Langmuir and Langmuir–Blodgett films of proline-rich N-terminal domain peptide of γ-zein

The proline-rich N-Terminal domain peptides of γ-zein (VHLPPP)n with n=1 and 3 (peptides I and II) are shown to form stable Langmuir films at air/water interface and the films have been characterized using surface pressure–molecular area (π–A), surface potential–molecular area (ΔV–A) isotherms, respectively. The longer peptide sequence does not show dramatic increase in surface or interfacial properties suggesting that the minimum length of n=1 is sufficient to achieve the necessary surface properties. Brewster angle micrographs also agreed with these results. The high surface-active nature of the peptide suggests a fairly non-polar character at air/water interface and at solid/air interface when coated expresses a high surface energy. Additives such as isopropyl alcohol (IPA) and polyvinyl alcohol (PVA) with the peptides showed more homogenous films at the air/water interface and also improved mechanical and tensile properties. The organized assembly of peptide I at the air/water and solid/air interface suggests that even thin layer of the peptide could play an important role in coating the inner surface of protein body membrane in storage proteins. Composite films of such short peptides with biocompatible polymers may find applications as surface coatings and in biomaterials.