ABSTRACT
Advances in the instrumentation and materials for photopolymerization 3D printing aided the use of this powerful technique in the fabrication of microfluidic devices. The costs of printers and supplies have been reduced to the point where this technique becomes attractive for prototyping microfluidic systems with good resolution. With all the development of multi-material 3D printers, most of the microfluidic devices prepared by photopolymerization 3D printing are based on a single substrate material. We developed a digital light processing multi-material 3D printer where two or more resins can be used to prepare complex objects and functional microfluidic devices. The printer is based on a vat inclination system and embedded peristaltic pumps that allow the injection and removal of resins and cleaning step between material changes. Although we have built the whole system, the modification can be incorporated into commercially available printers. Using a high-resolution projector, microfluidic channels as narrow as 43 µm were obtained. We demonstrate the printing of multi-material objects containing flexible, rigid, water-soluble, fluorescent, phosphorescent, and conductive (containing PEDOT or copper nanoparticles) resins. An example of a microfluidic chip containing electrodes for electrochemical detection is also presented.
ABSTRACT
The fabrication of microfluidic devices through fused deposition modeling (FDM) 3D printing has faced several challenges, mainly regarding obtaining microchannels with suitable transparency and sizes. Thus, the use of this printing system to fabricate microdevices for analytical and bioanalytical applications is commonly limited when compared to other printing technologies. However, for the first time, this work shows a systematic study to improve the potential of FDM 3D printers for the fabrication of transparent microfluidic devices. Several parameters and printing characteristics were addressed in both theoretical and experimental ways. It was found that the geometry of the printer nozzle plays a significant role in the thermal radiation effect that limits the 3D printing resolution. This drawback was minimized by adapting an airbrush tip (0.2 mm orifice diameter) to a conventional printer nozzle. The influence of the height and width of the extruded layer on the resolution and transparency in 3D-printed microfluidic devices was also addressed. Following the adjustments proposed, microchannels were obtained with an average width of around 70 µm ± 11 µm and approximately 80% visible light transmission (for 640 µm thickness). Therefore, the reproducibility and resolution of FDM 3D printing could be improved, and this achievement can expand the capability of this printing technology for the development of microfluidic devices, particularly for analytical applications.
Subject(s)
Lab-On-A-Chip Devices , Printing, Three-Dimensional , Drug Delivery Systems , Reproducibility of ResultsABSTRACT
In this study, we describe a proof-of-concept investigation of the potential and limitations of employing channel occlusion for sample preparation in untargeted analysis in petroleomics. A middle petroleum distillate composed of fatty acid methyl esters (FAME) and a complex mixture of linear, branched, and cyclic hydrocarbons were selected as the model samples for this investigation. A microfluidic device was engineered to overcome the limitations of channel occlusion, resulting in a quick and robust method for sample preparation. The 3D-printed device using fused deposition modelling (FDM) allowed the combination of a 13-h multi-step sample handling protocol into a 2-min single-step procedure, which is also automation-friendly. Such developments were also evaluated using the analytical eco-scale to guide the development of a green analytical method. The relative standard deviation decreased 2-fold with method miniaturization. The efficiency of n-alkane removal was extended from tridecane (n-C13) to heptadecane (n-C17), compared to original method (n-C16 to n-C17). The analytical performance of the method was investigated for untargeted analysis. The tool used to probe the intra- and inter-class variance was multi-way principal component analysis (MPCA). MPCA modelling revealed that both methods generated equivalent chemical information, highlighting the benefits of reliable and reproducible sample preparation methods, especially for untargeted analysis. Such awareness is critical to avoid the generation of misleading results in fields that heavily rely on untargeted analysis and fingerprinting, such as petroleomics.