title: Hybridization enhancement using cavitation microstreaming.
abstract: Conventional DNA microarray hybridization relies on diffusion of target to surface-bound probes, and thus is a rate-limited process. In this paper, a micromixing technique based on cavitation microstreaming principle that was developed to accelerate hybridization process is explained. Fluidic experiments showed that air bubbles resting on a solid surface and set into vibration by a sound field generated steady circulatory flows, resulting in global convection flows and, thus, rapid mixing. The time to fully mix dyed solutions in a 50-microL chamber using cavitation microstreaming was significantly reduced from hours (a pure diffusion-based mixing) to 6 s. Cavitation microstreaming was implemented to enhance DNA hybridization in both fluorescence-detection-based and electrochemical-detection-based DNA microarray chips. The former showed that cavitation microstreaming results in up to 5-fold hybridization signal enhancement with significantly improved signal uniformity, as compared to the results obtained in conventional diffusion-based biochips for a given time (2 h). Hybridization kinetics study in the electrochemical detection-based chips showed that acoustic microstreaming results in up to 5-fold kinetics acceleration. Acoustic microstreaming has many advantages over most existing techniques used for hybridization enhancement, including a simple apparatus, ease of implementation, low power consumption (approximately 2 mW), and low cost.
authors.affiliation: Microfluidics Laboratory, Motorola Labs, Tempe, Arizona 85284, USA. hliu24@mainex1.asu.edu
authors.forename: Robin Hui
authors.initials: RH
authors.lastname: Liu
authors.forename: Ralf
authors.initials: R
authors.lastname: Lenigk
authors.forename: Roberta L
authors.initials: RL
authors.lastname: Druyor-Sanchez
authors.forename: Jianing
authors.initials: J
authors.lastname: Yang
authors.forename: Piotr
authors.initials: P
authors.lastname: Grodzinski
mesh_terms: D000162:Acoustics; D007700:Kinetics; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation*; D020641:Polymorphism, Single Nucleotide; D012212:Rheology