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Correction for 'The presence of a 5'-abasic lesion enhances discrimination of single nucleotide polymorphisms while inducing an isothermal ligase chain reaction' by Abu Kausar et al., Analyst, 2016, 141, 4272-4277.
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Lesion-induced DNA amplification (LIDA) has been employed in the detection of single nucleotide polymorphisms (SNPs). Due to the presence of the proximal abasic lesion, T4 DNA ligase exhibits greater intolerance to basepair mismatches when compared with mismatch ligation in the absence of the abasic lesion. Moreover the presence of the abasic group also results in an isothermal ligase chain reaction enabling SNP detection with great discrimination and sensitivity. Specifically, at forty minutes, the ratio of amplified product from the matched and mismatched initiated reactions are 7-12 depending on the mismatch. The ease of implementation of our method is demonstrated by real-time analysis of DNA amplification using a fluorescent plate reader.
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Gold nanoparticles have been widely utilized to achieve colorimetric detection for various diagnostic applications. One of the most frequently used methods for DNA detection involves the aggregation of DNA-modified gold nanoparticles driven by target DNA hybridization. This process, however, is intrinsically slow, limiting its use in rapid diagnostics. Here we take advantage of the reverse process: the disassembly of preformed aggregates triggered by the addition of target DNA via a strand displacement mechanism. A systematic study of the dependence of the disassembly rate on temperature, with and without toeholds, has delivered a system that produces an extremely rapid colorimetric response. Furthermore, using an optimal toehold length of 5 nucleotides, target triggered disassembly is rapid over a wide range of ambient temperatures. Using this overhang system, simple visualization of low picomole amounts of target DNA is possible within 10 min at room temperature.
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ADN/análisis , Oro/química , Nanopartículas del Metal/química , Cinética , Desnaturalización de Ácido Nucleico , Hibridación de Ácido Nucleico , TemperaturaRESUMEN
The concept of optical antennas in physical optics is still evolving. Like the antennas used in the radio frequency (RF) regime, the aspiration of optical antennas is to localize the free propagating radiation energy, and vice versa. For this purpose, optical antennas utilize the distinctive properties of metal nanostructures, which are strong plasmonic coupling elements at the optical regime. The concept of optical antennas is being advanced technologically and they are projected to be substitute devices for detection in the millimeter, infrared, and visible regimes. At present, their potential benefits in light detection, which include polarization dependency, tunability, and quick response times have been successfully demonstrated. Optical antennas also can be seen as directionally responsive elements for point detectors. This review provides an overview of the historical background of the topic, along with the basic concepts and parameters of optical antennas. One of the major parts of this review covers the use of optical antennas in biosensing, presenting biosensing applications with a broad description using different types of data. We have also mentioned the basic challenges in the path of the universal use of optical biosensors, where we have also discussed some legal matters.
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Técnicas Biosensibles/métodos , Óptica y Fotónica/métodos , Humanos , Nanoestructuras/efectos adversos , NanotecnologíaRESUMEN
You spin me round: Using a destabilizing abasic site and high concentration of ligase, rapid DNA self-replication in an isothermal ligase chain reaction (LCR) was produced. Both destabilization and rapid ligation are essential for proper LCR replication. This method also provides insight into prebiotic nucleotide replication and is a potential amplification method for biodiagnostics.
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Replicación del ADN , ADN/química , Reacción en Cadena de la Ligasa/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Oligonucleótidos/química , Catálisis , ADN/biosíntesis , ADN/síntesis química , HumanosRESUMEN
In this paper the photocontrolled manipulation of solid materials on the surface of a liquid crystalline thin film is described. Three different types of films namely cholesteric liquid crystal (ChLC), compensated nematic liquid crystal (NLC) and nematic LC were used. The rotational and translational manipulation of the microscale solid object was induced by irradiation of light and mode of manipulation (either translational or rotational) was changed by changing the isomer of the azobenzene compound used to make the film. Rotational motion of the object was observed on the ChLC and compensated NLC films containing chirally pure azobenzene compound. The direction of rotational motion was controlled either by changing the optical isomer of the chiral azobenzene or by changing the irradiating light (from ultraviolet to visible). When racemic mixture of the chiral azobenzene compound was used, a translational motion of the object was observed. Even though the direction of the translational motion can be controlled by controlling irradiation position, more facile and precise manipulation of the objects was possible by spatially controlled irradiation of Ar(+) laser and diode UV laser.
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On the move: Irradiation of azobenzene-doped liquid crystalline films with UV/Vis light results in the photocontrolled translational motion of microscale solid object on the surface, which occurs through cis-trans isomerization of the azobenzene unit. Irradiation with an Ar(+) laser (488 nm) resulted in precise control of the translational motion so that the particle always moved away from the irradiation position (see picture).