Shrink film patterning by craft cutter: complete plastic chips with high resolution/high-aspect ratio channel

Abstract

This paper presents a rapid, ultra-low-cost approach to fabricate microfluidic devices using a polyolefin shrink film and a digital craft cutter. The shrinking process (with a 95% reduction in area) results in relatively uniform and consistent microfluidic channels with smooth surfaces, vertical sidewalls, and high aspect ratio channels with lateral resolutions well beyond the tool used to cut them. The thermal bonding of the layers results in strongly bonded devices. Complex microfluidic designs are easily designed on the fly and protein assays are also readily integrated into the device. Full device characterization including channel consistency, optical properties, and bonding strength are assessed in this technical note.

Unconventional Low-Cost Fabrication and Patterning Techniques for Point of Care Diagnostics

“…3). 16,84 The functionality of the chip was assessed by performing a sandwich immunoassay within the device and the results showed an increase in fluorescence intensity post-shrinkage. Sollier et al utilized “Print-n-Shrink” technology to fabricate their microfluidic devices.…”

Rapid bench-top fabrication of poly(dimethylsiloxane)/polystyrene microfluidic devices incorporating high-surface-area sensing electrodes

“…Some of the uses for these materials include reducing the size of microfluidic channels and patterned surfaces, 21,22 and structuring thin films through compressive stress. 16,23,24 Our group 15,25 and others 20,26,27 have used the latter approach to structure gold films with features that are tuneable in the micro-to nanoscale.…”

Shrink-film microfluidic education modules: Complete devices within minutes

“…29,30 For ease of handling, 1 mil thick prestressed polyolefin shrink-film ͑Sealed Air Nexcel multilayer shrink-film 955D, USA͒ was laminated onto a 3 mil thick nonshrinkable polyester backing. 30,44 During the printing process, ink was deposited onto this prestressed polyolefin film on the polyester backing. For structural support during the printing process, the polyolefin film and polyester backing should be taped onto a flat sheet of paper ͓Fig.…”

“…30,42 In our previous efforts, we have leveraged printing and etching prestressed polystyrene and polyolefin ͑PO͒, which retracted in-plane by approximately 60% and 95%, respectively. 29,30,[42][43][44] This strategy allows for rapid fabrication of high-aspect micromolds, which can be used for standard soft lithography, negating the use of expensive patterning tools and microfabrication infrastructure. Importantly, this technique improves upon the printed resolution as the features shrink with the retracting substrate.…”

“…Next, channels were then washed with 1xPBS and filled with 1 mg/ml of bovine serum albumin blocking solution for 1 h to prevent nonspecific binding of secondary antibodies. 44 It should be noted that for the loading of primary antibody and rinsing steps, generation of a gradient was not necessary. For the loading of secondary antibody, channels were then filled as a gradient with one inlet containing 50 g / ml secondary antirabbit IgG conjugated fluorophore and the other inlet containing 1xPBS at a steady flowrate of 30 L / h. In this procedure, the high flowrate of 30 L / h minimizes the chances of backflow and upstream mixing that might induce gradients in the five channels.…”