Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is used for the multiplex detection and characterization of diverse analytes over a wide mass range directly from tissues. However, analyte coverage with MALDI MSI is typically limited to the more abundant compounds, which have m/z values that are distinct from MALDI matrix-related ions. On-tissue analyte deriva...

Label-free detection of biomolecules using an optical whispering-gallery mode sensor in a microelectrofluidic channel is simulated. Negatively charged bovine serum albumin is considered as the model protein analyte. The analyte transport in aqueous solution is controlled by an externally applied electrical field. The finite element method is employed for solving the equations of the charged spe...

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...

Ion abundances in the MALDI TOF mass spectra of the model peptides (bradykinin, alpha-melanocyte stimulating hormone, and melittin) change significantly as water is added to the solution used for dried droplet sample preparation. Changes in the surface tension of the solution can be invoked to explain some of the observed effects on the mass spectra. For example, at low surface tensions, the so...

Patterning substrates with biological reagents is a critical component of biosensor development. Many applications require multi-analyte patterning capabilities, with a need to deposit several species reproducibly with a high degree of precision. We demonstrate a piezoelectric inkjet printing system that is capable of creating sub-millimeter (down to 150microm) patterns of aqueous and nonaqueou...

in this study, the trace amounts of erythrosine, as a food dye is determined by cloud point extraction-scanometry (cpe-scanometry) as a new, facile, available, fast, sensitive, and low cost method. the method is based on the cpe of analyte from aqueous solution, diluting the extracted surfactant-rich phase with ethanol, transfer to plexiglas®cell and scanning the cells containing the analyte so...

In the immuno-oncology field, surrogate mouse monoclonal antibodies are often preferred in establishing proper PK/PD/efficacy correlations as well supporting anticipated to human translation. Thus, a highly sensitive and specific bioanalytical method is needed quantifying those after dosing mice. Unfortunately, when reagents, such recombinant target antigen anti-idiotypic antibody, not availabl...

Efficient mass transport through porous networks is essential for achieving rapid response times in sensing applications utilizing porous materials. In this work, we show that open-ended porous membranes can overcome diffusion challenges experienced by closed-ended porous materials in a microfluidic environment. A theoretical model including both transport and reaction kinetics is employed to s...

Ekins' ambient analyte theory predicts, counterintuitively, that an immunoassay's limit of detection can be improved by reducing the amount of capture antibody. In addition, it also anticipates that results should be insensitive to the volume of sample as well as the amount of capture antibody added. The objective of this study was to empirically validate all of the performance characteristics ...