Efficient Hydrophilic Array Deposition Using Ultrasonic Atomization and Off-the-Shelf Perforated Masks

This paper presents a novel method for fabricating hydrophilic arrays on hydrophobic substrates via a masked ultrasonic atomization process combined with off-the-shelf perforated masks. By generating a fine mist of hydrophilic reagent solution and directing it through readily available perforated masks, our technique affords precise spatial and temporal control over droplet formation. This capability enables accurate patterning and sequential multi-material deposition, which is essential for diverse applications including biological analysis, chemical reactions, materials synthesis, and high-throughput drug screening. The method has been validated through experiments on various substrates, such as polypropylene sheets and polystyrene petri dishes, and demonstrated via bacterial culture assays where controlled reagent gradients modulated bacterial growth. In addition to its cost-effectiveness and simplicity, our approach offers scalability and adaptability for advanced microfluidic devices. The results indicate improvements over traditional droplet manipulation techniques, positioning this method as a promising platform for novel microfluidic applications.