This paper reports on the fabrication and experimental characterisation of improved design AC eletroosmotic micropumps. Since the first study and analysis of AC electroosmosis by Ramos et al. [1], many devices have been fabricated and tested [2]. The basic planar electrode design was improved and increased pumping velocities were measured. Among the proposed improvements, 3D electrode design se...

Previous publications 1, ~ in this series have dealt with the preparation and electrochemical properties of the activated (electronegative) collodion membrane. The activation consisted of an oxidation of the nitrocellulose, a process which caused an increase in the number of dissociable groups in the pores of the membrane. Such membranes show more pronounced effects than similar untreated membr...

Under the influence of an ac electric field, electrolytes on planar microelectrodes exhibit fluid flow. The nonuniform electric field generated by the electrodes interacts with the suspending fluid through a number of mechanisms, giving rise to body forces and fluid flow. This paper presents the detailed experimental measurements of the velocity of fluid flow on microelectrodes at frequencies b...

Patch clamping depends on a tight seal between the cell membrane and the glass of the pipet. Why does the seal have such high electric resistance? Why does the patch adhere so strongly to the glass? Even under the action of strong hydrostatic, adhesion, and electrical forces, it creeps at a very low velocity. To explore possible explanations, we examined two physical models for the structure of...

This paper reports the application of ampholyte-based isoelectric focusing in poly(dimethylsiloxane) (PDMS) using methylcellulose (MC) to reduce electroosmosis and peak drift. Although the characteristics of PDMS make it possible to fabricate microfluidic chips using soft lithography, unstable electroosmotic flow (EOF) and cathodic drift are significant problems when this medium is used. This p...

Real-time detection of low-concentration pathogenic/ toxic bioparticles is important for deterring infectious diseases and bioterrorism, which is difficult to achieve for lab-on-a-chip. Currently, sensitivity is achieved through time-consuming culturing or sophisticated processing, often unfeasible under field conditions. Real-time particle enrichment will improve sensor capability. This paper ...

Effective and versatile microfluidic pumps can be produced by utilizing various electrokinetic effects, such as electrohydrodynamics (EHD), induced-charge electroosmosis (ICEO) and dielectrophoresis (DEP). Among these, traveling-wave EHD (twEHD) has emerged as a powerful pumping mechanism due to its potential for miniaturization and the ability to pump a variety of liquids. However, when twEHD ...

An instrument simulator was developed for high-performance capillary electrophoresis which allows for fast graphic illustration of the effect of a large number of variables on the shape of the electropherogram. The input data of the separands are values of pK and mobilities at 25°C and infinite dilution. The instrument parameters that can be varied include capillary material, lengths, inside di...