Polypeptides and proteins have a high density of chemical functionality, which can be used to construct defined macromolecular nano architectures, such as low dimensional assemblies (i.e., nanoparticles, nanofibers and nanotubes), two-dimensional nanosheets, and extended three-dimensional structures (i.e., crystalline solids). Two-dimensional nanosheets are a fundamentally important geometry that bridges the gap between low dimensional assemblies and three-dimensional structures. In view of the considerable impact on a great many fundamental and applied aspects of biological and material sciences, it is therefore significant and valuable to review the recent works related to this field. In recent years, a central goal is to design novel materials with molecular-level information that can be utilized to direct highly specific intra-and intermolecular interactions promoting self-assembly of thermodynamically stable and structurally defined two-dimensional (2D) assemblies. In this review, we present a variety of strategies for constructing the 2D nano-scale assemblies and nanomaterials using specific interactions of polypeptides or similar peptoid molecules in a well-predictable manner. These controllable 2D nano materials can also display a variety of functionalities. Initially, the primary and secondary structure of peptides will be introduced. Examples of controlled fabrication of two-dimensional assemblies on the nanoscale are subsequently presented based on different secondary structures of the peptides, e.g. twodimensional crystals from a-helix, nanoscale sheets from self-assembly of collagen-mimetic peptides with triple helix, co-assembled nanosheet structures assembled from peptide-organic molecules with beta-strand conformation, and 2D crystals assembled from peptoid with Sigma-strand structure. Furthermore, macrofilms assembled from protein fibril arrays are introduced. These bottom-up strategies can arrange polypeptides and proteins into well-ordered 2D structures, which can have wide-ranging applications, such as membrane-based separations with specific mechanical properties, the control of surface properties in nanodevice and nanosensor fabrication, retroviral transduction in biology and diagnosis of some disease in biomedicine. (C) 2018 Published by Elsevier Ltd.