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3D-printing and microfluidics

A B

C

Figure 3. Three-dimensional (3D)-printed modular microfluidics. (A) Individual microfluidic module. (B) A microfluidic droplet generator
is constructed by cascading three 3D-printed modules. (C) Several complex 3D microfluidic configurations constructed from 3D-printed
microfluidic modules. Reproduced from Ref. Bhargava et al. with permission from the National Academy of Science (US). Copyright
[39]
(2015) National Academy of Sciences.

3D-printing also shortens the time required from design technologies, such as 3D-printing, are not in demand, but
to fabrication, providing a valuable rapid prototyping these new technologies must bring new values and fulfill
tool for microfluidic devices. But has microfluidics requirements dictated by the applications.
truly benefited from these innovations? Since the first In spite of its many compelling advantages, 3D-printing
demonstration of the microfluidics-based “lab on a chip” faces unique problems that may hinder its applicability in
in the 1990s, microfluidics has made a significant process. microfluidics for high-value applications.
Nowadays, microfluidics is already a mature technology One of such problems is the limited printer resolution,
that enjoys its prosperity in biomedical fields. The particularly in the lateral direction. The lateral resolution
research emphasis on microfluidics has gradually shifted of a 3D-printer is determined by the minimal line width
from the device fabrication techniques, the fundamental generated in a single pass, and the vertical resolution
physics of fluidic behaviors, and fluidic actuation and is determined by the minimal thickness of each layer.
sensing mechanisms, to high-value applications, such The extrusion-based printers, such as FDM, have a
as large-scale single-cell/molecule analysis for genomic lateral resolution of hundreds of microns and a vertical
and proteomic studies as well as sample-to-answer total resolution of tens of microns. The resolution of liquid
analysis for point-of-care diagnostics . Therefore, any resin-based printers, such as SLA and inkjet, has a lateral
[1]
present and future development in microfluidics ought to resolution of tens of microns and a vertical resolution
be oriented toward specific applications for high scientific of down to single-digital microns . (Although 2PP is
[44]
and social impact. That is not to say new fabrication also a liquid resin-based 3D-printing technology, it is a
66 International Journal of Bioprinting (2019)–Volume 5, Issue 2