Research on the supramolecular buildup of eumelanin has gained high momentum in the last years. Several new aspects regarding the involved structures and mechanisms have been established, which has led to a better understanding of the entire process. This review intends to provide a clearly laid-out summary of previous and new findings regarding structures, mechanisms, and controllability. With respect to materials applications, the aspect of controllability is of supreme importance. A focus of this review is therefore set on a novel method with high potential for specific synthesis of various, isolated particle morphologies. Finally, open questions and possibilities for their elucidation are discussed.

The natural blood protein fibrinogen is a highly potent precursor for the production of various biomaterials due to its supreme biocompatibility and cell interaction. To gain actual materials from fibrinogen, the protein needs to undergo fibrillogenesis, which is mostly triggered via enzymatic processing to fibrin, electrospinning, or drying processes. All of those techniques, however, strongly limit the available structures or the applicability of the material. To overcome the current issues of fibrin(ogen) as material, we herein present a highly feasible, quick, and inexpensive technique for self-assembly of fibrinogen in solution into defined, nanofibrous three-dimensional (3D) patterns. Upon interaction with specific anions in controlled environments, stable and flexible hydrogel-like structures are formed without any further processing. Moreover, the material can be converted into highly porous and elastic aerogels by lyophilization. Both of these material classes have never been described before from native fibrinogen. The observed phenomenon also represents the first enzyme-free process of fibrillogenesis from fibrinogen with significant yield in solution. The produced hydrogels and aerogels were investigated via electron microscopy, IR spectroscopy, and fluorescence spectroscopy, which also confirms the native state of the protein. Additionally, their mechanical properties were compared with actual fibrin and unstructured fibrinogen. The structural features show a striking analogy to actual fibrin, both as hydro- and aerogel. This renders the new material a highly promising alternative for fibrin in biomaterial applications. A much faster initiation of fiber formation, exclusion of possible thrombin residuals, and low-cost reagents are great advantages.

This article provides a comprehensive overview of the current scientific status of monomer and polymer synthesis, as well as the areas of application for (meth)acrylates based on monoterpenes, using the industrially available IBOMA as an example.