Three-dimensionally crossing manifold micro-mixer for fast mixing in a short channel length

Abstract

In this study, we report a neo-conceptive three-dimensionally (3D) crossing manifold micromixer (CMM) embedded in microchannel. Fabricated by sequential processes of photolithography and two photon absorption stereolithography, this leads to a microfluidic system with a built-in micromixer in a site controlled manner. The effectiveness of CMM is investigated numerically and experimentally. Through the numerical simulation, it is estimated that a high mixing ratio of 90% can be obtained even in a channel length shorter than five times the channel width. This compares well with the conventional passive type of micromixers that have a gradual increase in mixing efficiency with the length of the channel. Furthermore, the mixing performance of the realized CMM built-in microchannel is observed by confocal microscopy.

An effective splitting-and-recombination micromixer with self-rotated contact surface for wide Reynolds number range applications

“…Another method to construct pattern of the microchannel is to utilize conventional photolithography process. Examples contain micromixers fabricated with two 9 or three PDMS layers 32 or by inserting microstructures 33 in the channel. Although some of the micromixers can be short enough and effective at low Reynolds number (Re) or Peclet number (Pe), the mixing efficiency would apparently decline as Re increases.…”

In-channel integration of designable microoptical devices using flat scaffold-supported femtosecond-laser microfabrication for coupling-free optofluidic cell counting

“…Microoptical components require high surface smoothness to guarantee their optical performance compared with other microcomponents. [16][17][18][19][20]30,31 Moreover, the flatness of the internal surfaces of the microchannels on which the components are created significantly affects their quality. Over areas measuring a few dozen microns on a side, the surfaces fabricated by FLAE have adequate optical quality.…”

“…30 The fabricated microchips are called ship-in-a-bottle biochips and have been used for successive filtering, mixing and synthesizing. A number of groups have also demonstrated the integration of functional polymer microcomponents, such as 3D microporous constructs 18 and microfilters, 20 into the closed glass microfluidic channels, which are prepared by non-laser technology. Our FLAE provides the advantage over these works that an identical femtosecond laser 3D micromachining system can successively implement both FLAE (subtractive manufacturing) and TPP (additive manufacturing), leading to more cost-effective and flexible fabrication of functional biochips.…”

“…This method has been used to integrate various 3D functional microdevices, [16][17][18][19][20] such as a microfilters, 16 mixers 18 or overpasses, 19 into a 2D microchannel for controllable filtering of particles, high-efficiency mixing of different solvents, and guiding of different fluids and cell migration, respectively. However, all these works concern the integration of mechanical devices or 3D models in microchannels.…”

Progress in ultrafast laser processing and future prospects

“…The exceptional characteristics of TPP that enable 3D rapid prototyping with nanometric fabrication resolution have been extensively applied to fabricate microoptical components [64], photonic crystals [58,65,66], micro-and nanosystems [67][68][69], microfluidic devices [70][71][72], medical devices [73], and scaffold for tissue engineering [64,73,75]. Figure 10 shows examples of 3D micro-and nanostructures fabricated using TPP: (a) a 2 × 2 array of planoconvex microlens [64], (b) a photonic bandgap crystal [66], (c) a microturbine that is rotated by application of an external magnetic field [69], (d) fluid-mixing components integrated into an open microfluidic channel [72], (e) a microvalve designed to prevent reflux of blood flow in human veins [73], and (f) a 25-µm pore-sized scaffold for 3D cell migration studies [75].…”