Figure 2

Schematic diagram of a fiber-optical probe made by binding two parallel optical fibers together for detecting the optical changes of overlapping area of cortical neurons. (a) (upper part) The half-angle of light cone of a fiber is characterized by the numerical aperture (N.A.). With the half-angle and source/detector distance determined, the minimum distance from probe tip to dish that makes two light cones overlapping can be observed as the detection area. (b) The system setup is designed for manipulating the fiber-optical probe at varied distances from the probe tip to the culturing cells as well as for cellular experiment under varied osmotic pressures. The scattering photons are captured by PMT which can be correlated with the cell coverage of the cellular image capturing by CCD (shown at left lower corner) for calibration curve. (c) Expanded view and labeling of overlapping area for calculating the optical detection region.