Difference between revisions of "Team:TU Delft"

The goal of our biological microlenses is to increase the fraction of light captured by the detector of a microscope. Lenses are known to focus light onto a surface. By applying a layer of our biological microlenses on the detector of a microscope, we can increase the fraction of light captured. To produce microlenses, we expressed the enzyme silicatein in our cells, which catalyzes polymerization of silicic acid (Cha et al., 1999). This results in a biosilica layer around the cell (Muller et al., 2008), allowing the cell to function as a microlens. Since the shape of the lenses is a crucial property, we also overexpressed the gene bolA in our silica covered cells, which produces a round cell shape when overexpressed (Aldea & Concha, 1988), to produce round lenses. Apart from using the lenses for microscopy, we can also use the lenses for improving the efficiency of solar panels, thin lightweight cameras with high resolution or 3D screens.

By turning a cell into a biolaser, we will increase the light intensity emitted by the fluorescent cell. The cell will then emit more photons without changing the fluorophore concentration. When more photons are emitted, more photons can be detected by the microscope. A laser works by resonating photons within a closed space, in this case a cell of E. coli. We approached this by expressing fluorescent proteins within our biosilica-covered cells we used for our biolenses. When exciting the fluorophores, a fraction of the photons are trapped inside the cell by the biosilica layer. When these photons meet other excited fluorescent proteins they cause them to emit a photon with the same wavelength and direction, this process is called ‘stimulated emission’ (Einstein, A. 1917) and results in light with a higher intensity and thus more emitted photons compared to conventional fluorescence.