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A new normally open valve is presented. A polydimethylsiloxane (PDMS) cavity with two microchannels were fabricated using soft lithography technology. The one end of the cavity is arc-shaped at the joint with the microchannel. A steel ball is placed into the PDMS cavity mounted on a piezoelectric substrate with an interdigital transducer (IDT). Surface acoustic wave excited by the IDT is used for driving the steel ball to the arc area, leading to blocking the inlet of the microchannel. The microvalve was then closed. The switching characteristics were experimentally demonstrated using red ink solution. [ABSTRACT FROM AUTHOR]

A new method for dispatching microfluid is presented. A steel ball of 2mm diameter is placed on a 128 degrees YX LiNbO3 substrate. A PDMS frame is mounted on the piezoelectric substrate for defining the movement trajectory of the steel ball. Paper testing zone is fixed on a PDMS block for the target of the microfluidic dispatch. The steel ball is driven by surface acoustic wave, and carried microfluid at the outlet of the PDMS microchannel to the paper testing zone. Red ink solution is used to demonstrate the fluid dispatch. [ABSTRACT FROM AUTHOR]

A new paper-based microfluidic device is fabricated on a piezoelectric substrate. A polydimethylsiloxane channel filled with cotton threads is mounted on the piezoelectric substrate with an interdigital transducer. A testing filter paper with dried reaction solution is coated on the end of the cotton thread. Sample solution is driven to the cotton thread channel and transported to testing area for microfluidic analysis. Red ink solution and color development reaction of starch are demonstrated for microfluidic operation and analysis. Results show that the linear velocity of microfluidic transportation in the cotton thread channel is 4.558 mm/s, and color development reaction of starch is successfully implemented. [ABSTRACT FROM AUTHOR]

A new method for heating microfluid in a polydimethylsiloxane (PDMS) array chip is presented. Interdigital transducers are fabricated on a 128° YX-LiNbO3substrate. A 4 × 4 polydimethylsiloxane array chip is placed on the piezoelectric substrate, where a heat transfer pillar with a heat transfer sheet is connected with every reaction zone in the PDMS array chip. An oil droplet is driven for selecting special heat transfer pillar to heat the microfluid in the special reaction zone. Theoretical calculation of heat transfer is finished. At equilibrium state, the emitted energy per second during heat transfer is 7.436 mJ at 30.0 dBm electric signal power. [ABSTRACT FROM AUTHOR]