Acoustic-Actuated Robotic End-Effector for Open-Environment Microfluidics Manipulation

Efficient manipulation of microscale fluids in open environments remains a significant challenge due to dominant viscous forces, risks of evaporation, and limited integration with robotic systems, all of which impede rapid mass transfer critical for applications such as diagnostics, drug discovery, and nanomaterial synthesis. Conventional approaches, including enclosed microfluidic channels or macroscopic robotic handling, often restrict sample accessibility and lack the precision required for sophisticated fluid control at the microscale. This study introduces a novel acoustic-actuated robotic end-effector designed for versatile open-environment microfluidics manipulation. By employing acoustically driven microbubble oscillations within a micropipette tip, the system generates intense, localized micro-vortices streaming that overcome the constraints of low Reynolds number flows. Through detailed flow analysis and experimental validation with high-viscosity liquids and nanoparticle dispersions, we have confirmed a significant enhancement in mass transfer efficiency. The system provides precise control over fluid dynamics, governed directly by the input voltage. Its open environment ensures easy access for sampling, broad compatibility with standard optical microscopy, and a low risk of contamination. These characteristics establish it as an accurate, cost-effective, and adaptable platform for applications like droplet assays, nanomaterial preparation, and the regulation of cellular environments.