Thermoplastic polyurethane-based flexible multilayer microfluidic devices

Background: Microfluidics has been widely used in the biological and medical fields, and polymers are the most widely used materials in microfluidics at present due to their low cost and ease of processing. Both thermoplastics and thermosets were used as the bulk materials in microfluidics. The third option of a material with both advantages from thermoplastics and thermosets will be of great significance. Aim: We try to establish a low cost and rapid fabrication approach for thermoplastic polyurethane (TPU)-based microfluidics. Several demonstrations were also provided with the proposed fabrication method for TPU-based microfluidics. Approach: A CO2 laser ablation instrument was used for the fabrication of the TPU-based microfluidic devices. The width and depth of microchannels fabricated with various laser scan speeds and energies were studied in detail. For sealing the fabricated channels, a thermal fusion bonding method was also proposed with the bonding strength testing. Several types of the most commonly used microfluidic chips were fabricated for demonstration of the proposed fabrication method. Results: A comprehensive fabrication approach for TPU-based microfluidic devices was achieved. A series of microfluidic chips were designed, fabricated, and tested. Conclusions: TPU-based microfluidics is achievable and could be used as an alternative material for polydimethylsiloxane or thermoplastics for the fabrication of microfluidic devices. The proposed method could have broad potential applications in biological and chemical fields.