A new method for fabrication of cationized ferritins on Au/Si by wet chemical etching

We have developed and studied a new fabrication method for preparation of uniform and well-organized two-dimensional arrays of cationized ferritins on gold film. These arrays were deposited on wet chemically etched Si substrates. The surface conditions of the ferritins on Au film, prepared by using a spin-self assembly method, were examined with atomic force microscopy. The results showed that the ferritin molecules were adsorbed less on Au/non-etched Si, but were adsorbed very well on Au/etched Si. These results indicate that the adhesion capability of cationized ferritin molecules strongly depends on whether the Si surface is wet-etched or not. A possible physical origin of the adsorption mechanism is that the Au/etched Si attracts cationized ferritin molecules. The negative charge of the gold surface is caused by an electrostatic force due to the dangling bonds in the interface between the Au and the Si substrate, which are generated by the etching process. This mechanism results in well-grown ferritin films.