Abstract
In the last decade, the fabrication of microfluidic chips was revolutionized by 3D printing. It is not only used for rapid prototyping of molds, but also for manufacturing of complex chips and even integrated active parts like pumps and valves, which are essential for many microfluidic applications. The manufacturing of multiport injection valves is of special interest for analytical microfluidic systems, as they can reduce the injection to detection dead volume and thus enhance the resolution and decrease the detection limit. Designs reported so far use radial compression of rotor and stator. However, commercially available nonprinted valves usually feature axial compression, as this allows for adjustable compression and the possibility to integrate additional sealing elements. In this paper, we transfer the axial approach to 3D-printed valves and compare two different printing techniques, as well as six different sealing configurations. The tightness of the system is evaluated with optical examination, weighing, and flow measurements. The developed system shows similar performance to commercial or other 3D-printed valves with no measurable leakage for the static case and leakages below 0.5% in the dynamic case, can be turned automatically with a stepper motor, is easy to scale up, and is transferable to other printing methods and materials without design changes.
Highlights
It simplifies manufacturing processes, and enables the usage of microfluidic systems for a wide range of applications by combining increased configurability with high economic efficiency, especially for the manufacturing of prototypes [1,3,4]
For the 3D printing of microfluidic valves, two core approaches exist: for applications that allow an implementation with 2/2 way valves or a combination thereof, there is a broad spectrum of developed mechanisms, including but not limited to 4D printing, and new methods tailored to specific applications are constantly being further developed
The first two sealing concepts, which do not use specific sealing elements, leaked immediately, even when no measurable pressure was applied. This observation was made regardless of the used printing technique and is caused by the rough surface of the 3D-printed parts which always leads to a small gap between rotor and stator, even if both parts are strongly compressed [21]. This result is consistent with reports from literature, where either lubricants like vaseline [20], teflon spray [19] or teflon wrap [21] were used or only the rotor was 3D-printed with an elastic PDMS stator that ensured sealing [18,28]
Summary
It simplifies manufacturing processes, and enables the usage of microfluidic systems for a wide range of applications by combining increased configurability with high economic efficiency, especially for the manufacturing of prototypes [1,3,4]. For the 3D printing of microfluidic valves, two core approaches exist: for applications that allow an implementation with 2/2 way valves or a combination thereof, there is a broad spectrum of developed mechanisms, including but not limited to 4D printing, and new methods tailored to specific applications are constantly being further developed. In applications where 2/2 way valves cannot be used, e.g., when connections between different channels are to be changed, the rotor-stator principle, which is utilized in many commercial valves, is employed: Morioka et al developed a 3D-printed stator in combination with a polydimethylsiloxane (PDMS) microfluidic chip and improved the response time and minimized band-broadening effects in a flow injection analysis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
