Glow Discharge Plasma-assisted Self-assembly Of Peptides And Preparation Of Noble Metal-peptide Composite Material

Peptides possess specific structure, biological compatibility and biodegradability.Their self-assembly structures have been widely applied in biomedicine, clinicalmedicine and other fields. And there have many charged groups on side-chain ofpeptide molecules. They can adsorb inorganic metal ions via electrostatic or othereffects?That can self-assemble into composite with optical, electrical and catalyticfunctions, which have promising applications in optical, biological and sensing areas.At present, research focused on the traditional influencing factors such as structure,pH, concentration, temperature on the polypeptide self-assembly. However, there arefew studies of impact of hydrated electron. Hydrated electrons as chemical andbiological active species, is very important. This paper attempts to use glow dischargeplasma as a source of hydrated electrons for the study of the discharge effects onself-assembly of peptides, and try to utilize glow discharge plasma to assist thepreparation of inorganic metal-peptide complex materials.Firstly, we investigated the self-assembly behavior of peptides FF and KLVFF(A?_16-20) under the glow discharge plasma. Characterization of the polypeptideobtained by the analysis show that the peptides FF and A?_16-20solution underconventional conditions are formed into the nano-fiber structure, while after the glowdischarge plasma treatment the peptide FF self-assemble into aggregation with size ofa dozen nanometers. A?_16-20peptide self-assemble into ?-sheet rich nanofibrils andthen the fibrils packed together along the direction perpendicular to the long axis ofthe fibrils, leading to the formation of film. The thickness of the film-like aggregatesis approximately0.7nm. The speed of dynamics process for self-assembly underglow discharge plasma is faster than conventional process.Then we introduce the precious metal ions into the peptide system to research thepreparation of noble metal-peptide complex materials. The results showed that thepeptides and HAuCl₄(or H₂PtC_l6, PdC_l2) hybrid solution can form Au ?or Pt, Pd? andpeptide composite membrane structure after treatment of glow discharge plasma.During the treatment of glow discharge plasma, peptide self-assembling into film andthe noble metal ions can be reduced to nanoparticles with uniform size and combinedwith the peptide by embedded in the peptide film. The composite film is thin anduniform. The size of Au nanoparticles are mainly depend on the initial concentrationof Au³⁺. Finally, we suggest a viable self-assembly mechanism by experiments anddensity functional theory calculated. During the process of peptide self-assembly, thehydrated electron is added to form N-?hydrated electron?-N mode that enhances thebinding interaction between the peptides and therefore more conducive to fibrilspacked together along the direction perpendicular to the long axis of the fibrils whichlead to the formation of film. After the introduction of the noble metal ions, theself-assembly of peptide into film and the reduction of noble metal ions to metalnano-particles are occur simultaneously. The gold nanoparticles can be uniformlydistributed on the peptide film, leading to the assembly of noble metal-peptidecomplex film.