Hydrogel-based microfluidic system for cell culture

Traditionally, cell culture has been done in culture flasks or well plates where the volumes and length scales involved in the culture environment are many orders of magnitude larger than the size scale of individual cells. To better tailor medical care to an individual patient, it may be necessary to carry out genetic, physiological, and biochemical analyses on very small cell samples and to have an in vitro cell culture environment that more closely approximates the in vivo conditions. A microfluidic device that integrates both cell handling and long-term 3-D cell culture techniques is presented. The designed microdevice traps cells with alginate, an ionically cross-linking hydrogel, which mimics the extra cellular matrix within our body. To encapsulate the cells, a solution of calcium ions is introduced in parallel with the alginate precursor cell suspension. Alginate hydrogel forms at the interface and as the region of gel grows it traps cells inside. This is a reversible process; the gel matrix can be dissolved and the cells can be released by the addition of ethylene-diaminetetraacetic acid (EDTA), a calcium chelator. To show that the microfluidic device is reliable for long term mammalian cell culture, hepatocytes and breast tumor cells were cultured within the alginate gel layer inside the microfluidic device for more than two weeks. Hepatocytes were able to form three-dimensional aggregates within the microfluidic hydrogel environment. We further demonstrate the possibility of performing anticancer agent screening within this device. Breast tumor cells seeded in the microchannel were treated with doxorubicin, a common chemotherapy drug. Compared to controls, the doxorubicin inhibited cell proliferation. In future, this system will have applications in cell-based testing and in studies involving small cell populations, such as cancer cells obtained from needle biopsies of tumors.Applied Science, Faculty ofGraduat