A microfluidic concentration gradient generator for simultaneous delivery of two reagents on a millimeter-sized sample


Microfluidic concentration gradient generators (μCGGs) are indispensable parts of many emerging lab-on-a-chip platforms for biological studies and drug delivery applications. Most of the μCGGs reported in the literature can only generate the desired concentration gradients in a micron-sized sample (e.g., cells). As such, there is an unmet need to design a μCGG that can generate continuous concentration gradients of multi reagents (e.g., drugs) in a millimeter-sized sample (e.g., tissue). Herein, we report the proof-of-concept of this class of μCGG by combining a modified tree-like CGG with a micromixer. By conducting both experimental investigation and numerical analysis, we show that the proposed device can generate a continuous concentration gradient of two reagents and deliver all the possible combinations of their concentrations to a millimeter-sized sample. The proposed device can be used in a broad range of applications, especially ex-vivo drug chemosensitivity testing in personalized medicine.

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We would like to express our great appreciation to Dr. Javad Mirnajafizadeh, head of Cell-Electrophysiology Laboratory of Tarbiat-Modares University, for providing the neonatal mouse brain and the vibratome slicer.

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Correspondence to Mohammad Said Saidi.

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Article Highlights

• Development of a new type of microfluidic concentration gradient generators (μCGG).

• Millimeter-sized sample/Multi-reagents/ Continuous CGG.

• The proposed μCGG is highly suitable for drug delivery at a tissue level.

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Rismanian, M., Saidi, M.S. & Kashaninejad, N. A microfluidic concentration gradient generator for simultaneous delivery of two reagents on a millimeter-sized sample. J Flow Chem 10, 615–625 (2020). https://doi.org/10.1007/s41981-020-00104-7

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  • Micromixer
  • Concentration gradient generator
  • Microfluidics
  • Sensitivity analysis