Force spectroscopy on single molecules is a technique that is used to study the mechanical and structural properties of biomolecules. A relatively new force spectroscopy technique is acoustic force...Show moreForce spectroscopy on single molecules is a technique that is used to study the mechanical and structural properties of biomolecules. A relatively new force spectroscopy technique is acoustic force spectroscopy (AFS), which exploits acoustic waves to generate a wide range of forces with high pulling rates. A piezoelectric transducer is used to generate acoustic waves at specific resonance frequencies. Acoustic standing waves exert forces on micro-particles and pull them to acoustic pressure nodes. However, commercially available AFS flow cells are expensive and users find them nontrivial to operate. Here we present a new AFS flow cell design where we placed the piezoelectric transducer directly on top of the fluid channel of the flow cell to reduce the loss of acoustic pressure between the transducer and fluid. We used 3D finite element method simulations and found that the acoustic pressure profile is more complex than expected due to acoustic variations in the xy-plane. However, we found that the dimensions of the flow cell can be optimised to minimise acoustic variations in the xy-plane, demonstrating that more homogeneous pulling forces can be achieved. We performed AFS measurements on the new flow cell design, but we were not able to demonstrate an acoustic force. We anticipate this study helps to further optimise the AFS flow cell design, resulting in maximised pulling forces with minimal variations in the xy-plane.Show less
