Laser based manufacturing of microfluidic device for particle manipulation

Lab-on-a-chip (LOC) technology is widely used in various fields such as life sciences, material science, environmental monitoring, and chemical analysis [1]. These devices are increasingly preferred due to their superior functionality that allows for miniaturization, integration, and automation of various laboratory operations in a microfluidic platform. For a variety of diagnostic and clinical applications, manipulation of particles is a key requirement. Many techniques such as optical tweezers, chromatography, magnetophoresis, and electrophoresis have been so far used for this. Among these methods, Dielectrophoresis (DEP) [2] is gaining considerable interest for manipulating particles in microscale system, thanks to its favourable scalability for the reduced size of the system.

[1] Abgrall, P., and A. M. Gue. "Lab-on-chip technologies: making a microfluidic network and coupling it into a complete microsystem—a review." Journal of micromechanics and microengineering 17.5 (2007): R15.
[2] Çetin, Barbaros, and Dongqing Li. "Dielectrophoresis in microfluidics technology." Electrophoresis 32.18 (2011): 2410-2427.
[3] Scott, Simon M., and Zulfiqur Ali. "Fabrication methods for microfluidic devices: An overview." Micromachines 12.3 (2021): 319.
[4] Wlodarczyk, Krystian L., et al. "Rapid laser manufacturing of microfluidic devices from glass substrates." Micromachines 9.8 (2018): 409.


Dielectrophoresis is initiated by applying a non-uniform electric field, to manipulate the particle’s motion based on the interaction between its dipole moment and the electric field gradient. Conventionally, the microfluidic chip and the electrodes are fabricated using a combination of photolithography, soft lithography, hot embossing, injection moulding and thin-film deposition techniques (sputtering/thermal evaporation) [3]. These techniques have their own drawbacks on top of collectively being time-consuming and not cost-effective.

In this work, we use laser-based processes such as laser-induced forward transfer (LIFT), micromachining and micro-welding [4] to fabricate a fully functional microfluidic device for DEP application. Glass plates of thickness 1 mm are used as substrates, titanium electrodes are deposited using LIFT on plate 1 (fig.1a), micro-fluidic patterns and the inlet/outlet ports are machined on plate 2 (fig.1b), and the two plates are welded together (fig.1c) to form the sealed microfluidic device.