Freeform Microfluidic Networks Encapsulated in Laser‐Printed 3D Macroscale Glass Objects

Abstract

and fine chemical industries. [1][2][3][4][5][6] As a core element of microfluidic technology, high-performance fabrication of hollow microchannels with freeform geometries is crucial for further developing innovative microfluidic technology. In particular, extension of the microfluidic networks from widely used 2D to 3D configurations has now been considered as a promising scheme to enhance the performance of manipulation of fluids such as high-efficiency mixing, separation, and detection. [7][8][9][10][11] Fused silica is one of the widely used substrates for the microfluidic technology in laboratory research and industrial applications due to its high melting point, high chemical stability, low thermal expansion coefficient, wide transmission spectral range, and good biocompatibility. However, fabrication of freeform 3D hollow microchannels in fused silica is still difficult for current 2D fabrication techniques in terms of complex and tedious fabrication procedures, additional costs for aligning, stacking, and bonding steps. [12][13][14] Currently, one of the most representative 3D microfabrication techniques of fused silica is ultrashort pulse laser microfabrication. [15][16][17][18][19][20] A suspended hollow microchannel structure with a 3D controllable configuration can be fabricated in a way of either laser-assisted selective wet etching [21][22][23] or liquid-assisted laser ablation. [24][25][26] In addition, suspended hollow structures with 3D shapes and a high precision in fused silica can be fabricated by combining room-temperature casting and sacrificial template replication. [27] Meanwhile, 3D printing of glass materials emerging in recent years brings some new opportunities for scalable fabrication of freeform glass structures by either additive manufacturing strategies [28][29][30][31][32][33] or laser subtractive processing methods. [34][35][36] However, controllable formation of freeform hollow microchannel with arbitrary length encapsulated in 3D printed glass structures has not yet been demonstrated, which is highly desirable for high-infidelity manufacturing of artificial organs, on-chip construction of biomimetic microenvironments, [37][38][39][40][41] as well as enrichment of the functions of continuous-flow microreactors (e.g., seamless integration of customized functional module for temperature control and on-line spectrometer monitoring). [42,43] Especially, simultaneous fabrication of 3D embedded hollow microchannels with high aspect ratios and centimeter-scale glass objects with external arbitrary shapes on/in a single substrate still Large-scale microfluidic microsystems with complex 3D configurations are highly in demand by both fundamental research and industrial application, holding the potentials for fostering a wide range of innovative applications such as organ-on-a-chip as well as continuous-flow manufacturing. However, freeform fabrication of such systems remains challenging for current fabrication techniques in terms of fabrication resolution, flexibility, and achievable foo...

Advanced Fabrication Techniques of Microengineered Physiological Systems

“…Traditional methods require mechanical molding of the hydrogel; while this laser-induced method allows for a mask-less high throughput patterning which shortens the typical fabrication process by 60% and allows for parallelization [53]. Meanwhile, a process was created that combines "ultrashort pulse laser-assisted chemical etching of glass, 3D laser subtractive glass printing, and carbon oxide laser-induced glass melting" to fabricate "freeform 3D microfluidic networks encapsulated in 3D printed glass macroscale objects" [54]. This method allows for a monolithic approach for fabricating 3D freeform encapsulated microchannels with 3D printed glass structures [54].…”

“…Meanwhile, a process was created that combines "ultrashort pulse laser-assisted chemical etching of glass, 3D laser subtractive glass printing, and carbon oxide laser-induced glass melting" to fabricate "freeform 3D microfluidic networks encapsulated in 3D printed glass macroscale objects" [54]. This method allows for a monolithic approach for fabricating 3D freeform encapsulated microchannels with 3D printed glass structures [54]. The hybrid process provides high precision at both the micro (tens of micrometers) and macro (several centimeters) scale in a simple and flexible monolithic process [54].…”

“…This method allows for a monolithic approach for fabricating 3D freeform encapsulated microchannels with 3D printed glass structures [54]. The hybrid process provides high precision at both the micro (tens of micrometers) and macro (several centimeters) scale in a simple and flexible monolithic process [54]. It also allows for controllable sealing of ports and chemical inertness compared to other fabrication methods which often rely upon poly(dimethylsiloxane) (PDMS) [54].…”

“…The hybrid process provides high precision at both the micro (tens of micrometers) and macro (several centimeters) scale in a simple and flexible monolithic process [54]. It also allows for controllable sealing of ports and chemical inertness compared to other fabrication methods which often rely upon poly(dimethylsiloxane) (PDMS) [54]. Laser machining has also been used to create patterned adhesive film-based microfluidic devices [55][56][57].…”

High-Throughput Continuous-Flow Separation in a Micro Free-Flow Electrophoresis Glass Chip Based on Laser Microfabrication

“…In this paper, a facile method for fabricating a high-throughput μFFE chip based on femtosecond (fs) laser-assisted chemical etching of glass is demonstrated. Based on the combination of merits of ultrafast laser-glass nonlinear interaction and selective chemical etching of glass, fs laser-assisted chemical etching of glass enables the versatile fabrication of 3D glass microstructures with nearly arbitrary configurations [22][23][24][25][26]. To isolate the separation chamber and electrode channels, two microchannel arrays are introduced, which can be simultaneously fabricated with other microfluidic components through fs laser microfabrication.…”