As being one of the contactless and label free methods in microfluidics, acoustofluidics has provided great benefits to the researchers in terms of cell/particle analysis, separation, and screening. This recent technology uses the particle handling phenomenon of acoustics wave in microfluidic platforms and lets scientists benefit contact-free and effective particle and cell manipulation in the field of microfluidics. Throughout this study, four different acoustofluidic platforms have been designed, fabricated and tested to promote the abundant usage of acoustofluidics technology. The first and second chips were designed to enable cell/particle position change in an acoustic microfluidic chip since position of particles/cells inside the acoustofluidic chip is strictly dependent on the channel geometry and it is fixed once the microfluidic platform is fabricated. To solve this restriction, fluidic boundary needs to be separated from the acoustic boundary. In the first study, acoustofluidic platform with two adjacent microchannels were designed. One of the microchannels was used to flow particles/cells, and second microchannel with staircase structure was used to change the position of particles/cells inside the main microfluidic channel by changing the effective channel width. Using this chip we successfully demonstrated the particle position change inside the main microfluidic channel. The second acoustofluidic platform was designed and fabricated by filling the side of microfluidic channel with a transparent material, polydimethylsiloxane (PDMS) so that position of acoustic pressure nodes can be adjusted depending on the width of the PDMS slab. By the help of soft-lithography techniques PDMS wall could be successfully integrated into side of the microfluidic channel in a costeffective manner since previous studies required expensive equipment such as laser to integrate the PDMS slab. Fabrication of this acoustofluidic chip was implemented and yielded successful results of particle manipulation by the help of acoustophoresis when tried with different types of particles. In the third acoustofluidic chip flow control capability for on-chip laboratory studies was enabled since acoustofluidic platforms lack on-chip flow control attribute. For that reason, microvalves were designed and integrated into acoustofluidic platform so that scholars who study particle/cell manipulation requiring on-chip flow control can benefit and modify this method. This platform was also successfully fabricated and used for on-chip culture medium exchange to enable intradroplet cell culture. The last platform was to integrate acoustofluidic technology with droplet microfluidics so that acoustic platforms can take advantage of droplet microfluidics since they provide efficient cell screening, high throughput, and ability to run parallel experiments. Outcome of fabricating this chip was also rewarding and preliminary experiments to test this platform showed promising results for future works. To summarize, since acoustofluidics is an emerging and rapidly growing technology and science field in last two decades some of the limitations arose in this technology. Those restrictions are addressed in the following sections and alternative fabrication methods to solve those restrictions and the outcome of those methods are discussed.
