• The present patent disclosure relates to Fabricating Microfluidic Devices (flow control devices) on porous, hydrophilic substrates, especially for lab-on-a-chip and lateral flow devices.
• To see the device’s operation, light-colored toner encloses hydrophilic areas. This process do not affect fluid flow within microfluidic network.
• The method involves manual or automatic application of hydrophobic toner using laser printing. Multiple microfluidic devices can be stacked to make a 3D structure.

The Method for Fabricating Microfluidic Devices on Porous Substrates comprises following steps:

• Applying hydrophobic toner material to a porous substrate in a specific pattern on one surface. The porous substrate is suitable for creating microfluidic devices.
• Subjecting the substrate with the hydrophobic toner to a thermal treatment process, ensuring the complete penetration of at least one hydrophobic polymer from the toner material throughout the thickness of the porous substrate. This forms a fluid-resistant barrier on the substrate.
• Adding an additional toner layer selectively to the top, bottom, or both surfaces of the patterned substrate, effectively sealing it with hydrophobic toner material to create a leak-proof microfluidic device.
• Subjecting the substrate with the additional toner layer to a gentle thermal treatment process to ensure the device is leak-proof by allowing lateral permeation of the hydrophobic polymers.
• This method also defines at least one hydrophilic region connected to a fluid impervious hydrophobic barrier on the porous substrate.