Maria Eleni Dimotsantou
This image includes a Si3N4 substrate functionalized with MPTMS in order to contain free sulfhydryl groups. I diluted maleimide Streptavidin, that was initially in lyophilized form containing sodium citrate, in Phosphatase Buffer Saline. The salts precipitate overnight at 4oC on the charged surface forming this fractal like pattern. The white 2 micron crystals are probably NaCl, while the smaller "tree-like" patterns are sodium citrate, KCl, Na2HPO4 • 2 H2O and KH2PO4.