Reaction injection molding of hydrophilic-in-hydrophobic femtolitre-well arrays

Abstract

Patterning of micro- and nanoscale topologies and surface properties of polymer devices is of particular importance for a broad range of life science applications, including cell-adhesion assays and highly sensitive bioassays. The manufacturing of such devices necessitates cumbersome multiple-step fabrication procedures and results in surface properties which degrade over time. This critically hinders their wide-spread dissemination. Here, we simultaneously mold and surface energy pattern microstructures in off-stoichiometric thiol-ene by area-selective monomer self-assembly in a rapid micro-reaction injection molding cycle. We replicated arrays of 1,843,650 hydrophilic-in-hydrophobic femtolitre-wells with long-term stable surface properties and magnetically trapped beads with 75% and 87.2% efficiency in single- and multiple-seeding events, respectively. These results form the basis for ultrasensitive digital biosensors, specifically, and for the fabrication of medical devices and life science research tools, generally.

Simultaneous microstructuring and surface modification of microfluidic bioreactors

Researchers from Sweden and Belgium have developed a simplified technique to create microfluidic devices with patterns of modified surface properties. Microfluidic devices, such as the one demonstrated here by a team led by Wouter van der Wijngaart, from KTH Royal Institute of Technology, Sweden, utilize polymer microstructures with hydrophobic and hydrophilic properties to manipulate fluids on a tiny scale. This enables ‘lab-on-a-chip’ experiments with a diverse array of applications. However, current devices suffer from complicated fabrication processes and a limited lifespan. van der Wijngaart and his team used the polymer ‘off-stoichiometric thiol-ene’ to merge a rapid replication technique called reaction injection molding with a method to self-assemble hydrophobic and hydrophilic micropatterns in a single, rapid fabrication step. The researchers hope that their results will form the basis for future microfluidic chip manufacturing and lead to the creation of ultrasensitive life science research tools.