Single cell trapping in larger microwells capable of supporting cell spreading and proliferation

Abstract

Conventional cell trapping methods using microwells with small dimensions (10-20 μm) are useful for examining the instantaneous cell response to reagents; however, such wells have insufficient space for longer duration screening tests that require observation of cell attachment and division. Here we describe a flow method that enables single cell trapping in microwells with dimensions of 50 μm, a size sufficient to allow attachment and division of captured cells. Among various geometries tested, triangular microwells were found to be most efficient for single cell trapping while providing ample space for cells to grow and spread. An important trapping mechanism is the formation of fluid streamlines inside, rather than over, the microwells. A strong flow recirculation occurs in the triangular microwell so that it efficiently catches cells. Once a cell is captured, the cell presence in the microwell changes the flow pattern, thereby preventing trapping of other cells. About 62% of microwells were filled with single cells after a 20 min loading procedure. Human prostate cancer cells (PC3) were used for validation of our system.

Cascade and staggered dielectrophoretic cell sorters

“…However, by its nature, this DEP sorter has a limited capability to achieve a high purity of target cells with only one sorter. Furthermore, like all other microfluidics-based cell sorters [25,28,40,41], the microfluidic DEP sorter handles normally only small volume of sample because of the small size of the microchannel, and the enrichment factor decreases with the increased throughput (i.e. flow rate Q).…”

Microparticle image velocimetry (μPIV) study of microcavity flow at low Reynolds number

“…The demand for fine and precise control of microscale fluid flows in microfluidic devices for different applications, such as cell and particle trapping Park et al 2010;Mach et al 2011), sorting (Park et al 2009;Mu et al 2013), alignment (Nilsson et al 2009;Fan et al 2014), and separating target cells from heterogeneous cell solution (Yun et al 2013;Sackmann et al 2014;Zhou et al 2013), has become a central research theme in microfluidic systems (Fishler et al 2013;Yu et al 2005). Moreover, well-defined ideal chemical microenvironments and controlled stable spatiotemporal chemical and thermal gradients in microfluidic devices are needed for better understanding of different fundamental processes involved in cell regulating mechanisms and molecular interactions (Nilsson et al 2009;Yew et al 2013).…”

“…Although much research work has been devoted to exploit the microcavities in microfluidic devices for different applications, there is still a lack of guidelines available for design or optimizing the microcavity configurations according to specific applications (Hur et al 2010Jang et al 2011;Luo et al 2007;Mach et al 2011;Park et al 2010;Zhou et al 2013). In order to reduce design ambiguity and successfully design a microfluidic device, it is necessary to thoroughly characterize the flow behaviors in the microcavities beforehand (Fishler et al 2013;Karimi et al 2013;Yew et al 2013;Yu et al 2005).…”

“…Microcavity flow has been increasingly used in microfluidic devices, and various microcavity geometric configurations have been developed for cell trapping and culture, e.g., microwells (Cioffi et al 2010;Hur et al 2010;Jang et al 2011;Luo et al 2007;Manbachi et al 2008) and microgrooves (Khabiry et al 2009;Park et al 2010) located on the bottom of the microchannel for cell docking, microcavities located on the side wall of the microchannel with square (Yu et al 2005), rectangular (Yew et al 2013), cylindrical (Fishler et al 2013), diamond and trapezoidal (Chiu 2007;Shelby et al 2003) shapes, and sharp corner structures (Fan et al 2014). Besides, rectangular microcavities have also been used for cell and particle high-throughput sorting in microfluidic devices Mach et al 2011;Park et al 2009;Zhou et al 2013).…”

Diamagnetically trapped arrays of living cells above micromagnets

“…10 More recently, large enough wells have been manufactured for the proliferation of cells in a microfluidic environment. 11 However, the direct contact of non-adherent cells such as lymphocytes with surfaces is suspected to modify the behaviour of the cells. 12,13 In the arraying process of cells in suspension, the difficulty to control the spatial distribution of cells without tethering 9 is a technology issue which needs to be tackled.…”