3D printed high density, reversible, chip-to-chip microfluidic interconnects

Abstract

Our latest developments in miniaturizing 3D printed microfluidics [Gong et al., Lab Chip, 2016, 16, 2450; Gong et al., Lab Chip, 2017, 17, 2899] offer the opportunity to fabricate highly integrated chips that measure only a few mm on a side. For such small chips, an interconnection method is needed to provide the necessary world-to-chip reagent and pneumatic connections. In this paper, we introduce simple integrated microgaskets (SIMs) and controlled-compression integrated microgaskets (CCIMs) to connect a small device chip to a larger interface chip that implements world-to-chip connections. SIMs or CCIMs are directly 3D printed as part of the device chip, and therefore no additional materials or components are required to make the connection to the larger 3D printed interface chip. We demonstrate 121 chip-to-chip interconnections in an 11 × 11 array for both SIMs and CCIMs with an areal density of 53 interconnections per mm and show that they withstand fluid pressures of 50 psi. We further demonstrate their reusability by testing the devices 100 times without seal failure. Scaling experiments show that 20 × 20 interconnection arrays are feasible and that the CCIM areal density can be increased to 88 interconnections per mm. We then show the utility of spatially distributed discrete CCIMs by using an interconnection chip with 28 chip-to-world interconnects to test 45 3D printed valves in a 9 × 5 array. Each valve is only 300 μm in diameter (the smallest yet reported for 3D printed valves). Every row of 5 valves is tested to at least 10 000 actuations, with one row tested to 1 000 000 actuations. In all cases, there is no sign of valve failure, and the CCIM interconnections prove an effective means of using a single interface chip to test a series of valve array chips.

Microchip electrophoresis separation of a panel of preterm birth biomarkers

“…Second, we used a 4% PEGDA solution: we found that 3% PEGDA was not sufficient to eliminate the undesired migration of analyte while 5% PEGDA tended to block the channels and prevent fluid flow. While these COC devices are compatible with standard 2D micromachining, we note that it is also feasible to 3D print microfluidic devices from PEGDA [37][38][39]. These 3D printed devices may be appealing for future analyses to avoid this photografting step.…”

Microfluidic multipoles theory and applications

“…The current resolution of commercial 3D printing technologies limits the integration of large numbers of connectors and multiplexers. However, custom 3D printer and resin 42 have been made demonstrating the integration of 88 connectors per mm 2 , with a feature resolution <20 μm 43,44 , which could allow making MFM with higher resolution and higher density applications, and serve many more applications in the life sciences.…”

3D Printed Microfluidic Features Using Dose Control in X, Y, and Z Dimensions

“…For our printer and this resin, surface roughness has previously been characterized using optical profilometry with prints at various exposure times [ 22 ]. For all exposure times tested (600–1200 ms), the RMS surface roughness was less than 100 nm, typically 55–60 ± 15 nm.…”

“…Our group has developed an SLA 3D printer, as well as a custom resin formulated specifically for creating truly microfluidic structures with this printer [ 20 ], and we have made small (18 × 20 µm) microfluidic channels [ 21 ], as well as fluid control systems involving pumps and valves [ 22 ]. To make the smallest channels, an edge compensation technique was employed which overexposed the pixels at the channel edge to make it narrower [ 21 ].…”