Research highlights: aptamers on a chip

Unravelling the potential of magnetic nanoparticles: a comprehensive review of design and applications in analytical chemistry

The study of nanoparticles has emerged as a prominent research field, offering a wide range of applications across various disciplines. With their unique physical and chemical properties within the size range of 1-100 nm, nanoparticles have garnered significant attention. Among them, magnetic nanoparticles (MNPs) exemplify promising super-magnetic characteristics, especially in the 10-20 nm size range, making them ideal for swift responses to applied magnetic fields. In this comprehensive review, we focus on MNPs suitable for analytical purposes. We investigate and classify them based on their analytical applications, synthesis routes, and overall utility, providing a detailed literature summary. By exploring a diverse range of MNPs, this review offers valuable insights into their potential application in various analytical scenarios.

An ultrasensitive aptasensor for Ochratoxin A using hexagonal core/shell upconversion nanoparticles as luminophores

We developed an ultrasensitive luminescence resonance energy transfer (LRET) aptasensor for Ochratoxin A (OTA) detection, using core/shell upconversion nanoparticles (CS-UCNPs) as luminophores. The OTA aptamer was tagged to CS-UCNPs as energy donor and graphene oxide (GO) acted as energy acceptor. The π-π stacking interaction between the aptamer and GO brought CS-UCNPs and GO in close proximity hence initiated the LRET process resulting in quenching of CS-UCNPs luminescence. A linear calibration was obtained between the luminescence intensity and the logarithm of OTA concentration in the range from 0.001ngmL^-1 to 250ngmL^-1, with a detection limit of 0.001ngmL^-1. The aptasensor showed good specificity towards OTA in beer samples. The ultrahigh sensitivity and pronounced robustness in beer sample matrix suggested promising prospect of the aptasensor inpractical applications.

Application of DNA aptamers as sensing layers for detection of carbofuran by electrogenerated chemiluminescence energy transfer

In this study, an electrogenerated chemiluminescence (ECL) sensing platform for carbofuran detection was constructed based on ECL energy transfer (ECRET) and carbon dot (C-dot)-tagged aptamers as the recognition element. Fullerene (C60)-loaded gold nanoparticles (C60-Au) were used as the energy donor, modified on a glassy carbon electrode. C-dot-tagged DNA aptamers were used as the receptor, and ECRET then occurred between C60-Au and C-dots. After accepting the energy, the C-dots acted as a signal indicator and showed decreased signal intensity in the presence of targets, which competitively bound to DNA aptamers and blocked energy transfer. Using this robust, straight-forward strategy, the sensor showed a linear ECL response to carbofuran at concentrations from 2.0 × 10^-11 mol L^-1 to 8.0 × 10^-9 mol L^-1. The detection limit of this assay was shown to be 8.8 × 10^-13 mol L^-1. Thus, the sensing approach described in this study could be adapted for use in the detection of various pesticide residue targets.