Systems Biophysics, Physics Department, Nanosystems Initiative Munich and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799, München, Germany.
Angew Chem Int Ed Engl. 2017 Feb 20;56(9):2340-2344. doi: 10.1002/anie.201610781. Epub 2017 Jan 24.
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.
地球上所有的生命都依赖于离子和 pH 值梯度在膜间的产生和利用。生命起源的一种理论认为，地质 pH 值梯度是这些细胞失衡的前生物祖先。碱性喷口具有内部碱性和外部酸性，与现代细胞的拓扑结构相匹配，但微观尺度上陡峭的 pH 值梯度是否持续存在仍不清楚。本文中，我们在微流控喷口复制品中证明了在微米尺度上存在 6 个 pH 单位的梯度。界面处金属硫化物的沉淀增强了梯度，但即使没有沉淀，层流也能维持失衡状态。梯度在流体界面处驱动定向传输，导致胶体的积累或耗尽。我们的结果证实，碱性喷口可以提供可利用的 pH 值梯度，支持它们在化学渗透和生命起源中的潜在作用。
