Nano particle tracking
The overall aim with the nano–related research is to be able to track individual animals, as well as their food, in their natural environment. In order to reach this aim we will initially work at laboratory scale and then, as the methodological developments proceed, expand to natural systems.
Nanoparticles are firmly attached to the Daphnias
These fluorescent probes have a strong stability, fluorescence and tunable wavelength. By changing the size of their core material they emit light at different wavelengths. Choosing from a variety of quantum dots (QD), and conjugating them with a protein called streptavidin (SA), it is possible to form a high affinity bond between the QD-SA conjugate and biotin labeled animals (as Daphnias). One can then track individual animals by labeling them with different QDs. After only a few days the Daphnia will molt and thus loose their fluorescence.
The set up
The setup The setup (A) Picture of the stereo vision system, composed by two cameras (Cam1 and Cam2) that overlook the entire aquarium from different angles. (B) Air-cooled blue-light lamp used to excite the red and yellow fluorescent nanoparticles. (C) Schematic top view of the system with cameras positioned 90° from each other.
Movements of Daphnias
After processing in ImageJ the animals movements are tracked in Matlab as in the example shown here. These individuals were recorded using two different QDs. One emitting in red (655 nm), and one in yellow (575 nm).