3D printed selectable dilution mixer pumps

Abstract

In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al., Lab Chip 18, 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only 1:5 mm 3 and 2:6 mm 3 , respectively. The LDMP generates a selectable dilution ratio from a linear set of possibilities, while the PDMP generates a denser set of possible dilutions with a maximum dilution ratio of 1/16. The PDMP also incorporates a new 4-to-1 valve to simultaneously control 4 inlet channels. To characterize LDMP and PDMP operation and performance, we present a new, low-cost video method to directly measure the relative concentration of an absorptive dye on a pixel-by-pixel basis for each video frame. Using this method, we find that 6 periods of the active mixer that forms the core of the LDMP and PDMP are sufficient to fully mix the fluid, and that the generated concentrations track the designed dilution ratios as expected. The LDMP mixes 20 nl per 4.6 s mixer pump period, while the PDMP uses parallelized input pumps to process the same fluid volume with greater choice of dilution ratios in a 3.6 s period.

3D-Printed Microfluidic Droplet Generator with Hydrophilic and Hydrophobic Polymers

“…The limitations of these two categories of MFDs, high-resolution printing constrained to a single plane (pMFD) and the low-resolution printing of non-planar 3D microfluidic devices (npMFD), prompted the Nordin group to develop a high-resolution SLA printer and resin capable of manufacturing npMFDs with channel dimensions as small as 18 × 20 m [ 15 , 16 ]. Subsequent publications based on our custom-built non-planar 3D printing system have demonstrated microchannels, pumps, control valves and mixers—all within a matrix of biocompatible polymers [ 17 , 18 , 19 ]. One unit operation yet to be demonstrated in our system is that of droplet generation, which has been shown to be key to many microfluidic operations [ 1 , 2 , 3 , 4 , 5 , 6 ].…”

“…However, the aqueous droplet generation in this previous system was problematic because the PEG-acrylate resin was not sufficiently hydrophobic. In this paper, we present two developments by which droplet generators can be made in high-resolution npMFDs on the custom printer that we previously developed and demonstrated [ 15 , 16 , 17 , 18 , 19 , 25 ]. We first developed and characterized a novel hydrophobic resin by measuring the hydrophobic/hydrophilic properties and correlating these with the resin formulation that allows the formation of aqueous droplets (in oil) with any desired droplet generator geometry.…”

micrIO: an open-source autosampler and fraction collector for automated microfluidic input–output

“…[9][10][11] A flexible interface allowing samples in common labware formats to be introduced into and collected from microfluidic devices would help surmount the 'world-to-chip' barrier and make it possible for more laboratories to benefit from the full potential of on-chip automation. [12][13][14][15] Treating a microfluidic device as a processing module, this challenge can be described as microfluidic input-output (IO). Low-throughput, serial IO is easily handled through manual exchange of vessels connected to a device.…”

Three-Dimensional Printed Devices in Droplet Microfluidics

“…Electrical, thermal, magnetic, mechanical, pneumatic and acoustic control methods wereinvestigated in conventional droplet microfluidics and many excellent reviews have summarized related studies [36,59]. Recently some active components such as valves [85,88], pumps [86,87], and even classical Quake-style microvalves were successfully 3D printed [89], which demonstrated 3DP potentials in active control of droplets.…”