In the following video a magnetic microrobot is maneuvered toward a dye-laden polymer microbead. The robot and the microbead are both fluorescent, which allows quick identification of the robot as well as the bead. The first several seconds of the video are captured with epifluorescence microscopy. Toward the end of the video, the light source is switched to transmitted light microscopy. Many neuron cells are apparent slightly out of the focal plane.
In this video, a drug-laden microbead is transported and precisely positioned on a neuron dendrite. The polymer microbead gradually degrades and releases the drug over a time scale appropriate for the studies of the effect of the drug on a localized portion of the neuron cell.
Here, the frames of video are analyzed by algorithms designed to identify and track the position of the microrobot, as well as the beads. This technique may be used to automate the process of cell manipulation or drug delivery.
By specifically designing the excitation and emission wavelengths of the robot, bead and cell, it is possible to identify each object by color. In the image below, two robots emit blue light, and a polymer bead with a fluorescent dye emits orange light.