Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. By applying a slow curing process, we show that biomolecules can be incorporated via a simple process as liquid stable phases inside a polydimethylsiloxane PDMS matrix.
The process is carried out under mild conditions with regards to temperature, pH and relative humidity, and is thus suitable for application to biological entities. Fluorescence and enzymatic activity measurements show that the biochemical properties of the proteins and enzyme tested are preserved, without loss due to adsorption at the liquid-polymer interface.
Protected from external stimuli by the PDMS matrix, these soft liquid composite materials are new tools of interest for robotics, microfluidics, diagnostics and chemical microreactors. Liquids and elastomeric materials are key components in microfluidic and diagnostic devices.
Conveyed in open structures such as microchannels 1 , deposited as refillable reservoirs 2 , or conductive metallic lines 3 , liquids can add novel functionalities to materials. For instance, in closed structures such as droplets, liquids reinforce the mechanical properties of elastomeric composite material 4. Our work reports a novel inclusion process and addresses how it affects the molecules contained in the droplets, in particular bioactive molecules or particles embedded in a polydimethylsiloxane PDMS matrix.
The introduction of compartments, channels and cages in materials is a challenging, yet desired step towards the manufacture of complex lab-on-a-chip architectures, metamaterials 5 , flexible sensors 6 , stretchable electronics 3 , soft composites 7 , mobile structures 8 , and soft robots 9. When coupled to a high-throughput manufacturing strategy, this allows access to a large number of samples, each with different reaction conditions For instance, this has been used for screening and for crystallization studies, where nanoliter-scale droplets have been superficially deposited on a PDMS chip to imprint nanowells A similar approach has been applied to single protein counting 12 and single-cell analyses 13 , Single size-controlled droplets provide microreactors for chemical reactions in a partially isolated environment, which is of high interest for microfluidic devices 16 , 17 , 18 , or the analysis of reactions in confined spaces The inclusion of a liquid or gel phase in a polymeric material allows modification of the mechanical properties of the material and the generation of soft liquid composites SLC with novel properties and functionalities, e.
