Understanding poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel as a multifunctional membrane in microfluidic cell culture platform

Cell culture technology developed at the turn of 20th century using Petri dish, which is not able to consider the microenvironment that the cells experience in vessels, has remained virtually unchanged for almost a century. However, such microenvironment associated with cell culture which usually consists of soluble factors, extracellular matrix cues, and cellular networks is difficult to reproduce experimentally with the traditional approach. In order to further elaborate complex mechanisms of cell biology through mimicking such microenvironment in vivo, the technical approaches together with developed microdevices are highly demanded within such a context. Microfluidic devices have been extensively developed and used for cell culture in the last two decades, which offer numerous advantages and a great potential for accurate and efficient control of the complex culturing microenvironment at cellular length scale. However, these devices are relatively complex in their fabrication and integration to fulfil multifunctional tasks for cell culture and drug testing simultaneously, which for example requires a membrane between the culture chamber and drug delivery reservoir to control microenvironment at cellular scale. This thesis is to primarily focus on the feasibility and reliability in the attempt of using poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel as an inserted membrane, based on its permeable and flexible tissue-like properties. PHEMA membrane is able to serve dual purposes in the microfluidic systems in cell culture: i) exchanging nutrients between culture chamber and drug delivery reservoir; and ii) sealing the microchannel circuits.