US scientists have developed a model of the breast ductal system that could be used to discover abnormal cells or deliver drugs at locations further along the ducts than other techniques. The model fits on a slide, enabling on-chip experiments.
The human mammary gland consists of branched ducts with channels of decreasing size that are increasingly more difficult to access to obtain cell samples. This is because the channels get too narrow so the liquid inside them does not move around enough for probes to pass through to collect the cells. Now, a team led by Sophie Lelièvre and James Leary at Purdue University, Indiana, have mimicked the ductal system by making branched channels from polydimethylsiloxane (PDMS). They then moved magnetic particles along the channels through static fluid using a magnet.
The team coated the PDMS with extracellular matrix – a protein scaffold that supports cells. From this, they formed a tubular structure in which to culture mammary epithelial cells. Due to stress from the tube walls, the cells did not survive in straight tubes, so the team engineered U-shaped half channels, or hemichannels, instead. They were then able to culture cells on them, and covered the channels with a PDMS membrane to form tubes.
Schematic of the branched channel system
Link to journal articleBreast on-a-chip: mimicry of the channeling system of the breast for development of theranostics
Meggie M.G. Grafton, Lei Wang, Pierre-Alexandre Vidi, James Leary and Sophie A. Lelièvre
Integr. Biol., 2011, DOI: 10.1039/c0ib00132e