Laminar Flow Microfluidic Concentration Gradient for Lipophilic Drug Screening

The invention extracts and removes the oil phase from the microdroplet generation system, replacing it with an aqueous-based segmented flow system. This elimination of the oil phase removes the harmful diffusion effect that prevented use of lipophilic compounds, while still achieving discrete microdroplet formation through alternative hydrodynamic mechanisms at a T-junction or flow focusing geometry.

The invention changes the fundamental parameter of the continuous phase from oil-based to aqueous-based buffer liquid. This parameter change transforms the system from one that causes diffusion of lipophilic substances into one that is compatible with all types of compounds, including lipophilic ones, while maintaining the ability to generate discrete concentration profiles through controlled flow segmentation.

The invention replaces the mechanical segmentation approach (creating discrete microdroplets) with a continuous flow approach that generates a continuous concentration gradient. Instead of relying on the number of discrete droplets to achieve concentration resolution, the system uses controlled diffusion and flow dynamics to create a continuous spectrum of concentrations that can be scanned optically, thereby achieving high resolution without increasing device complexity.

The invention transitions from a discrete one-dimensional segmentation (individual microdroplets with discrete concentrations) to a continuous spatial gradient along the flow channel. By creating a continuous concentration profile that varies along the length of the channel, the system achieves high concentration resolution through spatial distribution rather than through increasing the number of discrete units.