Rapid prototyping of microfluidic channels in nitrocellulose using laser-direct-write patterning

He, P., Katis, I.N., Eason, R.W. and Sones, C.L. (2015) Rapid prototyping of microfluidic channels in nitrocellulose using laser-direct-write patterning. SPIE Photonics West - Microfluidics, BioMEMS, and Medical Microsystems XIII, San Francisco, United States. 07 - 12 Feb 2015.

Abstract

The demand for low-cost alternatives to conventional point-of-care (POC) diagnostic tools has led to significant developments in the field of microfluidics in porous paper. Several approaches have already been reported for fabricating fluidic devices in such materials, which include photolithography, inkjet printing, printing of wax, plasma oxidation, laser-cutting, and shaping. Nitrocellulose is a particularly important material that is routinely used in lateral-flow type medical diagnostic tests used in POC environments.

Here, we report the patterning of microfluidic structures in porous nitrocellulose through a simple laser-direct-write (LDW) procedure, which relies on light-induced photo-polymerisation of a photopolymer previously impregnated in the nitrocellulose membranes. During the subsequent development step, the un-polymerised photopolymer is removed, while the polymerized structures remain. These resulting hydrophobic structures extend throughout the thickness of the nitrocellulose and form the barrier-walls of the interconnected hydrophilic fluidic patterns they demarcate. Analysis showed that these structures can contain and guide the flow of liquids without any leakage, and hence this technique can be used to produce an array of microfluidic devices for many applications such as clinical diagnostics and analytical chemistry. Our results show that the smallest dimensions that can be achieved for hydrophobic barrier-walls and microfluidic channels using this method are ~ 60 µm and ~ 100 µm respectively, both of which are the smallest values reported so far for fabrication of nitrocellulose-based microfluidic devices. In addition, the process steps for this LDW process are compatible for roll-to-roll processing, which would lead to device production on a commercial-scale.

This record has no associated files available for download.

Contributors

Author: I.N. Katis

Author: R.W. Eason

Download statistics