Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Institute of Materials Science (IMX), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Nano Lett. 2023 Nov 8;23(21):9858-9864. doi: 10.1021/acs.nanolett.3c02653. Epub 2023 Oct 23.
The unique properties of water are critical for life. Water molecules have been reported to hydrate cations and anions asymmetrically in bulk water, being a key element in the balance of biochemical interactions. We show here that this behavior extends to charged lipid nanoscale interfaces. Charge hydration asymmetry was investigated by using nonlinear light scattering methods on lipid nanodroplets and liposomes. Nanodroplets covered with negatively charged lipids induce strong water ordering, while droplets covered with positively charged lipids induce negligible water ordering. Surprisingly, this charge-induced hydration asymmetry is reversed around liposomes. This opposite behavior in charge hydration asymmetry is caused by a delicate balance of electrostatic and hydrogen-bonding interactions. These findings highlight the importance of not only the charge state but also the specific distribution of neutral and charged lipids in cellular membranes.
水的独特性质对生命至关重要。据报道，水分子在大量水中不对称地水合阳离子和阴离子，是生化相互作用平衡的关键因素。我们在这里表明，这种行为扩展到带电荷的脂质纳米级界面。通过在脂质纳米液滴和脂质体上使用非线性光散射方法研究了电荷水合不对称性。带负电荷的脂质覆盖的纳米液滴诱导强烈的水有序化，而带正电荷的脂质覆盖的纳米液滴诱导可忽略不计的水有序化。令人惊讶的是，这种带电荷诱导的水合不对称性在脂质体周围发生反转。这种电荷水合不对称性的相反行为是由静电和氢键相互作用的微妙平衡引起的。这些发现强调了不仅是电荷状态，而且细胞中中性和带电荷脂质的特定分布在细胞膜中也很重要。
