3D printed cell for the in situ dynamic light scattering monitoring of nanoparticle size distribution in microfluidics

Microfluidic systems offer a reproducible approach for material synthesis at microliter quantities. Automatization of such systems requires development of new approaches for in situ diagnostics, which can provide feedback for the optimization algorithms. The knowledge about size distribution at different reaction stages is of key importance for the nanoparticle synthesis, but most laboratory devices are designed to work with batch systems. In this work we have designed 3d printed devices for dynamic light scattering (DLS) characterization. The combination of backscatter DLS module and microfluidic chips enables in situ monitoring of ultra-low (down to nanoliters) volumes of sample solution even at high concentration. We report several types of microfluidic chips compatible with the commercially available systems with analyzer fiber probe for the measurements in flow and static regimes. The latter option does not contribute with the flow speed to the Brownian motion of nanoparticles and thus does not affect the calculated particle size distribution. 3d-printed cell for DLS measurements on the one hand, probes small sample volume, on the other, enables cheap in situ hydrodynamic size determination. The application of developed instruments is demonstrated for Tb-doped GdF3 nanoparticles, tween micelles, and gold nanoparticles.

Automated summary

In this study, we designed 3D printed devices for dynamic light scattering (DLS) characterization, which can provide in situ monitoring of size distribution in small sample solutions. This new approach allows for automated microfluidic synthesis and provides feedback for optimization algorithms.