Nanocrystals

Below is an image of nanocrystals in a partially crystallized solution. The solution that these crystals are in is called MOPS buffer (morpholino-propanesulfonic acid), which is there to stabilize conditions at a constant pH. The purple circular objects are DNA nanocrystals, which are made up of DNA strands that self-assemble into triangular structures. These specific triangular DNA subunits, which can number in the hundreds, form 3D lattices, thus creating a nanocrystal. These specific nanocrystals are purple because they’ve been synthesized with ethidium bromide, a common DNA dye that is magenta in nature. In this image, the buffer has started to crystallize, forming a thin film that alters light wavelengths as they hit the crystal, resulting in a spectrum of colors. These nanocrystals are later going to be imaged using x-ray diffraction, a technique that will let us visualize exactly how the crystals are arranged on an atomic level. Having a comprehensive understanding of molecular arrangement can let scientists determine where certain molecules bind to DNA, which is important for studying the efficacy of chemotherapeutic DNA-binding drugs.