Droplet microreactor for high-throughput fluorescence-based measurements of single catalyst particle acidity.

The particles of heterogeneous catalysts differ greatly in size, morphology, and most importantly, in activity. Studying these catalyst particles in batch typically results in ensemble averages, without any information at the level of individual catalyst particles. To date, the study of individual catalyst particles has been rewarding but is still rather slow and often cumbersome.

Autonomous capillary microfluidic devices with constant flow rate and temperature-controlled valving.

In this paper, we report on a capillary microfluidic device with constant flow rate and temperature-triggered stop valve function. It contains a PDMS channel that was grafted by a thermo-responsive polymer poly(N-isopropylacrylamide) (PNIPAm). The channel exhibits a constant capillary filling speed.

Safety of electrooxidation for urea removal in a wearable artificial kidney is compromised by formation of glucose degradation products.

A major challenge for the development of a wearable artificial kidney (WAK) is the removal of urea from the spent dialysate, as urea is the waste solute with the highest daily molar production and is difficult to adsorb. Here we present results on glucose degradation products (GDPs) formed during electrooxidation (EO), a technique that applies a current to the dialysate to convert urea into nitrogen, carbon dioxide, and hydrogen gas. Uremic plasma and peritoneal effluent were dialyzed for 8 hours with a WAK with and without EO-based dialysate regeneration.

Single catalyst particle diagnostics in a microreactor for performing multiphase hydrogenation reactions.

Since inter- and intra-particle heterogeneities in catalyst particles are more the rule than the exception, it is advantageous to perform high-throughput screening for the activity of single catalyst particles. A multiphase system (gas/liquid/solid) is developed, where droplet-based microfluidics and optical detection are combined for the analysis of single catalyst particles by safely performing a hydrogenation study on in-house synthesized hollow Pd/SiO catalyst microparticles, in a polydimethylsiloxane (PDMS) microreactor. A two-phase segmented flow system of particle-containing droplets is combined with a parallel gas-reactant channel separated from the flow channel by a 50 μm thick gas permeable PDMS wall.

Luminescence thermometry for in situ temperature measurements in microfluidic devices.

Temperature control for lab-on-a-chip devices has resulted in the broad applicability of microfluidics to, e.g., polymerase chain reaction (PCR), temperature gradient focusing for electrophoresis, and colloidal particle synthesis.