Hexagonal Microfluidic Mixing Probe for Flow Concentration Gradients on Suspended Cells*

In this study, we introduce a novel hexagonal microfluidic mixing probe (MMP) that combines the concepts of microfluidic probe (MFP) and Christmas-tree concentration gradient generators. The advanced MMP generates six concentric hydrodynamic flow confinements (HFC) with five distinct reagent concentrations. The system integrates an Open micro-electro-fluidic (OMEF) biochip of interdigitated electrodes (IDE) positioned below the HFC footprint. Additionally, the electrically activated bottom substrate employs dielectrophoretic (DEP) force for frequency-based selective capturing of suspended cells. The MMP-generated HFCs are positioned atop the DEP-captured suspended cells, exposing them simultaneously to six distinct reagent concentrations. This system enables the execution of multiplex spatiotemporally controlled experiments to assess the effects of various reagent concentrations and their combinations. This versatile tool promises to revolutionize drug dosage precision, potentially leading to a more efficient and cost-effective preclinical testing protocol.