Paper Based Microfluidic Device Using Surface Acoustic Wave as Driving Source

It is necessary to implement pretreatment operations for a paper based microfluidic device. A paper based microfluidic device with SAW driving microfluid has been implemented. Trance analyte to be detected was absorbed into a filter paper at first, and mounted on PDMS blocks on a piezoelectric substrate to ensure that the indicting filter paper has a little gap with the piezoelectric substrate. Reagents were then pipetted on the piezoelectric substrate and transported by surface acoustic wave excited by an interdigital transducer, which was fabricated on a 1280-yx LiNbO3 using micro-electrical technology. A color was developed due to chemical reaction, and the analyte concentration was evaluated by its grey value. Nitrate ion was detected using the microfluidic system.

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Droplets Transportation on a Piezoelectric Substrate with an Obstacle

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.339.104 ◽

2013 ◽

Vol 339 ◽

pp. 104-108

Author(s):

Xiang Ting Fu ◽

Yan Zha ◽

An Liang Zhang

Keyword(s):

Acoustic Wave ◽

Radio Frequency ◽

Surface Acoustic Wave ◽

Acoustic Streaming ◽

Microfluidic System ◽

Frequency Signal ◽

Radio Frequency Signal ◽

Generate Surface ◽

Interdigital Transducer ◽

Piezoelectric Substrate

A method for a droplet transportation by jumping a obstacle on piezoelectric substrate is presented, and a device for the droplet transportation is implemented on a 128° yx-LiNbO3 piezoelectric substrate. An interdigital transducer and a reflector are fabricated on the piezoelectric substrate using microelectric technology. Hydrophobic film is coated on the area free of electrodes and a polydimethylsilicone obstacle is mounted on it. A radio frequency signal amplified by a power amplifier is applied to the interdigital transducer to generate surface acoustic wave. When the surface acoustic wave meets with the droplet on the piezoelectric substrate during transportation, part of acoustic wave enegy is radiated into the droplet, leading to internal acoustic streaming. Once the radio frequency signal with appropriate amplitude is suddenly decreased, part of the droplet will jump the obstacle due to interial force. Red dye solution drops are demonstrated for transportation experiments. Results show that a droplet can be transported from one side to another of the obstacle on piezoelectric substrate by help of surface acoustic wave. The presented method is helpful for microfluidic system on a piezoelectric substrate.

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Splitting Drops on a Piezoelectric Substrate by Help of Surface Acoustic Wave

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.336-338.80 ◽

2013 ◽

Vol 336-338 ◽

pp. 80-83

Author(s):

Ai Liang Zhang ◽

Xiang Ting Fu ◽

Yan Zha

Keyword(s):

Acoustic Wave ◽

Surface Acoustic Wave ◽

Biochemical Analysis ◽

Acoustic Streaming ◽

Microfluidic System ◽

Preparation Technique ◽

Sample Preparation Technique ◽

Interdigital Transducer ◽

Red Dye ◽

Piezoelectric Substrate

A new method for splitting drops on a piezoelectric substrate is presented. An interdigital transducer with the period of 144μm is fabricated on a 128° yx-LiNbO3piezoelectric substrate using microelectric technology. Intermittent surface acoustic wave is generated by an on-to-off radio frequency signal, which is applied to the interdigital transducer, and then radiates into a drop on the acoustic path of the piezoelectric substrate, leading to discontinuous acoustic streaming. A part of the drop is split due to inertia when the surface acoustic wave is suddenly disappeared. Red dye solution drops are demonstrated for fission experiments, and mixture operation of two drops is also implemented using the fission method. Results show that a drop can be split by help of surface acoustic wave, and the distance of two daughters is determined on the volume of the drop. The presented drop fission method provides a new sample preparation technique, which is helpful for microfluidic biochemical analysis in a microfluidic system.

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Thread-Piezoelectric-Substrate Based Low-Cost Microfluidic Device

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.130-134.3329 ◽

2011 ◽

Vol 130-134 ◽

pp. 3329-3333

Author(s):

An Liang Zhang ◽

Qin Jiang Han

Keyword(s):

Chemical Analysis ◽

Acoustic Wave ◽

Microfluidic Device ◽

Low Cost ◽

Nitrite Ion ◽

Pdms Film ◽

Interdigital Transducer ◽

Filter Papers ◽

Rf Signal ◽

Piezoelectric Substrate

A new low cost microfluidic device has been designed and fabricated. Three thread microchannels were fabricated using tape and three indicting filter papers were also made by dipping three filter papers into sodium nitrite with different concentration. The side of the thread microchannels was connected to the indicting filter papers and then mounted on a 1280yx-LiNbO3piezoelectric substrate, on which an interdigital transducer and reflector were fabricated using microeletric technology. PDMS film was coated to avoid the evaporation of microfluid transporting in the thread based microchannels. When a 25.5MHz RF signal with 25.4dBm power was applied on the IDT, the microfluid on the piezoelectric substrate was actuated by surface acoustic wave and transported along the thread microchannels, and reacted with nitrite ion in the indicting filter paper. Experimental results show that the thread-piezoelectric substrate microfluidic device can be used for biological or chemical analysis.

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Surface Acoustic Wave Gyroscopic Effect in an Interdigital Transducer

Sensors ◽

10.3390/s19010106 ◽

2018 ◽

Vol 19 (1) ◽

pp. 106

Author(s):

Xueping Sun ◽

Weiguo Liu ◽

Xiuting Shao ◽

Shun Zhou ◽

Wen Wang ◽

...

Keyword(s):

Acoustic Wave ◽

Surface Acoustic Wave ◽

Stop Band ◽

Fem Analysis ◽

Band Edge ◽

Dispersion Characteristics ◽

The Finite Element Method ◽

Gyroscopic Effect ◽

Interdigital Transducer ◽

Piezoelectric Substrate

The surface acoustic wave (SAW) gyroscopic effect in an interdigital transducer (IDT) deposited on a piezoelectric substrate is different from that in the piezoelectric substrate due to a reflection induced by IDT. In this work, an extended coupling-of-mode (COM) model including the gyroscopic effect and the reflection was developed to analyze the SAW gyroscopic effect. First, dispersion characteristics parameters of SAW were fitted according to the data derived using the finite element method (FEM). Then, variations of stop band edge frequency were calculated using the extended COM theory by integrating dispersion characteristics parameters into the COM model. We compared its results with those obtained via FEM analysis to confirm the proposed model’s validity. We found that the variation in stop band edge frequency related to gyroscope effect reached the maximum value with a zero reflectivity value. For split IDT, the sensitivity of gyroscope effect is 0.036 Hz/rad/s with a lower than 1% normalized thickness. Conversely, the value of sensitivity was almost zero for bidirectional IDT and electrode width controlled single-phase unidirectional transducer (EWC/SPUDT).

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