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Biomolecules, such as proteins and peptides, can be self-assembled. They are widely distributed, easy to obtain, and biocompatible. However, the self-assembly of proteins and peptides has disadvantages, such as difficulty in obtaining high quantities of materials, high cost, polydispersity, and purification limitations. The difficulties in using proteins and peptides as functional materials make it more complicate to arrange assembled nanostructures at both microscopic and macroscopic scales. Amino acids, as the smallest constituent of proteins and the smallest constituent in the bottom-up approach, are the smallest building blocks that can be self-assembled. The self-assembly of single amino acids has the advantages of low synthesis cost, simple modeling, excellent biocompatibility and biodegradability in vivo. In addition, amino acids can be assembled with other components to meet multiple scientific needs. However, using these simple building blocks to design attractive materials remains a challenge due to the simplicity of the amino acids. Most of the review articles about self-assembly focus on large molecules, such as peptides and proteins. The preparation of complicated materials by self-assembly of amino acids has not yet been evaluated. Therefore, it is of great significance to systematically summarize the literature of amino acid self-assembly. This article reviews the recent advances in amino acid self-assembly regarding amino acid self-assembly, functional amino acid self-assembly, amino acid coordination self-assembly, and amino acid regulatory functional molecule self-assembly.

The self-assembly behavior of polypeptides is common in nature. Compared with monopeptides, polypeptide-based self-assembled nanomaterials with ordered structures have good thermal stability, mechanical stability, semi-conductivity, piezoelectric and optical properties. In recent years, the self-assembly of polypeptides has become a hot topic in the material science and biomedical field. By reasonably adjusting the molecular structure of the polypeptide and changing the external environment of the polypeptide, the polypeptide can be self-assembled or triggered by non-covalent bonding forces such as hydrogen bond, hydrophobicity, and π - π accumulation to form specific polypeptide assemblies such as nanoparticles, hydrogels, nanofibers, and micelles. Due to good biocompatibility and controllable degradability, polypeptide-based self-assembled nanomaterials have been widely used in the fields of nanotechnology, imaging technology, biosensor, and biomedical science. As a new drug delivery system, the polypeptide-drug conjugate has the advantages of low toxicity, high efficiency, enhanced drug stability, and avoiding side effects. This paper reviews the research progress of polypeptide-drug self-assembly nanostructure in recent years. Several structural models of polypeptide self-assembly technology and the mechanism of polypeptide self-assembly are introduced. Then the assembly form of polypeptide-drug self-assembly and the application of self-assembly compound therapy is described.