biostudies-literatureLan HFundamental Research Funds for the Central UniversitiesNatural Science Foundation of Anhui ProvinceAnhui Science and Technology Major ProjectNational Natural Science Foundation of China837https://www.ebi.ac.uk/biostudies/studies/S-EPMC10144459biostudies-literatureUnknown14(4)Sessile droplets play a crucial role in the microreactors of biochemical samples. Acoustofluidics provide a non-contact and label-free method for manipulating particles, cells, and chemical analytes in droplets. In the present study, we propose a micro-stirring application based on acoustic swirls in sessile droplets. The acoustic swirls are formed inside the droplets by asymmetric coupling of surface acoustic waves (SAWs). With the merits of the slanted design of the interdigital electrode, the excitation position of SAWs is selective by sweeping in wide frequency ranges, allowing for the droplet position to be customized within the aperture region. We verify the reasonable existence of acoustic swirls in sessile droplets by a combination of simulations and experiments. The different periMicromachinesSwirl-like Acoustofluidic Stirring Facilitates Microscale Reactions in Sessile Droplets.PMC10144459202203a0702001382061138004JZ2022HGTA0328202103a070200145210557252105572; 82061138004; 321500172108085QF27932150017202103a07020014; 202203a07020013Zhang WLiu YQian JHu XLu SHuang LLan HZhang BfalseSwirl-like Acoustofluidic Stirring Facilitates Microscale Reactions in Sessile Droplets.Sessile droplets play a crucial role in the microreactors of biochemical samples. Acoustofluidics provide a non-contact and label-free method for manipulating particles, cells, and chemical analytes in droplets. In the present study, we propose a micro-stirring application based on acoustic swirls in sessile droplets. The acoustic swirls are formed inside the droplets by asymmetric coupling of surface acoustic waves (SAWs). With the merits of the slanted design of the interdigital electrode, the excitation position of SAWs is selective by sweeping in wide frequency ranges, allowing for the droplet position to be customized within the aperture region. We verify the reasonable existence of acoustic swirls in sessile droplets by a combination of simulations and experiments. The different peri2023-01-01T00:00:00Z2023 Apr2025-06-25T03:04:21.017Z2025-04-07T03:51:38.939ZS-EPMC101444593742107010.3390/mi14040837