Label-free electrochemical aptasensor for the detection of lysozyme (original) (raw)
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Bioelectrochemistry, 2015
This work presents a comparison of two different aptamers (COX and TRAN) for the detection of the ubiquitous protein lysozyme using aptamer-based biosensors. The detection is based on the specific recognition by the aptamer immobilized on screen printed carbon electrodes (SPCEs) via diazonium coupling reaction. The quantitative detection of lysozyme protein was achieved by electrochemical impedance spectroscopy (EIS). Very good linear ranges and detection limits for the lysozyme detection were obtained, from 0.025 to 1 µM and 725nM using aptamer COX and from 0.025 to 1 µM and 31.7nM using aptamer TRAN. The obtained results showed that the developed aptasensors exhibit good specificity, stability and reproducibility for lysozyme detection. The aptasensors were also tested in wine samples; very good recovery rates were obtained in the range from 96.4 to 102% for lysozyme detection. The recovery rates confirm the reliability and suitability of the developed method in wine matrix. The developed method could be a useful and promising platform for detection of lysozyme in different applications.
Aptamer-Based Electrochemical Sensing of Lysozyme
Chemosensors, 2016
Protein analysis and quantification are required daily by thousands of laboratories worldwide for activities ranging from protein characterization to clinical diagnostics. Multiple factors have to be considered when selecting the best detection and quantification assay, including the amount of protein available, its concentration, the presence of interfering molecules, as well as costs and rapidity. This is also the case for lysozyme, a 14.3-kDa protein ubiquitously present in many organisms, that has been identified with a variety of functions: antibacterial activity, a biomarker of several serious medical conditions, a potential allergen in foods or a model of amyloid-type protein aggregation. Since the design of the first lysozyme aptamer in 2001, lysozyme became one of the most intensively-investigated biological target analytes for the design of novel biosensing concepts, particularly with regards to electrochemical aptasensors. In this review, we discuss the state of the art of aptamer-based electrochemical sensing of lysozyme, with emphasis on sensing in serum and real samples.
Analytical Biochemistry, 2012
We report on the direct electrochemical detection of aptamer-protein interactions, namely between a DNA aptamer and lysozyme (LYS) based on electrochemical impedance spectroscopy (EIS) technique. First, the affinity of the aptamer to LYS and control proteins was presented by using filter retention assay. An amino-modified version of the DNA aptamer-recognizing lysozyme was covalently immobilized on the surface of multiwalled carbon nanotube-modified screen-printed electrodes (MWCNT-SPEs), which were employed for measurements and have improved properties compared with bare SPEs. This carbon nanotube setup enabled the reliable monitoring of the interaction of lysozyme with its cognate aptamer by EIS transduction of the resistance to charge transfer (R ct ) in the presence of 2.5 mM ½FeðCNÞ 6 3À=4À . This assay system provides a means for the label-free, concentration-dependent, and selective detection of lysozyme with an observed detection limit of 12.09 lg/ml (equal to 862 nM).
Label-Free Aptasensor for Lysozyme Detection Using Electrochemical Impedance Spectroscopy
Proceedings, 2017
This research develops a label-free aptamer biosensor (aptasensor) based on graphite-epoxy composite electrodes (GECs) for the detection of lysozyme protein using Electrochemical Impedance Spectroscopy (EIS) technique. The chosen immobilization technique was based on covalent bonding using carbodiimide chemistry; for this purpose, carboxylic moieties were first generated on the graphite by electrochemical grafting. The detection was performed using [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− as redox probe. After recording the frequency response, values were fitted to its electric model using the principle of equivalent circuits. The aptasensor showed a linear response up to 5 µM for lysozyme and a limit of detection of 1.67 µM. The sensitivity of the established method was 0.090 µM −1 in relative charge transfer resistance values. The interference response by main proteins, such as bovine serum albumin and cytochrome c, has been also characterized. To finally verify the performance of the developed aptasensor, it was applied to wine analysis.
Electrochemical Aptasensors for Biological and Chemical Analyte Detection
Electroanalysis, 2020
Aptamers are short length, single-stranded DNA or RNA affinity molecules which interact with any desired targets such as biomarkers, cells, biological molecules, drugs or chemicals with high sensitivity. They have been extensively employed for medical applications due to having more advantages than the antibodies such as easier preparation and modification, higher stability, lower batch-to-batch variability and cost. Moreover, aptamers can be easily integrated efficiently with sensors, biosensors, actuators and other devices. In this review article, different applications of aptamers for biological and chemical molecules detection within the scope of electrochemical methods were presented with recent studies. In addition, the present status and future perspectives for highly-effective aptasensors for specific and selective analyte detection were discussed. As in stated throughout the review, combining of extraordinary properties of aptamers with the electrochemical-based biosensors could have improved the sensitivity of the assay and reduced limit of detection.
