A low-cost, composite collagen-PDMS material for extended fluid retention in the skin-interfaced microfluidic devices

• Published in: Colloid and interface science communications Vol. 38; p. 100301
• Main Authors: Heo, Benjamin, Fiola, Michael, Yang, Ji Hyun, Koh, Ahyeon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2020
• Subjects: Collagen microparticle; PDMS composite; Sweat collection; Water permeability; PDMS composite; Sweat collection; Collagen microparticle; Water permeability
• ISSN: 2215-0382; 2215-0382
• DOI: 10.1016/j.colcom.2020.100301

The advancement of soft, wearable microfluidic devices relies on the microfabrication of polydimethylsiloxane (PDMS) using soft lithography techniques. However, thin 3D microstructures made of PDMS limit long-term storage of aqueous samples and reduce the accuracy of onboard sensing modalities within the platform because of the material's high permeation of water vapor. We studied a composite material of collagen microparticles and PDMS that greatly reduces water evaporation while maintaining the properties of a soft elastomer required for skin-interfaced microfluidics. The collagen-PDMS material is biocompatible, affordable, and non-toxic. We reduced permeability by 80.2% by building a film containing 30 wt% collagen microparticles. Mechanical properties, such as elastic modulus and bonding efficacy, can vary as a function of particle concentration in the films. The skin-interfaced collagen-PDMS microfluidic devices increase sweat retention by 45% through 9 h compared with pure PDMS. This material can greatly improve the long-term sample storage of epidermal devices. [Display omitted] •Collagen microparticles embedded elastomeric microfluidics exhibiting low water vapor permeability.•Long-term storage of biofluids in the skin-interfaced microfluidic sensing system.•Economically affordable, soft-lithographically defined, fast prototyping soft biosensing system.