The realm of microfluidics, a field at the intersection of nanotechnology, biochemistry, engineering, and physics, has already revolutionized how scientists manipulate liquids on a minuscule scale. These “lab-on-a-chip” systems have transformed tasks once confined to painstaking test-tube work, offering benefits like real-time, high-throughput testing with minimal sample volumes, crucial for applications ranging from point-of-care diagnostics to rapid viral testing. However, a persistent challenge in these systems is the precise and contactless manipulation of fluid droplets without contamination or damage to sensitive biological and chemical samples. While light, heat, and magnetic or electric fields have been explored, they often require strong fields or high temperatures that can compromise delicate materials. A new breakthrough introduces an innovative solution: a sound-based control system that allows a microfluidic processor to precisely manipulate droplets across an exceptionally broad range of volumes.
The minimalist device, compatible with various substrates including metals, polymers, and glass, is also biocompatible, positioning it as a potentially transformative tool for applications in biology, chemistry, and integrated lab-on-a-chip systems.
Previous attempts to use acoustic fields for droplet manipulation were limited by the types of fluids they could handle and a narrow volume range, typically from hundreds of nanoliters to tens of microliters. The newly developed microfluidic processor, or sound-controlled fluidic processor (SFP), however, shatters these limitations. Thanks to an integrated ultrasonic transducer and a specially designed liquid-infused slippery surface that minimizes sample adhesion, the SFP can precisely manipulate droplets ranging from a tiny 1 nanoliter (nL) up to a massive 3000 microliters (μL). This represents an unprecedented range of control.
The microfluidic processor system’s versatility stems from its ability to sculpt acoustic pressure fields simply by adjusting the position of the sound source. This allows researchers to precisely push, pull, mix, or even split droplets on demand, all without physical contact. The non-invasive nature and high precision of this acoustic manipulation make the SFP an ideal candidate for highly sensitive applications such as point-of-care diagnostics, high-throughput drug screening, and automated biochemical assays. It also holds promise for streamlining reagent delivery in complex high-throughput systems, reducing potential contamination and increasing efficiency.
Beyond these immediate applications, the microfluidic processor offers significant potential for fundamental biological research, particularly in the growing field of organoid research. The researchers successfully demonstrated this by culturing mouse primary liver organoids and using the SFP to screen for molecules like verapamil, a drug known for its liver-protective properties. This showcases the system’s capacity to facilitate precise and controlled experimentation on complex biological models.
Looking ahead, the developers plan to integrate their sound-controlled microfluidic processor into fully automated, programmable lab-on-a-chip systems. Future enhancements include further miniaturization and the incorporation of multiple acoustic sources. This will enable parallel operations, significantly increasing throughput and paving the way for next-generation diagnostics and sophisticated chemical processing technologies that leverage the power of sound for unparalleled fluid control.
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