biostudies-literatureUnknown7(1)Miller AWe gratefully acknowledge funding from the Finlay Scholarship and the Frances and Augustus Newman Foundation.Many proteins self-assemble to form amyloid fibrils, which are highly organized structures stabilized by a characteristic cross-β network of hydrogen bonds. This process underlies a variety of human diseases and can be exploited to develop versatile functional biomaterials. Thus, protein self-assembly has been widely studied to shed light on the properties of fibrils and their intermediates. A still open question in the field concerns the microscopic processes that underlie the long-time behaviour and properties of amyloid fibrillar assemblies. Here, we use atomic force microscopy with angstrom-sensitivity to observe that amyloid fibrils undergo a maturation process, associated with an increase in both fibril length and thickness, leading to a decrease of their density, and to a change in Communications biology153https://www.ebi.ac.uk/biostudies/studies/S-EPMC10847148biostudies-literatureMaturation-dependent changes in the size, structure and seeding capacity of Aβ42 amyloid fibrils.PMC10847148Knowles TPJVendruscolo MKlimont ERuggeri FSMiller AChia SfalseMaturation-dependent changes in the size, structure and seeding capacity of Aβ42 amyloid fibrils.Many proteins self-assemble to form amyloid fibrils, which are highly organized structures stabilized by a characteristic cross-β network of hydrogen bonds. This process underlies a variety of human diseases and can be exploited to develop versatile functional biomaterials. Thus, protein self-assembly has been widely studied to shed light on the properties of fibrils and their intermediates. A still open question in the field concerns the microscopic processes that underlie the long-time behaviour and properties of amyloid fibrillar assemblies. Here, we use atomic force microscopy with angstrom-sensitivity to observe that amyloid fibrils undergo a maturation process, associated with an increase in both fibril length and thickness, leading to a decrease of their density, and to a change in 2024-01-01T00:00:00Z2024 Feb2025-04-05T00:01:46.3Z2025-04-05T00:01:46.3ZS-EPMC108471483832114410.1038/s42003-024-05858-7