy And Precision ◽  
Highly Sensitive ◽  
Interdigitated Microelectrode ◽  
Polycrystalline Gold

Difenacoum (DIF) is one of the most widely used anticoagulant rodenticides. However, accidental or intentional ingestion of DIF seriously threatens humans and other non-target species. Therefore, a rapid and sensitive detection method to quantify DIF is urgently needed. In this study, one anti-DIF nanobody (Nb) was assembled on the surface of a gold interdigitated microelectrode (IDME) using an Au–S bond to fabricate a bioimpedance sensor. To improve the immobilization amount of Nbs on the electrode, a polycrystalline gold IDME was prepared to provide a larger surface and better biocompatibility. Thus, a novel and ultrasensitive bioimpedance sensor based on electrochemical impedance spectroscopy (EIS) was designed for the determination of DIF, and it displayed good reproducibility and stability in human serum. The proposed bioimpedance sensor displayed a wide working range, between 0.1–1000 pg/mL, with a limit of detection (LOD) of 0.1 pg/mL of DIF. This method exhibited excellent performance, good sensitivity, and reproducibility and achieved the highest sensitivity of all currently existing methods used to quantify DIF. The highly sensitive DIF detection of this proposed bioimpedance sensor indicates its potential as an efficacious approach for DIF monitoring in human serum with high accuracy and precision.

scholarly journals Determination of the Anti-Osteoporosis Drug Ipriflavone in Pharmaceutical Formulation by Stripping Voltammetric and Chromatographic Methods

2009 ◽  
Vol 92 (3) ◽  
pp. 806-812 ◽  
Author(s):  
Hanaa S El-Desoky ◽  
Amr M Beltagi ◽  
Mohamed M Ghoneim
Keyword(s):  
Double Bond ◽  
Linear Response ◽  
Detection Method ◽  
Limit Of Detection ◽  
Hanging Mercury Drop Electrode ◽  
Analyte Molecule ◽  
Accuracy And Precision ◽  
Prevention And Treatment ◽  
Osteoporosis Drug

Abstract Ipriflavone is a nonhormonal isoflavone derivative currently used as a bone-building agent for prevention and treatment of postmenopausal osteoporosis. Ipriflavone was reduced at the hanging mercury drop electrode in buffers of pH 211 via the consumption of 2 electrons corresponding to the reduction of the C=O double bond in the C 4 position of the analyte molecule. A fully validated square-wave adsorptive cathodic stripping (SW-AdCS) voltammetric method was described for the trace quantification of bulk ipriflavone. A linear response, with concentrations of bulk ipriflavone over the range 5 1094 107 M with a limit of detection of 1.5 109 M bulk ipriflavone, was obtained. Moreover, an LC-UV detection method was also described for determining ipriflavone. The peak area was proportional to the concentration of bulk ipriflavone over the range 1 1071 104 M with a limit of detection of 3 108 M. The described SW-AdCS voltammetric and LC methods were successfully applied for the assay of ipriflavone in iprivone<sup/> tablets without interference from excipients. Accuracy and precision of both methods for determination of ipriflavone in its tablets were studied and discussed.

scholarly journals A Sensitive Aptamer-Based Biosensor for Electrochemical Quantification of PSA as a Specific Diagnostic Marker of Prostate Cancer

2020 ◽  
Vol 23 ◽  
pp. 243-258 ◽  
Author(s):  
Shokoufeh Hassani ◽  
Armin Salek Maghsoudi ◽  
Milad Rezaei Akmal ◽  
Soheila Rahmani Rahmani ◽  
Pouria Sarihi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Specific Antigen ◽  
Differential Pulse ◽  
Label Free ◽  
Serum Samples ◽  
Highly Sensitive ◽  
Set Up

