Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture: Part 1 Design and feasibility

Abstract

Design, fabrication, integration, and feasibility test results of a novel microfluidic cell capture device is presented, exploiting the advantages of proton beam writing to make lithographic irradiations under multiple target tilting angles and UV lithography to easily reproduce large area structures. A cell capture device is demonstrated with a unique doubly tilted micropillar array design for cell manipulation in microfluidic applications. Tilting the pillars increased their functional surface, therefore, enhanced fluidic interaction when special bioaffinity coating was used, and improved fluid dynamic behavior regarding cell culture injection. The proposed microstructures were capable to support adequate distribution of body fluids, such as blood, spinal fluid, etc., between the inlet and outlet of the microfluidic sample reservoirs, offering advanced cell capture capability on the functionalized surfaces. The hydrodynamic characteristics of the microfluidic systems were tested with yeast cells (similar size as red blood cells) for efficient capture.

Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture Part 2: Image sequence analysis based evaluation and biological application

“…The calculated steady‐state streamlines, as characteristic representation of the time‐dependent solution, are shown in Fig. , while additional modeling results were discussed earlier . As one can observe, some of the streamlines end up at the pillars (especially in the lower middle section, depicted by arrows), suggesting that the fluid flow rate was below a certain specific velocity value, where most likely cell movements stopped.…”

“…) were shifted toward the inclined side of the pillars. Most likely, this displacement effect was due to the asymmetric pressure and shear force distribution near the tilted micropillars . Such a significant displacement effect proved to be especially beneficial from the capture efficiency point of view since cells, which were pushed toward the antibody covered pillar surface, were captured with higher probability.…”

“…Details of the modeling approach were previously reported . Briefly, the CAD model of the entire doubly tilted pillar array was imported in COMSOL Multiphysics (version 4.3.0.151, Stockholm, Sweden).…”

“…Design, fabrication, integration, and feasibility test results of a microfabricated cell capture device (MCCD) were published in the first part of this paper highlighting the advantages of a novel combination of proton beam writing (PBW) and conventional UV lithography. The resulting unique hybrid device had a small inner part of doubly tilted micropillar array for improved cell capture, fabricated by PBW, while the surrounding area of the chip was generated using UV lithography.…”

“…This novel combination extended the potential of conventional microstructuring techniques generating high interest both from engineering and biological application points of views. The computational fluid dynamics (CFD) assisted chip design and the entire microfabrication process was demonstrated with some preliminary test results on flow characteristics .…”