The Fusion Of Digital Microfluidics In A Micro-channel Based On SAW

The fusion is an important operation for microfluidic chip in micofluidic analysis,and has been paid attention by researchers of microfluids.Surface Acoustic Wave (SAW) devices have been widely applied in many areas dueto small size, reliability and simple process. In this paper, a new surface acoustic wave(SAW)-based method for microfludic fusion in a micro-channel is proposed. Aninterdigital transducer and a reflector were fabricated on a1280YX-LiNbO3substrateusing microelectric technology. A PDMS microchannel, which was fabricated usingmethod of molding, was mounted onto the piezoelectric substrate. Paraffin oil and microfluids to be fused were then injected into the microchannel by a microsyringe. After anamplified RF signal is applied to the interdigital transducer, surface acoustic wave wasexcided and the microfluids to be fused in the micro-channel was actuated. At the sametime, the propagation characteristics of SAW along the piezoelectric substrate wereanalyzed,and its unit volume force acted on the microfluid was also simulated..The experiments for fusing microfluids in the microchannel filled with paraffin oilwere done using red dye solution and blue dye solution microfluid. The results show thatthe microfluids in the micro-channel can be fast fused by the help of SAW, during whichit was depended on the RF signal power applied to the interdigital transducer, diameterand space of microfluids to be fused. In addition, the experimental results were evaluatedwith mixing index, which was calculated by gray value of images. Compared to reportedfusion techniques, the presented fusion method has the advantages such as high fusingefficiency, low cost and easy to operation. The work provides an inexpensive andintegratable fusion cell for a microfluidic chip, which was valuable for microfluidicanalysis.