Purpose: The current project aimed to design a simple, highly sensitive, and economical label-free electrochemical aptasensor for determination of prostate-specific antigen (PSA), as the gold standard biomarker for prostate cancer diagnosis. The aptasensor was set up using a screen-printed carbon electrode (SPCE) modified by gold nanoparticles (Au NPs) conjugated to thiolated aptamers. Methods: Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented for electrochemical (EC) characterization of the aptasensor. The determination of PSA was also performed through differential pulse voltammetry (DPV) in [Fe (CN) 6]3-/4- electrolyte solution. Results: The present aptasensor was shown an outstanding linear response in the concentration range of 1 pg/mL - 200 ng/mL with a remarkably lower limit of detection of 0.077 pg/mL. The optimum concentration for PSA separation and the optimum incubation time for antigen-aptamer binding were determined by observing and electing the highest electrochemical responses in a specified time or concentration. Conclusion: According to the results of the specificity tests, the designed aptasensor did not show any significant interactions with other analytes in real samples. Clinical functionality of the aptasensor was appraised in serum samples of healthy individuals and patients examining the PSA level through the fabricated aptasensor and the reference methods. Both methods are comparable in sensitivity. The present fabricated PSA aptasensor with substantial characteristics of ultra-sensitivity and cost-effectiveness can be conventionally built and used for the routine check-up of the men for prostate problems.

Detection of Glucose in Human Serum Based on Silicon Dot Probe

2020 ◽  
Vol 16 (6) ◽  
pp. 744-752
Author(s):  
Kuan Luo ◽  
Xinyu Jiang
Keyword(s):  
Quantum Dots ◽  
Blood Glucose ◽  
Human Serum ◽  
Organic Dyes ◽  
Limit Of Detection ◽  
Fasting Blood Glucose ◽  
Glucose Biosensor ◽  
Metal Nanoclusters ◽  
Glucose Levels ◽  
Highly Sensitive

Background: Diabetes Mellitus (DM) is a major public metabolic disease that influences 366 million people in the world in 2011, and this number is predicted to rise to 552 million in 2030. DM is clinically diagnosed by a fasting blood glucose that is equal or greater than 7 mM. Therefore, the development of effective glucose biosensor has attracted extensive attention worldwide. Fluorescence- based strategies have sparked tremendous interest due to their rapid response, facile operation, and excellent sensitivity. Many fluorescent compounds have been employed for precise analysis of glucose, including quantum dots, noble metal nanoclusters, up-converting nanoparticles, organic dyes, and composite fluorescent microspheres. Silicon dot as promising quantum dots materials have received extensive attention, owing to their distinct advantages such as biocompatibility, low toxicity and high photostability. Methods: MnO2 nanosheets on the Si nanoparticles (NPs) surface serve as a quencher. Si NPs fluorescence can make a recovery by the addition of H2O2, which can reduce MnO2 to Mn2+, and the glucose can thus be monitored based on the enzymatic conversion of glucose by glucose oxidase to generate H2O2. Therefore, the glucose concentration can be derived by recording the fluorescence recovery spectra of the Si NPs. Results: This probe enabled selective detection of glucose with a linear range of 1-100 μg/mL and a limit of detection of 0.98 μg/mL. Compared with the commercial glucometer, this method showed favorable results and convincing reliability. Conclusion: We have developed a novel method based on MnO2 -nanosheet-modified Si NPs for rapid monitoring of blood glucose levels. By combining the highly sensitive H2O2/MnO2 reaction with the excellent photostability of Si NPs, a highly sensitive, selective, and cost-efficient sensing approach for glucose detection has been designed and applied to monitor glucose levels in human serum with satisfactory results.

scholarly journals Immobilization-Free Electrochemical Sensor Coupled with a Graphene-Oxide-Based Aptasensor for Glycated Albumin Detection

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 85
Author(s):  
Wassa Waiwinya ◽  
Thitirat Putnin ◽  
Dechnarong Pimalai ◽  
Wireeya Chawjiraphan ◽  
Nuankanya Sathirapongsasuti ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensor ◽  
Detection Method ◽  
Limit Of Detection ◽  
Glycated Albumin ◽  
Cost Effective ◽  
Logarithmic Scale ◽  
Electrochemical Aptasensor ◽  
Alternative Approach

