Prebiotic magnetite enables chirality-magnetic surface feedback

TL;DR

This study shows that naturally formed magnetite under prebiotic conditions can interact with chiral compounds to reinforce homochirality, potentially influencing the origin of life's molecular asymmetry.

Contribution

It demonstrates that prebiotically plausible magnetite particles exhibit magnetic properties capable of amplifying chiral bias through surface feedback mechanisms.

Findings

Magnetite synthesized via UV-driven and nitrite-mediated pathways shows distinct magnetic domain states.

Magnetic measurements confirm the presence of single-vortex and multi-vortex states in these particles.

Simulations reveal that interaction with homochiral compounds causes irreversible re-magnetization, reinforcing chiral bias.

Abstract

The emergence of biomolecular homochirality requires both an initial symmetry-breaking event and a mechanism to amplify and preserve a chiral imbalance. Magnetic minerals have been shown to function as chiral agents through the chiral-induced spin selectivity (CISS) effect and may have enabled homochirality on early Earth, yet the magnetic properties of magnetite formed under realistic prebiotic conditions remain unexplored. Here we show that magnetite synthesized through two geochemically plausible pathways - UV-driven photo-oxidation and nitrite-mediated oxidation of Fe(II) - produces particles dominated by single-vortex and multi-vortex magnetic domain states. Magnetic measurements and electron microscopy confirm that these populations differ markedly from the nano-fabricated thin-film substrates conventionally used in previous CISS experiments. Using 3D micromagnetic simulations, we demonstrate that single-domain and vortex-state grains undergo irreversible, exchange-driven re-magnetization when interacting with spin-polarized homochiral compounds. This magnetic irreversibility provides a robust mechanism for storing and reinforcing weak chiral bias, suggesting that prebiotic magnetite could have contributed to the emergence and stabilization of persistent chiral bias on the early Earth.