Affinity Biosensors for Detection Immunoglobulin E and Cellular Prions. Antibodies vs. DNA Aptamers

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimImmunosensors for detection of proteins are of high importance for medical diagnostics. There exists continuous effort in their development using new methods of antibody immobilizations at the various surfaces including novel nanomaterials, such as carbon nanotubes, graphene, dendrimers and combination of these materials with nanoparticles of various origin. At the same time as an alternative to antibodies DNA or RNA aptamers are considered as novel receptors during last 2 decades. In contrast with antibodies aptamers are more flexible and stable, allowing various chemical modification without lost of their sensitivity. This review compares the properties of existing immuno- and aptasensors for detection human immunoglobulin E (IgE) and cellular prions (PrPC). It has been shown, that both immuno- and aptasensors are of comparable sensitivity and selectivity that depends on the method of receptor immobilization and detection

Layer-by-layer polyelectrolyte assembles involving DNA as a platform for DNA sensors

The development of DNA-sensors has become significantly important in the past decades due to prospects of application in medicine, biotechnology and exploring fundamental problems related to cell biology and DNA functioning. Layer-by-layer (LbL) immobilization provides unique approach to the implementation of DNA into the surface sensing layers, a crucial step of DNA-sensor development. The review considers main aspects of LbL assembling in DNA-sensor development and application for the detection of complementary oligonucleotides and DNA damage assessment. Besides, electrostatic assembling due to stepwise accumulation of oppositely charged layers, various combinations of covalent binding and affine immobilization are also considered. The characteristics of DNA containing multilayers onto the solid support and the effect of the immobilization techniques and layers assembled on the performance of appropriate DNAsensors are summarized for different target analytes. © 2011 Bentham Science Publishers Ltd

Electrochemical DNA sensors and aptasensors based on electropolymerized materials and polyelectrolyte complexes

© 2015 Elsevier B.V. DNA sensors based on oligonucleotides and aptamers immobilized using electropolymerization and layer-by-layer assembling are reviewed. The conditions of electropolymerization and the role of electrosynthesized layers are considered for polyaniline, polypyrrole, polythiophene, polyphenazines and their derivatives with particular attention to immobilization of bioreceptors and signal detection principles. The performance of DNA sensors for hybridization detection and for the determination of low-molecular intercalators and DNA damaging factors is reviewed. Besides, the composition of polyelectrolyte complexes utilizing DNA receptors are considered depending on the analyte nature and functions of polyionic components and auxiliary reagents used for surface layer coatings

Electrochemical DNA sensors and aptasensors based on electropolymerized materials and polyelectrolyte complexes

© 2016 Elsevier B.V.DNA sensors based on oligonucleotides and aptamers immobilized using electropolymerization and layer-by-layer assembling are reviewed. The conditions of electropolymerization and the role of electrosynthesized layers are considered for polyaniline, polypyrrole, polythiophene, polyphenazines and their derivatives with particular attention to immobilization of bioreceptors and signal detection principles. The performance of DNA sensors for hybridization detection and for the determination of low-molecular intercalators and DNA damaging factors is reviewed. Besides, the composition of polyelectrolyte complexes utilizing DNA receptors are considered depending on the analyte nature and functions of polyionic components and auxiliary reagents used for surface layer coatings

Impedimetric determination of kanamycin in milk with aptasensor based on carbon black‐oligolactide composite

The determination of antibiotics in food is important due to their negative effect on human health related to antimicrobial resistance problem, renal toxicity, and allergic effects. We propose an impedimetric aptasensor for the determination of kanamycin A (KANA), which was assembled on the glassy carbon electrode by the deposition of carbon black in a chitosan matrix followed by carbodiimide binding of aminated aptamer mixed with oligolactide derivative of thiacalix[4]arene in a cone configuration. The assembling was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. In the presence of the KANA, the charge transfer resistance of the inner interface surprisingly decreased with the analyte concentration within 0.7 and 50 nM (limit of detection 0.3 nM). This was attributed to the partial shielding of the negative charge of the aptamer and of its support, a highly porous 3D structure of the surface layer caused by a macrocyclic core of the carrier. The use of electrostatic assembling in the presence of cationic polyelectrolyte decreased tenfold the detectable concentration of KANA. The aptasensor was successfully tested in the determination of KANA in spiked milk and yogurt with recoveries within 95% and 115%. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 16‐13‐000051/0419/20Funding: I.S. acknowledges financial support from the Russian Science Foundation (grant no. 16‐13‐00005) in the synthesis and application in the biosensor platform of the oligolactides bearing thiacalix[4]arene fragments. T.H. acknowledges funding from the European Union’s Horizon 2020 Research and Innovation Program underthe Marie Sklodowska‐Curie grant agreement no. 690898 and from the Science Grant Agency VEGA, project No.1/0419/20

