3D-Printed Microfluidic Devices for Enhanced Online Sampling and Direct Optical Measurements

Abstract

3D printing has emerged as a robust technique to fabricate reliable and reproducible microfluidic devices. However, a limitation of 3D-printed devices has been the low transparency even when printed in a "clear" material. There are currently no reports regarding direct optical measurements through a 3D-printed device. Here, we present for the first time that the printing orientation can affect the transparency of a 3D-printed object. With the optimal orientation, we printed a microfluidic detector that was sufficiently transparent (transmittance ≈ 80%) for optical quantitation. This finding is significant because it shows the feasibility to directly 3D-print optical components for analytical applications. In addition, we created a novel microfluidic dialysis device via 3D printing, which enabled higher flow rates (for sampling with high temporal resolution) and increased extraction efficiency than commercially available ones. By coupling the microfluidic detector and dialysis probe, we successfully measured the release kinetics of indole from biofilms in a continuous, automated, and near real-time fashion. Indole is an intercellular signaling molecule in biofilms, which may regulate antibiotic resistance. The release kinetics of this molecule had not been quantitated likely because of the lack of a suitable analytical tool. Our results fill this knowledge gap.

Study on the development and integration of 3D‐printed optics in small‐scale productions of single‐use cultivation vessels

“…As for this work a 3D-inkjet printer is used, which has a print head with a predefined trajectory. Therefore, it was also important to investigate the influence of the CAD-model orientation on the optical properties and consequently how parts should be placed on the plate [14]. Since deflection prisms have flat surfaces, one solution is to bond cover glasses to improve the reflective properties of the hypotenuse.…”

Emerging 3D printing technologies and methodologies for microfluidic development

“…However, our recent work has demonstrated a new method to optimize the transparency during printing. 68 Using a Projet MJP 5600 printer and VisiJet CR-CL 200 material, we demonstrated that by optimizing the printing orientation, the transparency of a part could be tuned. 68 Our results were based on the hypothesis that due to the stacking of the layers in the z -direction during printing as demonstrated in Fig.…”

“…68 Using a Projet MJP 5600 printer and VisiJet CR-CL 200 material, we demonstrated that by optimizing the printing orientation, the transparency of a part could be tuned. 68 Our results were based on the hypothesis that due to the stacking of the layers in the z -direction during printing as demonstrated in Fig. 7D, the sides of the part are rougher and less transparent.…”

“…It is an extrusion-based technique that dispenses melted lament layer by layer under controlled ow rates, until a full object is created 42 Less costly (few hundred US dollars) compared to other 3D printers 43 Signicant pore formation in 3D printed parts 46 Microuidic devices in PS with acceptable transparency 48 A technique of optimizing the printing orientation of an FDM printer to tune the mixing ability of a microuidic by changing the printing angle 56 Low resolution (hundreds of mm) 47 Transparent 3D printed devices that can allow ow rates up to 2 mL min À1 with no leakage 43 It can 3D print almost all thermoplastic polymers 44 A ow cell from optically opaque and transparent PLA 49 A 3D printed microuidic device for the synthesis of gold and silver nanoparticles 50 The transparency of FDM-based microuidic devices was improved by optimizing the properties of the printing nozzle 59 Minimal to no posprocessing 31 A 3D printed droplet microuidics for E. coli detection 51 It allows multi-material 3D printing in a single step 45 A multi-material microchip for capillary electrophoresis 53 Polyjet 3D printing A liquid photosensitive polymer and a supporting material are jetted from micronozzle arrays onto the platform area to build an object layer by layer 29 Faster than stereolithography 20 It requires a postprocessing step 29 A modular 3D printed cell culture microuidic device for 3D multicellular spheroids 64 A technology that could circumvent the need for a photocurable support material 63 High layer resolution (14 mm) 20 Very expensive (a hundred thousand US dollars) 20 A method of optimizing the transparency of a part during printing 68 It works with materials of different physical properties (rigid vs. exible) 62 An insert-based microuidic device for 3D cell cultures 65 It can mix materials at different ratios 61 A technology of combining 3D printed adapters and a microbore for optical detections 69 Suitable for complex geometries 57 A bacteria sensor containing a 3D-printed Ag + selective electr...…”

“…7F). 68 Using this detector, we were able to quantify the absorbance of a signaling molecule (indole) released from bacteria in near-real time. 68 To our knowledge, this was the first direct absorbance detection on a 3D printed part from a polyjet printer.…”