Anosov A A, Smirnova E Yu, Korepanova E A, Kazamanov V A, Derunets A S
Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia.
Kotelnikov Institute of Radioengineering and Electronics of RAS, Moscow, Russia.
Eur Phys J E Soft Matter. 2023 Mar 15;46(3):14. doi: 10.1140/epje/s10189-023-00270-1.
The integral conductance of planar lipid bilayer membranes in the presence of two Poloxamers (Pluronics) L61 and F68 with the same lengths of hydrophobic poly(propylene oxide) blocks and the different lengths of hydrophilic poly(ethylene oxide) blocks increases with an increase in the concentration of both Pluronics; however, the shape of the conductance-concentration curves is super linear for L61 and sublinear for F68. In the presence of both Pluronics, rare discrete current jumps are observed against the background of continuous current. At high concentrations, the I-V curves of membranes with both L61 and F68 became nonlinear at sufficiently low voltages but differed significantly. At voltages greater than 50 mV, the conductance of membranes with L61 increased sharply and quantized jumps were observed toward higher conductance, which could be interpreted as the appearance of additional pores. On the contrary, the conductance of membranes with F68 decreased and quantized jumps to lower conductance were observed, which could be interpreted as blocking of already existing pores. We attributed the differences in the conductance-concentration and I-V curves of these two Pluronics to their different effects on the dynamics of membrane hydration and, accordingly, on the probability of formation of conducting pores.
在存在两种泊洛沙姆（普朗尼克）L61和F68的情况下，平面脂质双层膜的积分电导率会随着两种泊洛沙姆浓度的增加而增加。这两种泊洛沙姆具有相同长度的疏水性聚环氧丙烷嵌段和不同长度的亲水性聚环氧乙烷嵌段。然而，L61的电导率-浓度曲线形状呈超线性，而F68的则呈亚线性。在两种泊洛沙姆同时存在的情况下，在连续电流的背景下观察到罕见的离散电流跳跃。在高浓度时，含有L61和F68的膜的I-V曲线在足够低的电压下变得非线性，但差异显著。在电压大于50 mV时，含有L61的膜的电导率急剧增加，并观察到向更高电导率的量化跳跃，这可以解释为出现了额外的孔。相反，含有F68的膜的电导率降低，并观察到向更低电导率的量化跳跃，这可以解释为已存在的孔被堵塞。我们将这两种泊洛沙姆在电导率-浓度和I-V曲线上的差异归因于它们对膜水合动力学的不同影响，进而归因于形成导电孔的概率不同。
