UV-Induced Bursting of Cell-Sized Multicomponent Lipid Vesicles in a Photosensitive Surfactant Solution

Abstract

We study the behavior of multicomponent giant unilamellar vesicles (GUVs) in the presence of AzoTAB, a photosensitive surfactant. GUVs are made of an equimolar ratio of dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) and various amounts of cholesterol (Chol), where the lipid membrane shows a phase separation into a DPPC-rich liquid-ordered (Lo) phase and a DOPC-rich liquid-disordered (Ld) phase. We find that UV illumination at 365 nm for 1 s induces the bursting of a significant fraction of the GUV population. The percentage of UV-induced disrupted vesicles, called bursting rate (Yburst), increases with an increase in [AzoTAB] and depends on [Chol] in a non-monotonous manner. Yburst decreases when [Chol] increases from 0 to 10 mol % and then increases with a further increase in [Chol], which can be correlated with the phase composition of the membrane. We show that Yburst increases with the appearance of solid domains ([Chol] = 0) or with an increase in area fraction of Lo phase (with increasing [Chol] ≥ 10 mol %). Under our conditions (UV illumination at 365 nm for 1 s), maximal bursting efficiency (Yburst = 53%) is obtained for [AzoTAB] = 1 mM and [Chol] = 40 mol %. Finally, by restricting the illumination area, we demonstrate the first selective UV-induced bursting of individual target GUVs. These results show a new method to probe biomembrane mechanical properties using light as well as pave the way for novel strategies of light-induced drug delivery.

Nonphospholipid Fluid Liposomes with Switchable Photocontrolled Release

“…14,40 Likewise, it was reported recently that gel-phase domains or a large fraction of liquid-ordered domains were required for cis conformers to induce the bursting of Giant Unilamellar Vesicles (GUVs). 11 In the present case, the single-chain amphiphile/sterol bilayers formed display very high orientational order in the apolar core, which is a consequence of their high sterol content, 22,26 but, nevertheless, the bilayers remain fluid, as exemplified by the fast rotational motion (relative to the 2 H-NMR timescale) of the monoacylated amphiphile and of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 17 the sterol. 22,[27][28]41 The tight chain packing is probably essential for the enhancement of liposome permeability by the cis conformers reported here.…”

“…The azobenzene group is a functional group that can undergo reversible trans-cis isomerization under irradiation of UV or visible light. [9][10][11] Thermodynamically, the trans isomer is favored because of the minimized steric hindrance. Because of the greater stability of the trans form, there is thermal relaxation of the system from the cis to the trans isomer; this relaxation process is generally much slower than the photoconversion from one isomer to the other.…”

Effect of dibucaine hydrochloride on raft-like lipid domains in model membrane systems

“…[22][23][24][25][26][27] Indeed, large phase-separated liposomes have been used as models for many studies, revealing the properties of the lipid membrane. Multicomponent liposomes are known to be separated into two or three phases due to the difference in thermodynamic properties of their lipids.…”

Photo-Responsive Properties of Phospholipid Vesicles Including Azobenzene-Containing Amphiphilic Phosphates

“…The mechanism of this approach is based on the conformational changes of Az upon UV light when the Az compounds were inserted to the membrane by post-addition [20] , whose utilization efficiency of additive Az is assumed to be low.…”