An immobilization-free electrochemical sensor coupled with a graphene oxide (GO)-based aptasensor was developed for glycated human serum albumin (GHSA) detection. The concentration of GHSA was monitored by measuring the electrochemical response of free GO and aptamer-bound GO in the presence of glycated albumin; their currents served as the analytical signals. The electrochemical aptasensor exhibited good performance with a base-10 logarithmic scale. The calibration curve was achieved in the range of 0.01–50 µg/mL. The limit of detection (LOD) was 8.70 ng/mL. The developed method was considered a one-drop measurement process because a fabrication step and the probe-immobilization process were not required. This simple sensor offers a cost-effective, rapid, and sensitive detection method, and could be an alternative approach for determination of GHSA levels.

scholarly journals Development and Validation of a Rapid RP-HPLC Method for the Estimation of Esmolol Hydrochloride in Bulk and Pharmaceutical Dosage Forms

2010 ◽  
Vol 7 (3) ◽  
pp. 807-812 ◽  
Author(s):  
Vanita Somasekhar ◽  
D. Gowri Sankar
Keyword(s):  
Limit Of Detection ◽  
Hplc Method ◽  
Detector Response ◽  
Reverse Phase Hplc ◽  
Limit Of Quantification ◽  
Pharmaceutical Dosage Forms ◽  
Rp Hplc ◽  
Accuracy And Precision ◽  
Development And Validation

A reverse phase HPLC method is described for the determination of esmolol hydrochloride in bulk and injections. Chromatography was carried on a C18column using a mixture of acetonitrile, 0.05 M sodium acetate buffer and glacial acetic acid (35:65:3 v/v/v) as the mobile phase at a flow rate of 1 mL/min with detection at 275 nm. The retention time of the drug was 4.76 min. The detector response was linear in the concentration of 1-50 μg/mL. The limit of detection and limit of quantification was 0.614 and 1.86 μg/mL respectively. The method was validated by determining its sensitivity, linearity, accuracy and precision. The proposed method is simple, economical, fast, accurate and precise and hence can be applied for routine quality control of esmolol hydrochloride in bulk and injections.

scholarly journals Determination of uric acid in human serum by an enzymatic method using N-methyl-N-(4-aminophenyl)-3-methoxyaniline reagent

2003 ◽  
Vol 68 (8-9) ◽  
pp. 691-698 ◽  
Author(s):  
Milena Jelikic-Stankov ◽  
Predrag Djurdjevic ◽  
Dejan Stankov
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Limit Of Detection ◽  
Ascorbate Oxidase ◽  
Acid Oxidation ◽  
Uric Acid Concentration ◽  
Enzymatic Method ◽  
Limit Of Quantification ◽  
Relative Standard

In this work a new enzymatic method for the determination of uric acid in human serum has been developed. The method is based on the oxidative coupling reaction between the N-methyl-N-(4-aminophenyl)-3-methoxyaniline (NCP) reagent and the hydrogen ? donor reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline (TOOS), in the system involving three enzymes: uricase, peroxidase and ascorbate oxidase. Using this method uric acid could be determined in concentrations up to 1.428 mmol/L, with a relative standard deviation of up to 1.8 %. The effect of the medium pH and the NCP concentration on the linearity of the chromogen absorbance versus the uric acid concentration curve was investigated. The influence of the uricase activity on the maximum rate of uric acid oxidation was also examined. The use of the NCP reagent demonstrated a more precise and more sensitive determination of the uric acid compared to the determination with 4-aminoantipyrine (4-AA) as the coupling regent. The sensitivity of the method determined from the calibration curve was 0.71 absorbance units per mmol/L of uric acid; the limit of detection was LOD = 0.0035 mmol/L and the limit of quantification was LOQ = 0.015 mmol/L of uric acid.

scholarly journals An Electrochemical Sensor Based On Graphite Electrode Modified With Silica Containing 1-N-Propyl-3-Methylimidazolium Species For Determination Of Ascorbic Acid

2019 ◽  
Vol Vol. 14, No.1 ◽  
pp. 5-14 ◽  
Author(s):  
Anastasiya Tkachenko ◽  
Mykyta Onizhuk ◽  
Oleg Tkachenko ◽  
Leliz T. Arenas ◽  
Edilson V. Benvenutt ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Cyclic Voltammetry ◽  
Electrochemical Sensor ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Pharmaceutical Formulations ◽  
Differential Pulse ◽  
Long Term Stability ◽  
Diffusion Limited

