Polymeric fully inertial lab-on-a-chip with enhanced-throughput sorting capabilities

Abstract

In biology and medicine, the application of microfluidics filtration technologies to the separation of rare particles requires processing large amounts of liquid in a short time to achieve an effective separation yield. In this direction, the parallelization of the sorting process is desirable, but not so easy to implement in a lab on a chip (LoC) device, especially if it is fully inertial. In this work, we report on femtosecond laser microfabrication (FLM) of a poly(methyl methacrylate) (PMMA) inertial microfluidic sorter, separating particles based on their size and providing an enhanced-throughput capability. The LoC device consists of a microchannel with expansion chambers provided with siphoning outlets, for a continuous sorting process. Different from soft lithography, which is the most used technique for LoC prototyping, FLM allows developing 3D microfluidic networks connecting both sides of the chip. Exploiting this capability, we are able to parallelize the circuit while keeping a single output for the sorted particles and one for the remaining sample, thus increasing the number of processed particles per unit time without compromising the simplicity of the chip connections. We investigated several device layouts (at different flow rates) to define a configuration that maximizes the selectivity and the throughput.

Inertial microfluidics: Recent advances

“…With this modification, the continuous separation of PS particles with a high size‐selectivity of <2 μm, a high efficiency of ∼90%, and a high purity of >90% was realized. Moreover, further improvements including a multimodal separation with a high tunability of separation cutoff diameters [161,162], and the enhanced‐throughput sorting capabilities by developing 3D microfluidic networks [163] were reported.…”

Sorting of Particles Using Inertial Focusing and Laminar Vortex Technology: A Review

“…In order to avoid the expensive and time-consuming production of masks and the necessity of a clean room, femtosecond-laser micromachining technology (FLM) for the rapid prototyping of inertial sorting LoCs has been developed [83]. Thanks to the short timescale which characterizes the energy deposition during femtosecond-laser irradiation, material is removed with a negligible heat-affected zone, thus allowing micro-milled features with high precision and resolution [84] to be created.…”

“…The work of Volpe et al [83] aimed at improving the throughput of previous implementations, while keeping the sorting efficiency high. In particular, the micro-fluidic devices presented in [83] consisted of micro-channels with expansion chambers in series.…”

“…The work of Volpe et al [83] aimed at improving the throughput of previous implementations, while keeping the sorting efficiency high. In particular, the micro-fluidic devices presented in [83] consisted of micro-channels with expansion chambers in series. Partially inspired from the work of Wang and Papautsky [88], the chambers were supplied with siphoning outlets exiting from the backside of the chip.…”

Study of Local Inertial Focusing Conditions for Spherical Particles in Asymmetric Serpentines

“…Inertial focusing positions are inherently dependent on particle's physical properties (its size, shape and deformability [10][11][12][13]). Particularly, both theoretical and experimental approaches have found a strong relationship between the particle's diameter and the inertial lift [14][15][16][17][18][19][20]. This fact and other physical particularities of cells and particles (like size, rigidity and shape) are further exploited to separate cells and particles in a passive manner according to these properties to either sort them, enrich a particular sub-population [21][22][23][24][25][26][27][28][29], perform a solution reduction of a sample (volume reduction) [30][31][32] or a solution exchange in a sample containing cells (RInSE) [33,34].…”