Interfacial Coupling and Electrochemical Antagonism in Proteinoid-Nitella Hybrid Materials.

Abstract

Polymers predate cellular life and may have interacted with primitive cells. However, the electrical properties of such interfaces remain poorly understood. Here, we constructed and characterised a proteinoid-algal interface. Thermal proteinoids (Glu:Phe:Asp:Cys, 2:1:1:1) were synthesised at 170-200 °C. They were mixed with living internodal cells of the charophyte alga Nitella at 10:90 v/v. The system was characterised by open-circuit potentiometry for 12.1 days. Impedance spectroscopy was conducted from 0.1 Hz to 1 MHz. Cyclic voltammetry was performed over ±1.0 V. Impedance was also monitored at 1 kHz for 5.6 h. The hybrid showed distinct electrical behaviour. Its impedance was described by the same three-arc circuit used for Nitella. In contrast, the proteinoid required a finite-length Warburg element (TW = 16.1 s). The selected model for the hybrid did not require this element under the measured conditions. This is consistent with the proteinoid loading the living network rather than adding a resolvable transport pathway, but does not exclude one. Both materials showed hysteretic switching during cycling. However, only Nitella reached a stable charge ratio (Qa/Qc = 0.97 after eight cycles). The proteinoid retained an imbalanced ratio of 0.81. The living preparations also generated impulsive events and transient inductive responses. These responses cannot arise from a purely capacitive network. No inductive event was detected among 1.7 × 104 proteinoid measurements. The abiotic polymer therefore acted neither as an inert coating nor as an equivalent electrical component. Instead, it imposed an additional load on the living system.

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