Electrochemical Aptasensors - Recent Achievements and Perspectives
Electroanalysis, 2009
This article reviews recent achievements in developing aptamer-based electrochemical biosensors (electrochemical aptasensors). Aptamers are single stranded DNA or RNA molecules with high specificity to various ligands. Their specificity is comparable and in certain cases even higher than those of antibodies. In contrast to antibodies, aptamers are prepared by an in vitro selection procedure developed simultaneously in the early 1990s by L. Gold and A. Ellington. Due to their stability and the possibility of chemical modification aptamers can be immobilized on various supports and serve as artificial receptors in biosensors. The first aptasensors developed in the second half of 1990s were based on optical detection. However, in early 2000 substantial interest arose to the development of electrochemical aptasensors. It has been shown that due to their simplicity and fast response they represent an excellent tool in practical applications. The main focus of this review is to discuss the configuration of aptamers and electrochemical methods for detecting aptamers -analyte interactions. We will also provide a brief history of aptamer development, along with molecular structure and methods of aptamer engineering. Methods for immobilizing aptamers onto a solid support are also discussed.
Sensors
Aptamers are synthetic bio-receptors of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) origin selected by the systematic evolution of ligands (SELEX) process that bind a broad range of target analytes with high affinity and specificity. So far, electrochemical biosensors have come up as a simple and sensitive method to utilize aptamers as a bio-recognition element. Numerous aptamer based sensors have been developed for clinical diagnostics, food, and environmental monitoring and several other applications are under development. Aptasensors are capable of extending the limits of current analytical techniques in clinical diagnostics, food, and environmental sample analysis. However, the potential applications of aptamer based electrochemical biosensors are unlimited; current applications are observed in the areas of food toxins, clinical biomarkers, and pesticide detection. This review attempts to enumerate the most representative examples of research progress in aptamer based ...
Here, we describe the fabrication of an electrochemical immunoglobulin E (IgE) aptasensor using enzyme-linked aptamer in the sandwich assay method and thionine as redox probe. In this protocol, 50-amine-terminated IgE aptamer and thionine were covalently attached on glassy carbon electrode modified with carbon nanotubes/ionic liquid/chitosan nanocomposite. Furthermore, another IgE aptamer was modified with biotin and enzyme horseradish peroxidase (HRP), which attached to the aptamer via biotin–streptavidin interaction. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry were performed at each stage of the chemical modification process to confirm the resulting surface changes. The presence of IgE induces the formation of a double aptamer sandwich structure on the electrode, and the electrocatalytic reduction current of thionine in the presence of hydrogen peroxide was measured as the sensor response. Under optimized conditions and using differential pulse voltammetry as the measuring technique, the proposed aptasensor showed a low detection limit (6 pM) and high sensitivity (1.88 lA nM1). This aptasensor also exhibited good stability and high selectivity for IgE detection without an interfering effect of some other proteins such as bovine serum albumin (BSA) and lysozyme. The application of the aptasensor for IgE detection in human serum sample was also investigated. The proposed protocol is quite promising as an alternative sandwich approach for various protein assays.
A simple, sensitive and label-free aptamer-based biosensor for the detection of human immunoglobulin E (IgE) is developed using the electrochemical transduction method. A special immobilization interface consisting of multiwalled carbon nanotubes/ionic liquid/chitosan nanocomposite (MWCNTs/IL/Chit) is utilized to improve the conductivity and performance characteristics of the biosensor as well as to increase the loading amount of aptamer DNA sequence. A 5’-amino-terminated aptamer is covalently attached onto MWCNTs/IL/Chit modified glassy carbon (GC) electrode via a linker of glutaraldehyde (GA). Methylene blue (MB) is used as an electrochemical indicator which is intercalated into the aptamer through the specific interaction with its guanine bases. In the absence of IgE, MB bound to the aptamer produces a strong differential pulse voltammetric (DPV) signal. But when IgE exists, the intercalated MB releases from the aptamer, resulting an obviously decreased DPV signal. This phenomenon can be applied for human IgE detection. The peak current of MB linearly decreases with the concentration of IgE over a range of 0.5–30 nM with a detection limit of 37 pM. By using Bovine serum albumin (BSA) and lysozyme, the excellent specificity of this sensing system for the detection of IgE is also demonstrated. Finally, the proposed aptasensor is successfully used to IgE analysis in human serum sample. The obtained result is well agreed with the value obtained by the standard ELISA method. The herein described approach is expected to promote the exploitation of aptamer-based biosensors for protein assays in biochemical and biomedical studies