Stem cells can be induced to become tissue/organ-specific cells if subjected to proper conditions– a process known as directed differentiation. This opens up new opportunities for the treatment of diseases such as diabetes and heart disease. Differentiation can be induced through mechanical or bio-chemical stimuli. Traditionally, stem cells grow submersed in a culture medium in plastic wells that doesn’t provide means for applying specific stimuli to a target cell. Some bioreactors exist to address this, but these can’t usually vary mechanical and biochemical stimuli on the fly. And importantly, they can usually not be used to study single cells.
What it does
We invented a device that can deliver mechanical and bio-chemical stimuli, which vary over time, to individual stem cells. Different, individually addressable compartments, each containing one (or a few) cells can be arranged into an array. This makes it possible to evaluate many different combinations of time-varying stimuli in parallel.
How it works
A single-cell differentiation compartment is shown in Fig.1: The cell sits on a piezoelectric element covered by a thin, flexible plastic layer. The piezoelectric element extends when an electrical field is applied to it; since the cell is attached to the piezoelectric element, the cell will also be stretched. This setup is suspended in a cell culture fluid that contains a device for delivering biochemical stimulants on demand: a chunk of a conductive polymer which has a special structure that expands and releases biomaterial into the cell culture liquid when an electric field is applied. These two elements enable full control over the stimuli delivered to each cell (or small cluster of cells).
Figure.1: Schematic representation of a cell culture compartment. The target cell (10) is immersed into the cell culture fluid (160). The cell attaches to the piezoelectric element (120) through an extensible attachment layer (130), sitting atop a porous membrane (110).
A conductive polymer (150) releases bio material into the fluid whenever it is electrically stimulated.