Flexible fluidic microchips based on thermoformed and locally modified thin polymer films

Abstract

This paper presents a fundamentally new approach for the manufacturing and the possible applications of lab on a chip devices, mainly in the form of disposable fluidic microchips for life sciences applications. The new technology approach is based on a novel microscale thermoforming of thin polymer films as core process. The flexibility not only of the semi-finished but partly also of the finished products in the form of film chips could enable future reel to reel processes in production but also in application. The central so-called 'microthermoforming' process can be surrounded by pairs of associated pre- and postprocesses for micro- and nanopatterned surface and bulk modification or functionalisation of the formed films. This new approach of microscale thermoforming of thin polymer film substrates overlaid with a split local modification of the films is called 'SMART', which stands for 'substrate modification and replication by thermoforming'. In the process, still on the unformed, plane film, the material modifications of the preprocess define the locations where later, then on the spatially formed film, the postprocess generates the final local modifications. So, one can obtain highly resolved modification patterns also on hardly accessible side walls and even behind undercuts. As a first application of the new technology, we present a flexible chip-sized scaffold for three dimensional cell cultivation in the form of a microcontainer array. The spatially warped container walls have been provided with micropores, cell adhesion micropatterns and thin film microelectrodes.

Hot embossing of high performance polymers

“…A suitable combination is for example PMMA or PC as thick layer and LCP or PEEK as thin layer which will be formed by the hot embossing process. In general the thermoforming of polymer foils bases on the application of gas pressure in a temperature range near the softening range of the polymer (Throne 2008;Truckenmüller et al 2008;Heilig et al 2010). By the combination of hot embossing and thermoforming the forming of the foil is effected by the polymer melt instead of gas pressure.…”

Microfluidic Chips for Point‐of‐Care Immunodiagnostics

“…[ 70 ] Microporous thermoformed polymer fl exible microfl uidic chips have been produced using hot embossing. [ 71 ] Tapered channels are produced using diffuse ultraviolet light [ 72 ] or laser ablation and integrated into a threedimensional microfl uidic chip. [ 73 ] Complex multilevel microchannels are fabricated using three-dimensional photoresist masters.…”

Technology of microthermoforming of complex three-dimensional parts with multiscale features

“…Microthermoforming of thin polymer films, with local surface modifications, was described by Giselbrecht et al (2006). This approach of microscale thermoforming of thin polymer film substrates overlaid with a split local modification of the films is called 'SMART', which stands for 'substrate modification and replication by thermoforming' (Truckenmüller et al 2008). Geometrical modifications of nanoscale surface modifications due to uniaxial and biaxial stretching of the polymer film are measured, described, and compared with an analytical model by Heilig et al (2010).…”