Current Research: Hot embossing techniques for BioMEMS research & design

The current standard in microfluidic prototyping is polydimethylsiloxane (PDMS) devices molded from SU-8 structures produced by photolithography.  However, PDMS lacks the robust characteristics needed for many real-world applications, resulting in a necessary material change during the translational phase of research.  We are interested in utilizing practical materials at all stages of microfluidic device design by taking advantage of hot embossing of thermoplastic materials.

Dry resin on steel wafer prior to electrodeposition

Dry resin on steel wafer prior to electrodeposition

Nickel microfluidic channel molds after electrodeposition and resin removal

Nickel microfluidic channel molds after electrodeposition and resin removal

Electrode integration is a critical element in point-of-care diagnostic devices, but existing processes are complex, expensive, or low throughput.   We have developed a technique combining electrodeposition of electrodes with lithographic-scale resolution with hot embossed thermoplastic microfluidic system.  This rapid, cost-effective approach allows for integration of 2D and 3D self-anchoring conformal electrodes.

3D conformal nickel microelectrodes embedded in polycarbonate with embossed microfluidics

3D conformal nickel microelectrodes embedded in polycarbonate with embossed microfluidics

Cross section of nickel microelectrodes embossed in polycarbonate demonstrating self-anchoring "hook" shape and planar exposed surface

Cross section of nickel microelectrodes embossed in polycarbonate demonstrating self-anchoring "hook" shape and planar exposed surface

Our solvent-vapor assisted thermal bonding process completes the fabrication cycle for polycarbonate devices with embedded structures.

Water colored with blue dye passed over the nickel microelectrodes in a completed device

Water colored with blue dye passed over the nickel microelectrodes in a completed device