3D printed microfluidic
The Phantom Brain - A new tool in the toolbox of neurological research
We are developing new methods for creating flow devices in silicone rubber by using 3D printing techniques. Here we demonstrate the capability of our method by recreating the cerebral vascular network as a patient-specific phantom model. This technology can help advance research in the field of e.g. neurological disorders by allowing invasive measurement techniques not previously possible when working on patients. This work is explained in-depth in an upcoming paper...
3D printed water-soluble scaffolds for rapid production of PDMS micro-fluidic flow chambers
We report a novel method for fabrication of three-dimensional (3D) biocompatible micro-fluidic flow chambers in polydimethylsiloxane (PDMS) by 3D-printing water-soluble polyvinyl alcohol (PVA) filaments as master scaffolds. The scaffolds are first embedded in the PDMS and later residue-free dissolved in water leaving an inscription of the scaffolds in the hardened PDMS. We demonstrate the strength of our method using a regular, cheap 3D printer, and evaluate the inscription process and the channels micro-fluidic properties using image analysis and digital holographic microscopy. Furthermore, we provide a protocol that allows for direct printing on coverslips and we show that flow chambers with a channel cross section down to 40 μm × 300 μm can be realized within 60 min. These flow channels are perfectly transparent, biocompatible and can be used for microscopic applications without further treatment. Our proposed protocols facilitate an easy, fast and adaptable production of micro-fluidic channel designs that are cost-effective, do not require specialized training and can be used for a variety of cell and bacterial assays. Paper can be downloaded here: https://www.ncbi.nlm.nih.gov/pubmed/29463819
The effect of heating on channel shape, optical transparency and surface roughness.
The figure shows: (a) Cross section of an untreated channel scaffold entirely embedded in PDMS. (1) We attribute the pancake-stack geometry of the flow channel to the printing properties of our 3D printer. (2) Due to the mentioned irregularities in shape, the optical transparency of the flow chamber is only moderate, since black lines, wavy structures and air bubbles are visible in the image background. (3) Surface roughness of the channel created by an untreated channel scaffold. The discrete movement of the printer nozzle and inhomogeneous plastic extrusion appear as sinusoidal irregularities superimposed by high-frequency noise on the channel surface profile. (b) Channel cross section of a PDMS flow chamber with a coverslip as bottom layer. Heating the printed channel scaffold remelts the plastic, resulting in (1) a semi-elliptical channel shape with (2) excellent optical transparency. (3) Surface roughness of the heat-treated channel. Due to heating, only the sinusoidal irregularities from the step-like movement of the printer nozzle remains, improving the optical transparency significantly
