Silicon nanowire field effect transistors (FETs) have emerged as ultrasensitive, label-free biodetectors that operate by sensing bound surface charge. However, the ionic strength of the environment (i.e., the Debye length of the solution) dictates the effective magnitude of the surface charge. Here, we show that control of the Debye length determines the spatial extent of sensed bound surface charge on the sensor. We apply this technique to different methods of antibody immobilization, demonstrating different effective distances of induced charge from the sensor surface.
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http://dx.doi.org/10.1021/ja205684a | DOI Listing |
Langmuir
January 2025
Faculty of Pharmaceutical Sciences, Tokyo University of Sciences, 2461 Yamazaki Noda, Chiba 278-8510, Japan.
The current study deals with a theoretical analysis of diffusiophoresis of a soft particle, consisting of a hydrophobic charged rigid core coated with an ion- and fluid-penetrable charged polymer layer suspending in an electrolyte medium in reaction to an applied concentration gradient. The inner core's hydrophobicity is assumed to be characterized by a surface-charge-dependent slip length parameter. Based on a weak particle charge consideration, the governing equations describing the flow phenomena are solved theoretically to deduce a semianalytic general diffusiophoretic mobility expression applied to an arbitrary Debye layer thickness.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
We study the effects of patch potentials in the electrostatic double-layer force. In the limit of small potentials, we derive an analytic expression where the force is additive in terms of the Fourier components of the potential. Moreover, each term has a contribution of the same form as the standard double-layer force with an effective Debye length.
View Article and Find Full Text PDFLangmuir
December 2024
School of Chemical and Process Engineering, University of Leeds, Leeds, LS2 9JT, United Kingdom.
To form nonspherical emulsion droplets, the interfacial tension driving droplet sphericity must be overcome. This can be achieved through interfacial particle jamming; however, careful control of particle coverage is required. In this work, we present a scalable novel batch process to form nonspherical particle-stabilized emulsions.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
December 2024
Department of Chemical Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Hybrid nanoplasmonic structures composed of subwavelength apertures in metallic films and nanoparticles have recently been demonstrated as ultrasensitive plasmonic sensors. This work investigates the electrokinetically driven propagation of the assembly mechanism of the metallic nanoparticles through nanoapertures. The Debye-Hückel approximation for a symmetric electrolyte solution with overlapping electrical double layers (EDLs) is used to obtain an analytical solution to the problem.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
The phenomenon of underscreening in concentrated electrolyte solutions leads to a larger decay length of the charge-charge correlation than the prediction of Debye-Hückel (DH) theory and has found a resurgence of both theoretical and experimental interest in the chemical physics community. To systematically understand and investigate this phenomenon in electrolytes requires a theory of concentrated electrolytes to describe charge-charge correlations beyond the DH theory. We review the theories of electrolytes that can transition from the DH limit to concentrations where charge correlations dominate, giving rise to underscreening and the associated Kirkwood Transitions (KTs).
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