Microfluidic grid creates concentration gradient to test cancer drugs

Part of testing and screening drugs involves evaluating the necessary concentration of their chemical components. Concentration gradients, or gradual changes in the concentration of molecules, are often created manually or robotically, using methods that are error prone, labor intensive, or prohibitively costly.

As an alternative, microfluidic designs can provide precise control over solute concentrations in space and time, reduce errors, and save potentially precious reagents. Yadav et al. designed and manufactured a microfluidic concentration gradient generator and applied it to test the chemotherapeutic molecule curcumin.

The device is made of 9 by 9 interwoven microfluidic channels. Two inlets allow liquid in – one with no solute and another with a high concentration. The streams mix in the mesh to make varying concentrations, ranging from zero to the maximum concentration, in ten outlets.

To manufacture the mesh, the team created a template by squeezing ceramic fluid between two parallel plates with pre-designed holes. When the plates separate, air enters the holes and displaces the fluid to produce the mesh shape. After solidifying, the template was transferred onto a polymer and bonded with a glass plate.

“Our fabrication method is unconventional, scalable, and customizable,” said author Abhijit Majumder. “Starting from the same simple layout of shaped ceramic fluid, users can achieve an infinite number of designs. Such options are not available in current microfabrication methods.”

After testing the device with fluorescent microscopy and computational techniques, the researchers used it to generate a gradient of curcumin and evaluate its effect on cervical cancer cells. The results matched conventional, gold standard drug testing techniques.

Source: “Scalable large-area mesh-structured microfluidic gradient generator for drug testing applications,” by Shital Yadav, Pratik Tawade, Ketaki Bachal, Makrand A. Rakshe, Yash Pundlik, Prasanna S. Gandhi, and Abhijit Majumder, Biomicrofluidics (2022). The article can be accessed at https://doi.org/10.1063/5.0126616 .