title: Microfabricated valveless devices for thermal bioreactions based on diffusion-limited evaporation.
abstract: Microfluidic devices that reduce evaporative loss during thermal bioreactions such as PCR without microvalves have been developed by relying on the principle of diffusion-limited evaporation. Both theoretical and experimental results demonstrate that the sample evaporative loss can be reduced by more than 20 times using long narrow diffusion channels on both sides of the reaction region. In order to further suppress the evaporation, the driving force for liquid evaporation is reduced by two additional techniques: decreasing the interfacial temperature using thermal isolation and reducing the vapor concentration gradient by replenishing water vapor in the diffusion channels. Both thermal isolation and vapor replenishment techniques can limit the sample evaporative loss to approximately 1% of the reaction content.
authors: Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
authors: Fang
authors: F
authors: Wang
authors: Ming
authors: M
authors: Yang
authors: Mark A
authors: MA
authors: Burns
mesh_terms: D004058:Diffusion; D044085:Microfluidics / Q000295:instrumentation*; D008956:Models, Chemical; D016133:Polymerase Chain Reaction; D011312:Pressure; D013696:Temperature; D013816:Thermodynamics; D014835:Volatilization; D014867:Water
chemical_list: D014867:Water