Polyshrink™ based microfluidic chips and protein microarrays

Progress of shrink polymer micro- and nanomanufacturing

Traditional lithography plays a significant role in the fabrication of micro- and nanostructures. Nevertheless, the fabrication process still suffers from the limitations of manufacturing devices with a high aspect ratio or three-dimensional structure. Recent findings have revealed that shrink polymers attain a certain potential in micro- and nanostructure manufacturing. This technique, denoted as heat-induced shrink lithography, exhibits inherent merits, including an improved fabrication resolution by shrinking, controllable shrinkage behavior, and surface wrinkles, and an efficient fabrication process. These merits unfold new avenues, compensating for the shortcomings of traditional technologies. Manufacturing using shrink polymers is investigated in regard to its mechanism and applications. This review classifies typical applications of shrink polymers in micro- and nanostructures into the size-contraction feature and surface wrinkles. Additionally, corresponding shrinkage mechanisms and models for shrinkage, and wrinkle parameter control are examined. Regarding the size-contraction feature, this paper summarizes the progress on high-aspect-ratio devices, microchannels, self-folding structures, optical antenna arrays, and nanowires. Regarding surface wrinkles, this paper evaluates the development of wearable sensors, electrochemical sensors, energy-conversion technology, cell-alignment structures, and antibacterial surfaces. Finally, the limitations and prospects of shrink lithography are analyzed.

Preparation and validation of low cost microfluidic chips using a shrinking approach

The present paper describes the production of microfluidic chips using an approach based on shrinkable biocompatible polymers (i.e. agarose) for the production of size controlled microfluidic channels. In addition, all steps of chip production were carried out using an inexpensive approach that uses low cost chemicals and equipment. The produced chips were then validated by producing monodisperse polymeric microparticles for drug delivery and hydrogel microfibers for cell embedding.

Thermally-induced miniaturization for micro- and nanofabrication: progress and updates

The field of micro- and nanofabrication has developed extensively in the past several decades with rising interest in alternative fabrication techniques. Growth of these areas has been driven by needs that remain unaddressed by traditional lithographical methods: inexpensive, upscalable, biocompatible, and easily integrated into complete lab-on-a-chip (LOC) systems. Shape memory polymers (SMPs) have been explored as an alternative substrate. This review first focuses on structure fabrication at the micron and nanoscale using specifically heat-shrinkable SMPs and highlights the innovative improvements to this technology in the past several years. The second part of the review illustrates demonstrated applications of these micro- and nanostructures fabricated from heat-shrinkable SMP films. The review concludes with a discussion about future prospects of heat-shrinkable SMP structures for integration into LOC systems.

Shrinking hydrogel-DNA spots generates 3D microdots arrays

This report describes a straightforward approach for the achievement of sub-100 micrometers size hydrogel dots supporting DNA immobilization. Hydrogel-DNA spots are arrayed and UV-crosslinked on PolyShrink, an innovative polymer material having the remarkable property of isotropically shrinking under high temperature. Curing the microarray enables then spot miniaturization, resulting in 6 µm thick and 60 µm wide hydrogel dots in which oligonucleotides are immobilized in a 3D hydrophilic environment. The probe immobilization within the hydrogel network and its capacity to detect targets specifically and quantitatively is demonstrated using chemiluminescent as well as colorimetric detection techniques. The hydrogel material improves probe accessibility within the spot, leading to an enhanced sensitivity.