We examine through analytical calculations and finite element simulations how the detection efficiency of disk and wire-like biosensors in unmixed fluids varies with size from the micrometer to nanometer scales. Specifically, we determine the total flux of DNA-like analyte molecules on a sensor as a function of time and flow rate for a sensor incorporated into a microfluidic system. In all case...

We demonstrate a composite nanomaterial, termed an aptamer nano-flare, that can directly quantify an intracellular analyte in a living cell. Aptamer nano-flares consist of a gold nanoparticle core functionalized with a dense monolayer of nucleic acid aptamers with a high affinity for adenosine triphosphate (ATP). The probes bind selectively to target molecules and release fluorescent reporters ...

A new immunometric two-site sandwich assay is introduced, in which a label-scavenging binding partner is added to the sample in addition to the analyte-binding partner. The scavenger binding partner binds excess label antibody, giving a signal proportional to the amount of excess label antibody in the sample solution. A set of two calibration curves is obtained from the two binding partners sim...

We developed a capillary zone electrophoresis method with indirect UV detection for determination of ammonium cations and alkali and alkaline earth metal cations in jellyfish. As the background electrolyte, a mixture of N-methylbenzylamine, citrate, and 18-crown-6 was used for the complete separation of all analyte cations. The limits of detection were 0.13 - 0.34 mg l(-1) at a signal-to-noise ...

We report a sensitive assay method for homogeneous thrombin detection. The method is based on lanthanide chelate complementation, where the luminescent complex is split into two separate label moieties, which are intrinsically non-luminescent. A luminescent mixed chelate complex is formed only when the label moieties are brought into close proximity directed by two separate binding events of ap...

We introduce a mechanism for ion sensing by MRI in which analytes compete with paramagnetic ions for binding to polydentate chelating agents. Displacement of the paramagnetic ions results in alteration of solvent interaction parameters and consequent changes in relaxivity and MRI contrast. The MRI changes can be tuned by the choice of chelator. As an example, we show that calcium-dependent disp...

Newton AJ, Wall MJ, Richardson MJ. Modeling microelectrode biosensors: free-flow calibration can substantially underestimate tissue concentrations. J Neurophysiol 117: 937–949, 2017. First published December 2, 2016; doi:10.1152/jn.00788.2016.—Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, g...

We first report on the development of new microscope means that reduce background contributions in fluorescence fluctuation methods: i) excitation shutter, ii) electronic switches, and iii) early and late time-gating. The elements allow for measuring molecules at low analyte concentrations. We first found conditions of early and late time-gating with time-correlated single-photon counting that ...

Bio-/synthetic hybrid materials have recently received considerable attention owing to their potential biomedical applications. The most reliable way of identifying any biological target is through its genetic code. However, the current commercial DNA microarray requires costly and time-consuming PCR to multiply the number of analyte DNA molecules and label the analyte DNA with a fluorescent dy...

When analyzing an unknown sample, the analytical chemist’s task is to provide an estimate of the concentration of an analyte with acceptable uncertainty (accuracy and precision). Very often, due to the time required to perform a good statistical assessment of instrument performance, the signal-to-noise ratio (S/N) (the ratio of a peak’s height to the variability in the background signal) is use...