Figure 2

The QCM device and schematics of the established and bioactive cell based biosensor. We construct QCM devices using gold coated 10 MHz crystals and biocompatible materials for the growth of cells in a cylinder chamber filled with growth media, as described in the methods. The entire QCM device containing live cells can then be capped, as shown, for employment in non-laboratory settings and air samples perfused into the device in a controlled manner for periodic environmental testing (panel A). To create the living cell biosensor, macrophages are added to the growth media above the crystal and cells sediment down to and attach to the quartz crystal surface over a 24 hr period. When SWCNTs, polystyrene beads or Zymosan A are added to the media of stably attached cells within the QCM, the cells will phagocytose this material (panel B). These behaviors will be measured by changes in the crystal oscillation frequency. For example, in the act of attachment (1) and spreading (2-4), the cells will synthesize and polymerize cytoskeletal elements (panel C). Round cells will cause a maximal decrease in crystal frequency oscillation whereas with increased spreading and distribution of cellular mass, the crystal frequency will increase from steps 1 thru 4 and reach a level of homeostasis that is cell number dependent (panel C). Without perturbation, this frequency will remain stable. However, if macrophages are then stimulated to phagocytose, they will exhibit increased migration, involving re-rounding via de-polymerizing these cytoskeletal elements then re-polymerizing these monomers into highly aligned long elements to promote hyperextension of unilateral processes (step 5, panel C).