Square wave voltammetry is used in this work to detect human islet amyloid polypeptide (hIAPP) by using the oxidized signal of the tyrosine residue in hIAPP. A detection limit of 1×10-6 M for hIAPP has been obtained. A kinetic study of the aggregation process has been carried out according to the relationship between the anodic peak current in the square wave voltammograms of hIAPP and the incu...

We studied a refractive index sensor that consists of two cascaded ring resonators and that works analogously to a Vernier-scale. We implemented it in silicon-on-insulator and experimentally determined its sensitivity to be as high as 2169 nm/RIU in aqueous environment. We derived formulas describing the sensor's operation, and introduced a fitting procedure that allows to accurately detect cha...

* Limit of Blank (LoB), Limit of Detection (LoD), and Limit of Quantitation (LoQ) are terms used to describe the smallest concentration of a measurand that can be reliably measured by an analytical procedure. * LoB is the highest apparent analyte concentration expected to be found when replicates of a blank sample containing no analyte are tested. LoB = mean(blank) + 1.645(SD(blank)). * LoD is ...

In this paper, we report a novel electrochemical method that can be developed as a biosensor for simple and direct determination of α-amylase activity. The method is based on the hydrolysis of maltopentaose, the substrate of the enzyme, which is immobilized on the surface of a gold electrode, and the induced charge changes of the substrate-modified electrode. Specifically, the substrate maltope...

A label-free electrochemical biosensing platform has been developed for the first time using carbon nanotubes for facile detection of malondialdehyde, showing high sensitivity and acceptable selectivity with a low detection limit of 0.047 μmol L(-1) and a linear response ranging from 0.1 to 90 μmol L(-1).

Fourier-transform infrared spectroscopy is a powerful and versatile tool to investigate the structure and dynamics of proteins in solution. The intrinsically low extinction coefficient of the amide I mode, the main structure-related oscillator, together with the high infrared absorptivity of aqueous media, requires that proteins are studied at high concentrations (>10 mg L(-1)). This may repres...

G-quadruplex structure aptamer (PS2.M) can capture acridine orange (AO) from reduced graphene oxide (rGO). When the AO-PS2.M/rGO mixture is incubated with hemin, the specific binding of hemin with PS2.M results in a release of AO from PS2.M and return of AO back to rGO. Based on the quenching of fluorescence, the target hemin was detected sensitively and selectively, giving a detection limit of...

A coumarin TCF-based water-soluble near-infrared fluorescent probe was presented, which could be used for the rapid, colorimetric and ratiometric detection of SO2 derivatives with a detection limit of 0.27 nM. Moreover, this probe could successfully image the analyte in living cells.

In this communication, we develop a novel fluorescent aptasensor for thrombin detection with the use of poly(m-phenylenediamine) (PMPD) rods as an effective sensing platform. This aptasensor exhibits extraordinarily high sensitivity with a detection limit as low as 100 pM and excellent selectivity.