A hydrogel-based microfluidic device for the studies of directed cell migration

Abstract

We have developed a hydrogel-based microfluidic device that is capable of generating a steady and long term linear chemical concentration gradient with no through flow in a microfluidic channel. Using this device, we successfully monitored the chemotactic responses of wildtype Escherichia coli (suspension cells) to alpha-methyl-DL-aspartate (attractant) and differentiated HL-60 cells (a human neutrophil-like cell line that is adherent) to formyl-Met-Leu-Phe (f-MLP, attractant). This device advances the current state of the art in microchemotaxis devices in that (1) it demonstrates the validity of using hydrogels as the building material for a microchemotaxis device; (2) it demonstrates the potential of the hydrogel based microfluidic device in biological experiments since most of the proteins and nutrients essential for cell survival are readily diffusible in hydrogel; (3) it is capable of applying chemical stimuli independently of mechanical stimuli; (4) it is straightforward to make, and requires very basic tools that are commonly available in biological labs. This device will also be useful in controlling the chemical and mechanical environment during the formation of tissue engineered constructs.

An agarose-based microfluidic platform with a gradient buffer for 3D chemotaxis studies

“…The device is modified from our previously reported 2D μFCD (Cheng et al 2007) and characterized in 3D. It consists of a 1.0 mm thick agarose membrane patterned with four sets of three-channel units as shown in Fig.…”

“…It is involved in a number of important processes including immune responses, tissue repair, and tumor cell metastasis, and understanding the molecular mechanisms governing directed cell migration is important for the development of new therapeutic strategies. Even though most, if not all, physiological and pathophysiological chemotaxis occurs within 3D environments, most in vitro chemotaxis experiments have been conducted in 2D settings (Abhyankar et al 2006;Boyden 1962;Frevert et al 2006;Irimia et al 2006;Irimia et al 2007;Jiang et al 2005;Li Jeon et al 2002;Shamloo et al 2008;Diao et al 2006;Cheng et al 2007;Sun et al 2008;Zigmond 1977).…”

Tuning dual-drug release from composite scaffolds for bone regeneration

“…They 35 have been studied for different medical applications, such as drug 36 delivery systems and bionanotechnology (Ankareddi and Brazel,37 2007; Gaharwar et al, 2014;Peppas et al, 2006). In particular, the 38 natural polysaccharide agarose, which is a thermo sensitive 39 hydrogel, has been successfully used in tissue engineering and 40 other biological applications (Cheng et al, 2007;Gruber et al, 41 2006; Luo and Shoichet, 2004;Marras-Marquez et al, 2014;Rotter 42 et al, 1998). Inclusion of hydroxyapatite (the mineral phase 43 present in bone) on hydrogels improves both the mechanical 44 stability and bioactivity (Juhasz et al, 2010) and also induces an 45 osteoinductive and osteoconductive behaviour.…”

A membrane-based microfluidic device for mechano-chemical cell manipulation

“…Liu et al developed a microfluidic method for monitoring in real time the effect of an anticancer drug on cancer glioma cells (Liu et al 2010). Furthermore, to generate stable chemical gradients without producing shear stress over cultured cells, gradient barriers such as membranes (Abhyankar et al 2006;Kim et al 2009) or hydrogels (Saadi et al 2007;Cheng et al 2007;Mosadegh et al 2007) have been integrated in microfluidic devices. These systems allow establishing a controllable chemical gradient without affecting the fluid flow in the cell area.…”

“…The device was validated by observing neutrophil chemotaxis in a soluble chemoattractant (IL-8) gradient. Cheng et al (Cheng et al 2007) used a hydrogel-based microfluidic device to monitor cell migration and chemotactic response of suspension cells.…”