Enhancing microcantilever capability with integrated AC electroosmotic trapping

Abstract

Microcantilevers are finding wide applications in detecting biochemical agents. However, their usage has been limited to highly concentrated samples to ensure sufficient deposition of agents onto cantilevers. A pre-concentration or enrichment step will expand their application range to more dilute, practical samples and real-time detection. This paper reports the integration of in-situ particle concentrators on microcantilevers. Only a thin metal layer on microcantilevers is required to generate microfluidic convection of particles from solution bulk onto microcantilever surfaces, greatly enriching local particle counts and enhancing sensitivity of the system. A working prototype is presented in the paper. Preliminary experiments concentrating latex particles were conducted and the particle concentration effect has been experimentally verified using AFM probes as microcantilevers. As ACEO concentrator has no dependence on particle properties, the method is expected to be applicable to bio-particles collection.

Enhancing the Performance of Surface-based Biosensors by AC Electrokinetic Effects - a Review

“…In order to maximize the sensitivity of a cantilever beam, the most desirable location for collection is at the cantilever tip, furthest away from the anchor. However, Islam et al (2007) successfully applied AC electroosmotic flow to drive polystyrene particles to a point near the anchor and detected a mass change after drying. (Park et al, 2008).…”

Design and characterization of a passive, disposable wireless AC-electroosmotic lab-on-a-film for particle and fluid manipulation

“…Of the various LOC devices which have followed many are based on electrical methods, including electrophoresis (EP) [3,4] electrowetting on dielectric (EWOD) [5,6] and electrokinetics effects (including dielectrophoresis (DEP) [7][8][9][10] AC electroosmosis (ACEO) [11][12][13][14] and the electrothermal effect [15,16]). These electrical LOCs have found numerous applications in processes such as drug delivery [17][18][19][20][21], cell analysis [22,23], analytical assay [24], and clinical diagnostics [25,26].…”

Three-dimensional non-linear AC electro-osmotic flow induced by a face-to-face, asymmetric pair of planar electrodes

“…Islam et al (2007) adopted a pair of parallel electrodes arranged in a face-to-face configuration to trap particles on the surface of a microcantilever for the enhancement of detection capability. Chiou et al (2008) presented a light-actuated AC electro-osmosis mechanism realized by sandwiching a liquid between a light-actuated virtual electrode and a transparent indium tin oxide (ITO) electrode.…”