SERS Investigation on Oligopeptides Used as Biomimetic Coatings for Medical Devices.

Michele Di Foggia,Santiago Sanchez-Cortes,Monica Dettin,Armida Torreggiani,Daniele Cesini,Vitaliano Tugnoli,Stefano Ottani,Annj Zamuner

doi:10.3390/biom11070959

Abstract

The surface-enhanced Raman scattering (SERS) spectra of three amphiphilic oligopeptides derived from EAK16 (AEAEAKAK)2 were examined to study systematic amino acid substitution effects on the corresponding interaction with Ag colloidal nanoparticles. Such self-assembling molecular systems, known as “molecular Lego”, are of particular interest for their uses in tissue engineering and as biomimetic coatings for medical devices because they can form insoluble macroscopic membranes under physiological conditions. Spectra were collected for both native and gamma-irradiated samples. Quantum mechanical data on two of the examined oligopeptides were also obtained to clarify the assignment of the prominent significative bands observed in the spectra. In general, the peptide–nanoparticles interaction occurs through the COO− groups, with the amide bond and the aliphatic chain close to the colloid surface. After gamma irradiation, mimicking a free oxidative radical attack, the SERS spectra of the biomaterials show that COO− groups still provide the main peptide–nanoparticle interactions. However, the spatial arrangement of the peptides is different, exhibiting a systematic decrease in the distance between aliphatic chains and colloid nanoparticles.

Highlights

In the field of functional biomaterials, peptides and oligopeptides can provide several advantages at the nanoscale, mainly related to their high biocompatibility, cell permeability, and low immunogenicity [1,2,3]
To obtain more profound insights into these factors, in the present paper, we describe a surface-enhanced Raman scattering (SERS) investigation on some oligopeptides derived from EAK16
The peptide–Ag colloid interaction is prevalent due to COO- groups, with the peptidic bond tilted and close to the silver surface even after free radical stress exposure of the biomaterials, in agreement with the quantum mechanical data indicating that the most stable optimized geometries for the analyzed peptides are obtained by silver–carboxylate interaction

Summary

Introduction

In the field of functional biomaterials, peptides and oligopeptides can provide several advantages at the nanoscale, mainly related to their high biocompatibility, cell permeability, and low immunogenicity [1,2,3]. The study of the sequences of yeasts’ proteins led to the development of synthetic materials promoting cell growth, composed of regularly alternating polar/nonpolar amphiphilic oligopeptides, whose progenitor was EAK16 (AEAEAKAK) , first synthesized by Zhang and co-workers [4,5,6] These molecular systems display complementary polar surfaces, viz. As a result, these compounds are observed to self-assemble into unusually stable β-sheet structures [4,5,7], giving rise to insoluble macroscopic membranes under physiological conditions, typically favored by monovalent cations [4]. These compounds are observed to self-assemble into unusually stable β-sheet structures [4,5,7], giving rise to insoluble macroscopic membranes under physiological conditions, typically favored by monovalent cations [4] Since their discovery, these systems have been known as “molecular Lego”. Lego bricks can be assembled only by matching specific sides, a hole-side with a peg-side, to the behavior of these peptide systems where interactions between complementary polar surfaces give rise to remarkably stable secondary structures

Methods

Results

Conclusion