Micro- and Nanocapsules Based on Artificial Peptides.

Huayang Feng

doi:10.3390/molecules27041373

Abstract

The encapsulation of active ingredients into solid capsules from biodegradable materials has received significant attention over the last decades. In this short review, we focus on the formation of micro- and nano-sized capsules and emulsions based on artificial peptides as a fully degradable material. It deals with various approaches for the preparation of peptide-based capsules as well as with their crucial properties such as size and stability. We categorize all preparation procedures into three basic approaches: self-assembly, polymerization and crosslinking, and layer-by-layer technology. This article is meant to offer a short overview over all successful methods suitable for obtaining access to these very promising carrier systems.

Highlights

IntroductionDifferent synthetic pathways tend to generate different kinds of peptides, such as oligopeptides and polypeptides
Natural peptides, which are quite abundant in nature, are composed of amino acids linked by peptide bonds
For capsules or emulsions formed only based on amphiphilic interactions, the dispersion stability can be adjusted by controlling the configuration and block ratio of the peptide

Summary

Introduction

Different synthetic pathways tend to generate different kinds of peptides, such as oligopeptides and polypeptides Various structures, such as nanotubes [4], nanofibers [5], hydrogels [6], nanovesicles [7], and nanocapsules [8], can be obtained through the self-assembly process of peptides. Considering that vesicles have analogue structures such as capsules, the related works based on self-assembly of peptides into vesicles are briefly introduced at this point, even though no hydrophobic core is involved. In 2005, Holowka et al reported the preparation of vesicles self-assembled from a series of poly(L-lysine)-b-poly(L-leucine) block copolypeptides as well as the poly(Lglutamatic acid)-b-poly(L-leucine) block copolypeptide They proved that the proper ratio of diblock peptide chain length and the stable α-helical conformations in the oligoleucine segments are essential for the formation of the vesicles [24]. Schematic illustration of biomolecule-loaded nanocapsules cross-linked by Au ion by Au ion reduction [28]. (d) Schematic illustration of the structure of (PGA/PLL-Pt(IV)) microcapreduction [29]. [28]. (d) Schematic illustration of the structure of (PGA/PLL-Pt(IV)) microcapsules [29]

Capsule Formation by Polymerization and Crosslinking

Properties of Peptide Capsules

Conclusions and Perspectives