In the present study, an electrochemical sensor based on the electrode (SiMImCl/C) consisting of graphite and silica, grafted with 1-n-propyl-3-methylimidazolium chloride was used for ascorbic acid (AA) quantification in pharmaceuticals and food formulations. Cyclic voltammetry and electrochemical impedance spectroscopy were applied for electrochemical characterization of the SiMImCl/C electrode. The cyclic voltammetry study revealed that the oxidation of AA on this electrode is an irreversible process, realized by adsorption and diffusion limited step. The differential pulse voltammetry was applied to develop a procedure for the AA determination. The linear range was found to be 0.3–170 μmol L-1 and the limit of detection – 0.1 μmol L-1. The proposed SiMImCl/C electrode has long term stability and does not show electrochemical activity towards the analytes, which commonly coexist with AA. The sensor was successfully used for quantification of AA in food and pharmaceutical formulations.

scholarly journals Spectrophotometric Determination of Olmutinib in Bulk by Area under Curve and First Order Derivative Methods and its Validation as per ICH guidelines

2019 ◽  
Vol 9 (4-A) ◽  
pp. 349-354
Author(s):  
BALU KHANDARE ◽  
Atish C. Musle ◽  
Sanket S. Arole ◽  
Pravin V. Popalghat
Keyword(s):  
Area Under Curve ◽  
Limit Of Detection ◽  
Order Derivative ◽  
Spectrometric Method ◽  
First Order ◽  
Accuracy And Precision ◽  
Ich Guidelines ◽  
Validation Parameters ◽  
Limit Of Quantitation

Abstract: A simple, precise and economical UV-spectrophotometric method has been developed for the estimation of Olmutinib from bulk. Two methods were developed First method (A) applied was area under curve (AUC) in which the area was integrated in wavelength from 262-272nm. Second method (B) was first order derivative spectrometric method. In this method absorbance at λmin=256.57nm, λmax=282.83nm and zero cross=267.68nm was measured. Calibration curves were plotted for the method by using instrumental response at selected wavelength and concentration of analyte in the solution. In both the methods, linearity was observed in the concentration range of 2-12µg/ml at the λmax=267.68nm. Accuracy and precision studies were carried out and results were satisfactorily obtained. The drug at each of the 80 %, 100 % and 120 % levels showed good recoveries that is in the range of 98.00 to 99.00% for both methods, hence it could be said that the method was accurate. Limit of detection (LOD) and limit of quantitation (LOQ) were determined for the method. The method was validated as per International Conference on Harmonization. All validation parameters were within the acceptable limit. The developed method was successfully applied to estimate the amount of Olmutinib in pharmaceutical formulation.

scholarly journals Highly sensitive dual mode electrochemical platform for microRNA detection

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Pawan Jolly ◽  
Marina R. Batistuti ◽  
Anna Miodek ◽  
Pavel Zhurauski ◽  
Marcelo Mulato ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Dual Mode ◽  
Electrode Surfaces ◽  
Microrna Detection ◽  
Highly Sensitive ◽  
Detection Mode ◽  
Amplification Strategy

Abstract MicroRNAs (miRNAs) play crucial regulatory roles in various human diseases including cancer, making them promising biomarkers. However, given the low levels of miRNAs present in blood, their use as cancer biomarkers requires the development of simple and effective analytical methods. Herein, we report the development of a highly sensitive dual mode electrochemical platform for the detection of microRNAs. The platform was developed using peptide nucleic acids as probes on gold electrode surfaces to capture target miRNAs. A simple amplification strategy using gold nanoparticles has been employed exploiting the inherent charges of the nucleic acids. Electrochemical impedance spectroscopy was used to monitor the changes in capacitance upon any binding event, without the need for any redox markers. By using thiolated ferrocene, a complementary detection mode on the same sensor was developed where the increasing peaks of ferrocene were recorded using square wave voltammetry with increasing miRNA concentration. This dual-mode approach allows detection of miRNA with a limit of detection of 0.37 fM and a wide dynamic range from 1 fM to 100 nM along with clear distinction from mismatched target miRNA sequences. The electrochemical platform developed can be easily expanded to other miRNA/DNA detection along with the development of microarray platforms.

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