Investigation of α-amylase self-assembled films on the negatively charged PET surface by AFM

It is of great interest to prepare artificial architecture of protein in thin film, which has been the focus of bioengineering in recent years. The self-assembled films of a-amylase on the negatively charged PET (PET-CO2-) is fabricated and the AFM results are described in this paper. The surface of PET-CO2- was covered by high-density layer of alpha-amylase, whose thickness was 5 - 10 nm. The molecules of alpha-amylase aggregated in the layer which was obtained from the pH 6.0 solution, and the shape of molecules became sharper, which resulted in lager RMS. On the lower-charged substrate (PET-CO2-), the aggregating molecules could be found. With raising the charge density of substrate the shape of molecules became sharper.