An ultrasensitive fluorescent aptasensor based on truncated aptamer and AGET ATRP for the detection of bisphenol A

An Overview of Aptamer-Based Sensor Platforms for the Detection of Bisphenol-A

Endocrine disruptive compounds are natural or anthropogenic environmental micropollutants that alter the function of the endocrine system ultimately damaging the metabolism. Bisphenol A (BPA) is the most common of these pollutants and it is often used in epoxy coatings and polycarbonates as a plasticizer. Therefore, monitoring BPA levels in different environments is very important and challenging. In recent years, an increasing number of BPA detection methods have been proposed. This article presents a critical review of aptamer-based electrochemical, fluorescence-based, colorimetric, and several other BPA detection platforms published in the last decade. Furthermore, a statistical evaluation has been made using principle component analysis showing analytical performance parameters do not create very different clusters. Comparisons to other BPA detection methods are also presented so that the reader has an overall literature overview.

Photoinduced atom transfer radical polymerization combined with click chemistry for highly sensitive detection of tobacco mosaic virus RNA

An electrochemical biosensor for highly sensitive detection of tobacco mosaic virus (TMV) RNA (tRNA) based on click chemistry and photoinduced atom transfer radical polymerization (photoATRP) is developed for the first time. Herein, tRNA is recognized and captured by hairpin DNA immobilized on the gold electrode surface by Au-S self-assembly. Propyl 2-bromoisobutyrate (PBIB), a photoATRP initiator containing an alkyne group, is conjugated to the azide group of hairpin DNA via a Cu(I)-catalyzed azidoalkyl cyclization reaction (CuAAC). Under the irradiation of 470 nm blue light, photoATRP is activated by the photoredox catalyst (eosin Y, EY), resulting in the formation of a large number of electroactive probes (ferrocenylmethyl methacrylate, FMMA), which significantly amplifies the signal. Under the optimal experimental parameters, the strategy has a wide linear detection (0.1 pM-10 nM) (R² = 0.995) with a limit of detection (LOD) as low as 3.5 fM. In addition, the biosensor also exhibited good selectivity for mismatched bases, excellent stability and reproducibility. Moreover, satisfactory result was achieved when the biosensor was applied to the detection of tRNA from healthy rehmannia total RNA extracts, which demonstrates the great potential of the method in the practical detection of TMV.

Colorimetric Aptasensor for Testosterone Detection Based on Aggregation of Gold Nanoparticles Induced by Cationic Surfactant

This paper proposes a colorimetric aptasensor for the detection of testosterone (TES) in environmental water, using TES-specific aptamer (apT5) as a sensing probe, gold nanoparticles (AuNPs) as indicator, and hexadecyltrimethylammonium bromide (CTAB) as inducer, respectively. Based on competition between TES and CTAB for apT5, the aptamer can form an aptamer–TES complex, leaving CTAB free to aggregate AuNPs in the presence of TES. Dispersed and aggregated AuNPs have different absorption wavelengths and the signal of absorption intensity is associated with the concentration of TES, so TES can be detected quantitatively based on the signal absorption intensity. This sensitive aptasensor for TES detection has a wide linear range (R=0.998) from 1.91–800nM and a limit of detection (LOD) of 1.91nM. In addition, this aptasensor has high selectivity over some interferents. The method detects TES in tap water samples with recoveries in the range of 98.9–102.6% (RSD ≤ 7.35%). This biosensor presents a good and potential application to rapidly detect TES in actual environmental water samples.