Premium
Steep pH Gradients and Directed Colloid Transport in a Microfluidic Alkaline Hydrothermal Pore
Author(s) -
Möller Friederike M.,
Kriegel Franziska,
Kieß Michael,
Sojo Victor,
Braun Dieter
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201610781
Subject(s) - microfluidics , hydrothermal vent , colloid , chemistry , precipitation , alkaline earth metal , laminar flow , hydrothermal circulation , chemical physics , abiogenesis , microscale chemistry , chemical engineering , geology , mineralogy , nanotechnology , metal , materials science , thermodynamics , astrobiology , physics , mathematics education , mathematics , organic chemistry , meteorology , engineering
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.