Steep pH Gradients and Directed Colloid Transport in a Microfluidic Alkaline Hydrothermal Pore

All life on earth depends on the generation and exploitation of ionic and pH gradients across membranes. One theory for the origin of life proposes that geological pH gradients were the prebiotic ancestors of these cellular disequilibria. With an alkaline interior and acidic exterior, alkaline vents match the topology of modern cells, but it remains unknown whether the steep pH gradients persist at the microscopic scale. Herein, we demonstrate the existence of 6 pH‐unit gradients across micrometer scales in a microfluidic vent replicate. Precipitation of metal sulfides at the interface strengthens the gradients, but even in the absence of precipitates laminar flow sustains the disequilibria. The gradients drive directed transport at the fluid interface, leading to colloid accumulation or depletion. Our results confirm that alkaline vents can provide an exploitable pH gradient, supporting their potential role at the emergence of chemiosmosis and the origin of life. Quellen des Lebens? Es wird experimentell demonstriert, dass ein pH‐Gradient von 6 pH‐Einheiten in alkalischen hydrothermalen Schloten aufrechterhalten werden kann. Die Beobachtung und Modellierung eines gerichteten Transports durch Diffusiophorese im gleichen Szenario untermauert die mögliche Rolle elektrochemischer Gradienten in alkalischen Schloten beim Entstehen von Chemiosmose und dem Ursprung des Lebens.