Enhancement of biosensing performance in a droplet-based bioreactor by in situ microstreaming

Abstract

A droplet-based micro-total-analysis system involving biosensor performance enhancement by integrated surface-acoustic-wave ͑SAW͒ microstreaming is shown. The bioreactor consists of an encapsulated droplet with a biosensor on its periphery, with in situ streaming induced by SAW. This paper highlights the characterization by particle image tracking of the speed distribution inside the droplet. The analytebiosensor interaction is then evaluated by finite element simulation with different streaming conditions. Calculation of the biosensing enhancement shows an optimum in the biosensor response. These results confirm that the evaluation of the Damköhler and Peclet numbers is of primary importance when designing biosensors enhanced by streaming.

Kinetic studies of attachment and re-orientation of octyltriethoxysilane for formation of self-assembled monolayer on a silica substrate

“…Octadecyltrichlorosilane (OTS) and octadecyltrimethoxysilane (OTMS) are widely used alkylsilane for synthesising hydrophobic surfaces with 18 carbon atom hydrocarbon chain present between terminal and head group [15][16][17]. Among other amphiphillic molecules, fluoro-alkyl-substituted silanes also favour this property of hydrophobicity.…”

Acoustic micromixing increases antibody-antigen binding in immunoassays

“…Acoustic microstreaming, here referred to as acoustic micromixing, uses audible sound waves to rapidly and efficiently mix solutions in small volumes (e.g., 10-100 μL range) (Petkovic-Duran et al 2009). Such mixing can be performed in closed microfluidic channels (Ahmed et al 2009), open or encapsulated droplets (Ducloux et al 2010;Galopin et al 2007) and open microtitre wells (Liu et al 2003b;Petkovic-Duran et al 2009). In many situations, the micromixing result in the total mixing of a small volume within sub-second to a few minutes compared to several hours required for pure diffusion-based mixing (Liu et al 2003a, b;Petkovic-Duran et al 2009).…”

Mass transfer enhancement and surface functionalization in digital microfluidics using AC electrowetting: the smaller, the better

“…In microfluidics applications, steady microstreaming is one of the rare phenomena based on inertial effects, which does not require a high value of the Reynolds number. When it is generated by means of acoustic waves (Sadhal 2012) or surface acoustic waves (Li et al 2009), it can be used to pump a liquid, to trap biochemical reagents within vortices, enhancing thus chemical reactions (Lutz and Chen 2003), to favour stirring or mixing in microchambers (Liu and Yang 2002;Wiklund et al 2012) with sometimes the objective to enhance biosensing performance (Ducloux et al 2010).…”