A company that grows cell cultures for tissue engineering and drug-discovery applications found that a three-axis mill on a desktop gantry could efficiently produce needed shapes and details in several materials that encourage cell growth. 3D Biotek LLC COO Wing Lau says the Gantry System LCT from Techno Inc., New Hyde Park, NY (technocnc.com) comes with closed-loop servo drives that provide an accuracy of ± 100 µm/300 mm of travel, and a repeatability of ±100 µm.

Conventional 2D cell cultures are usually grown on culture plates or 96-well plates. But cells grow in three dimensions, so 3D cell cultures provide a better model for studying interactions between cells and growth factors or therapeutic agents. What's more, most porous scaffolds are not transparent and the cells growing within them can not be directly observed or imaged using a conventional inverted microscope.

Polystyrene, one material Lau easily machines, is a noncytotoxic and transparent polymer used to fabricate many cell culture vessels. The material's transparency is a big plus compared to other porous scaffolds because it lets researchers directly observe the cell growth with microscopes.

A goal of the North Brunswick, N.J. based company (3dbiotek.com) was to develop a porous matrix that could be used to grow 3D cultures. The company's 3D Insert scaffold matrix can also be made of biodegradable polymers such as polycaprolactone (PCL) and nondegradable polymers such as polystyrene (PS).

The critical dimension in the scaffold is pore size, which ranges from 200 to 500 microns. Pores are the tiny gaps in the scaffold that cells find amenable to growth. Over a distance of 500 microns, the accuracy of the gantry is less than 1 µm so the machine can hold pore size to tighter tolerance than required. The gantry also provides a speed of 152 mm/sec, fast enough for high production rates.

After getting the gantry in house, Lau's team developed a fabrication program so a user need only type in basic scaffold parameters such as the outer dimensions and pore size. The program generates G-code toolpaths that guides the machine through an intricate series of motions required to produce needed scaffold.