Electrochemical Aptasensor Based on Poly(Neutral Red) and Carboxylated Pillar[5]arene for Sensitive Determination of Aflatoxin M1

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Aptasensor for highly sensitive determination of aflatoxin M1 (AFM1) was developed on the base of glassy carbon electrode (GCE) covered with polymeric Neutral red (NR) dye obtained by electropolymerization in the presence of polycarboxylated pillar[5]arene derivative. Aptamer against AFM1 and NR label were then covalently linked to the carboxylic groups of the carrier by carbodiimide binding. At presence of AFM1 the cathodic peak current related to the NR conversion decreases. AFM1 induced also an increase of the charge transfer resistance measured by electrochemical impedance spectroscopy. In optimal conditions, this make it possible to determine from 5 to 120 ng/L AFM1 in standard solutions with limit of detection (LOD) of 0.5 ng/L. The aptasensor was validated on the spiked samples of cow and sheep milk as well as in kefir after their methanol dilution. Reliable detection of the 40–160 ng/kg of mycotoxins was reached. This is below limited threshold value (50 μg/kg) established in EC

Polyphenothiazine modified electrochemical aptasensor for detection of human α-thrombin

QCM aptasensor for detection human thrombin has been developed on the base of polymeric forms of phenothiazine dyes, Methylene Blue and Methylene Green. Electrostatic accumulation of the analyte in the polyphenothiazine layer made it possible to increase the sensitivity of QCM detection of thrombin in comparison with bare gold electrodes coated with avidin or neutravidin. The influence of nonspecific binding of human serum albumin and the optimal composition of the surface layers were determined. The aptasensors developed make it possible to detect 10-100 nM of thrombin. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA

Recent Achievements in Electrochemical and Surface Plasmon Resonance Aptasensors for Mycotoxins Detection

Mycotoxins are secondary metabolites of fungi that contaminate agriculture products. Their release in the environment can cause severe damage to human health. Aptasensors are compact analytical devices that are intended for the fast and reliable detection of various species able to specifically interact with aptamers attached to the transducer surface. In this review, assembly of electrochemical and surface plasmon resonance (SPR) aptasensors are considered with emphasis on the mechanism of signal generation. Moreover, the properties of mycotoxins and the aptamers selected for their recognition are briefly considered. The analytical performance of bio-sensors developed within last three years makes it possible to determine mycotoxin residues in water and agriculture/food products on the levels below their maximal admissible concentrations. Requirements for the development of sample treatment and future trends in aptasensors are also discussed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: T.K. acknowledges funding by the subsidy allocated to Kazan Federal University for the state assignment in the sphere of scientific activities (grant No 0671–2020−0063). T.H. acknowledges funding from the Science Grant Agency VEGA, project No.: 1/0419/20

Electrochemical aptasensors based on hybrid metal-organic frameworks

Metal-organic frameworks (MOFs) offer a unique variety of properties and morphology of the structure that make it possible to extend the performance of existing and design new electrochemical biosensors. High porosity, variable size and morphology, compatibility with common components of electrochemical sensors, and easy combination with bioreceptors make MOFs very attractive for application in the assembly of electrochemical aptasensors. In this review, the progress in the synthesis and application of the MOFs in electrochemical aptasensors are considered with an emphasis on the role of the MOF materials in aptamer immobilization and signal generation. The literature information of the use of MOFs in electrochemical aptasensors is classified in accordance with the nature and role of MOFs and a signal mode. In conclusion, future trends in the application of MOFs in electrochemical aptasensors are briefly discussed. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.A.P. acknowledges support of the Russian Science Foundation (grant No 17-73-20024) in part related to the analysis of the reaction conditions and operation of the MOF aptasensors. T.H. acknowledges funding from the Science Grant Agency VEGA, project No.: 1/0419/20

Advances in lipid film based biosensors

© 2016 Elsevier B.V.Since first report on formation stable free standing bilayer lipid membranes (BLM) in 1962 by Mueller et al. [1] these systems became very popular in modeling various membrane processes at molecular level, such as ionic transport, ligand-receptor interactions or lipid-protein interactions. Despite of advantage of BLM in respect of variation in lipid composition and their modifications by receptors and proteins, the work with these systems was rather difficult due to their limited stability. The situation has been considerably improved by introduction of supported bilayer lipid membranes (sBLM) in 1980 by Thompson et al. [2] for possible applications in biosensors. Recent advances in stabilization of supported lipid membranes, appearance of novel nanomaterials such as carbon nanotubes has increased the number of publications on this topic. This review summarizes latest achievements in the field of biosensors utilizing sBLMs