Research highlights: microfluidically-fabricated materials

Abstract

Polymer particles with precise shapes or chemistries are finding unique uses in a variety of applications, including tissue engineering, drug delivery, barcoding, and diagnostic imaging. Microfluidic systems have been and are continuing to play a large role in enabling the precision synthesis of designer particles in a uniform manner. To expand the impact of these microfluidic-fabricated materials additional fundamental capabilities should still be developed. The capability to fabricate microparticles with complex three-dimensional shapes and increase the production rate of particles to an industrial scale will allow evaluation of shaped particles in a range of new applications to enhance biological, magnetic, optical, surface wetting, as well as other interfacial or mechanical properties of materials. Here we highlight work applying large collections of simple spherical microgels, with unique surface chemistry that allows in situ particle-particle annealing, to form microporous injectable scaffolds for accelerated tissue regeneration. We also report on two other techniques that are addressing the ability to create 3D-shaped microparticles by first sculpting a fluid precursor stream, and increasing the rate of production of particles using contact lithography to millions of particles per hour. The combination of these capabilities and the applications they will enable suggest a bright future for microfluidics in making the next materials.

Low voltage driven surface micro-flow by Joule heating

“…Studies on wetting dynamics show a complicated process where the capillary and precursor diffusion play crucial roles. 27,28 Typically the wetting distance L increases with time as a power law L ¼ Dt c , where D is the prefactor and t is the time. According to different material systems used, c ranging from 1/10 to 1/2 is theoretically predicted and experimentally observed.…”

Optofluidics based lab-on-chip device forin situmeasurement of mean droplet size and droplet size distribution of an emulsion

“…Optofluidics is an emerging field wherein light and fluids are manipulated in synergy to develop novel tools and techniques for devising either tunable optical components or lab-on-chip bio-chemical sensors with enhanced sensitivity and adaptability [30,31]. Several optofluidic lab-on-chip devices have been implemented in recent years for various applications including single cell analysis [32], controlling liquid motion using light [33], sunlight based fuel-production [34], microfabrication [35] and flow cytometry [36]. In particular the microflow cytometry setup has been used for different applications including counting and studying biological cells [37], bacteria [38], cellular deoxyribonucleic acid (DNA) [39,40] and droplets [41,42].…”

Fabrication of microscale materials with programmable composition gradients

“…9,10 Among the various techniques used to fabricate CG μMs, microfluidics appears as one of the most promising, due to the excellent control of transport phenomena provided at these small scales, 11 and due to the possibility of engineering micro-materials. 12 Du et al were the first to fabricate CG μMs (100 μm × 1 mm × 1 cm) made of photo-or thermalcrosslinkable pre-polymers with gradients (along the longest dimensions) of different components ranging from molecules to cells. 13 Their ingenious microfluidic platform uses control of hydrodynamic dispersion at small scales to obtain gradients using alternating flows in microfluidic channels.…”