On the origin of spontaneous electrical oscillations in a minimal peptide assembly

The design of functional materials involves understanding how complex functionalities can emerge from simple material building blocks. In this context, peptide-based systems represent a versatile materials platform due to their chemical diversity, tunability and compatibility with sustainable processing routes. However, the conditions under which electrical functionality can emerge in minimal, abiotic peptide assemblies remain poorly understood. Here, we report the design and characterization of a minimal peptide-based material obtained through abiotic thermal polymerization, exhibiting spontaneous and persistent electrical oscillations under constant environmental conditions. The material is formed by the thermal condensation of four amino acids (Asp, Glu, Arg, Leu), resulting in a chemically heterogeneous ensemble of short oligomeric peptides. A comprehensive materials characterization combining DOSY NMR, HPLC-MS, FTIR, DLS, SEM, and qualitative Biuret assays reveals a disordered, proteinoid-like assembly with dynamic aggregation–disaggregation behaviour and strong coupling to ionic transport in the surrounding medium. Electrical measurements demonstrate autonomous oscillatory signals arising under constant environmental conditions and in the absence of external stimulation. Simultaneous dynamic light scattering and electrical measurements reveal a direct correlation between electrical oscillations and aggregation–disaggregation dynamics, indicating that the electrical activity emerges as a collective property of chemically heterogeneous peptide ensembles rather than from individual molecular species. These results provide experimentally grounded insight relevant to the design of peptide-based functional materials, highlighting minimal peptide assemblies as a promising platform for adaptive sensing, bio-inspired interfaces, and unconventional computing applications.