Label-free impedimetric aptasensor for lysozyme detection based on carbon nanotube-modified screen-printed electrodes (original) (raw)
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Design and testing of aptamer-based electrochemical biosensors for proteins and small molecules
Bioelectrochemistry, 2009
The fabrication of aptamer-based electrochemical biosensors as an emerging technology has made the detection of small and macromolecular analytes easier, faster, and more suited for the ongoing transition from fundamental analytical science to the early detection of protein biomarkers. Aptamers are synthetic oligonucleotides that have undergone iterative rounds of in vitro selection for binding with high affinity to specific analytes of choice; a sensitive yet simple method to utilize aptamers as recognition entities for the development of biosensors is to transduce the signal electrochemically. In this review article, we attempt to summarize the state-of-the-art research progresses that have been published in recent years; in particular, we focus on the electrochemical biosensors that incorporate aptamers for sensing small organic molecules and proteins. Based on differences in the design of the DNA/RNA-modified electrodes, we classify aptamer-based electrochemical sensors into three categories, for which the analyte detection relies on: (a) configurational change, i.e., the analyte binding induces either an assembly or dissociation of the sensor construct; (b) conformational change, i.e., the analyte binding induces an alteration in the conformation (folding) of the surface immobilized aptamer strands; and (c) conductivity change, i.e., the analyte binding "switches on" the conductivity of the surface-bound aptamer-DNA constructs. In each section, we will discuss the performance of these novel biosensors with representative examples reported in recent literature.
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.
Electrochemical aptamer-based biosensors as potential tools for clinical diagnostics
Analytical Methods, 2016
Aptamers are single-stranded DNA and RNA sequences that belong to the group of "functional nucleic acids", which exhibit both catalytic and receptor properties. Aptamers change their spatial conformation upon binding to a target analyte, and so far more than 200 sequences selective for large variety of molecules such as metal ions, organic dyes, proteins and bacteria cells have been identified. Aptamers can be applied in several fields including diagnostics, therapy and as the recognition layers for biosensors, which is one of the most promising areas. The utilization of aptamers as receptor elements in electrochemical assays requires not only the choice of an appropriate immobilization method with respect to the detected target, but also experimental conditions including the manner of analytical signal generation. The latter issue might affect the efficiency of binding between the aptamer-modified surface and analyte, and consequently the sensitivity of target molecule quantification. Herein, a review of electrochemical aptasensors dedicated to the determination of target analytes crucial in clinical diagnostics developed during the past 10 years is presented. It contains a short characterization of aptamers and their application as sensing layers in electrochemical assays, which is followed by a description of the examples of the use of aptasensors.
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.
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.
Aptamers based electrochemical biosensor for protein detection using carbon nanotubes platforms
Biosensors & Bioelectronics, 2010
A label-free bioelectronic detection of aptamer–thrombin interaction based on electrochemical impedance spectroscopy (EIS) technique is reported. Multiwalled carbon nanotubes (MWCNTs) were used as modifiers of screen-printed carbon electrotransducers (SPCEs), showing improved characteristics compared to the bare SPCEs. 5′amino linked aptamer sequence was immobilized onto the modified SPCEs and then the binding of thrombin to aptamer sequence was monitored by EIS transduction of the resistance to charge transfer (Rct) in the presence of 5 mM [Fe(CN)6]3−/4−, obtaining a detection limit of 105 pM. This study represents an alternative electrochemical biosensor for the detection of proteins with interest for future applications.
Adapting Selected Nucleic Acid Ligands (Aptamers) to Biosensors
Analytical Chemistry, 1998
A flexible biosensor has been developed that utilizes immobilized nucleic acid aptamers to specifically detect free nonlabeled non-nucleic acid targets such as proteins. In a model system, an anti-thrombin DNA aptamer was fluorescently labeled and covalently attached to a glass support. Thrombin in solution was selectively detected by following changes in the evanescent-wave-induced fluorescence anisotropy of the immobilized aptamer. The new biosensor can detect as little as 0.7 amol of thrombin in a 140-pL interrogated volume, has a dynamic range of 3 orders of magnitude, has an inter-sensing-element measurement precision of better than 4% RSD over the range 0-200 nM, and requires less than 10 min for sample analysis. The aptamer-sensor format is generalizable and should allow sensitive, selective, and fast determination of a wide range of analytes.
Label-free electrochemical aptasensor for the detection of lysozyme
Talanta, 2009
This work reports the advantages of a label free electrochemical aptasensor for the detection of lysozyme. The biorecognition platform was obtained by the adsorption of the aptamer on the surface of a carbon paste electrode (CPE) previously blocked with mouse immunoglobulin under controlled-potential conditions. The recognition event was detected from the decrease in the guanine and adenine electro-oxidation signals produced as a consequence of the molecular interaction between the aptamer and lysozyme. The biosensing platform demonstrated to be highly selective even in the presence of large excess (9-fold) of bovine serum albumin, cytochrome C and myoglobin. The reproducibility for 10 repetitive determinations of 10.0 mg L −1 lysozyme solution was 5.1% and 6.8% for guanine and adenine electro-oxidation signals, respectively. The detection limits of the aptasensor were 36.0 nmol L −1 (if considering guanine signal) and 18.0 nmol L −1 (if taking adenine oxidation current). This new sensing approach represents an interesting and promising alternative for the electrochemical quantification of lysozyme.
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.