Controlled adhesion, membrane pinning and vesicle transport by Janus particles

Abstract

The interactions between biomembranes and particles are key to many applications, but the lack of controllable model systems to study them limits the progress in their research. Here, we describe...

Driven Engulfment of Janus Particles by Giant Vesicles in and out of Thermal Equilibrium

“…We have demonstrated that engulfment of Janus particles by GUVs can be driven by an external centrifugal force F C and in the absence of strong chemical or physical modifications in the system: strong membrane binding, electrostatic attraction, depletion interaction, and very low membrane tension [9][10][11]. This force F C is required to overcome an energy barrier for adhesion and engulfment, which may result from electrostatics, repulsion due to membrane fluctuations, or membrane stretching and bending [7,10,31,32].…”

“…Note that both the vesicle and the particle possess slightly negative surface potentials [18][19][20]. Hence, membrane engulfment or adhesion is not driven by charge effects [11]. For SiO 2 -Pt colloids, the rare partial engulfment observed will be discussed as a consequence of a complete membrane adhesion on the colloid's surface, which may result in a full coating of the particle by the lipids and lead to membrane rupture in the GUVs.…”

“…Only recently, Spanke et al investigated the interaction of POPC GUVs with polystyrene (PS) microparticles and observed that particle engulfment by a GUV is only possible for very low membrane tensions (<10 −8 N m −1 ) and in the presence of attractive depletion interaction, which can be tuned by adding polymers in the aqueous medium [10]. For iron oxide-PS Janus particles, Ewins et al have very recently shown that positively charged GUVs (DOPC containing a small percentage of DOTAP) are able to engulf negatively charged PS particles and PS-based Janus particles [11]. Membrane wrapping occurs for low membrane tensions, and partial engulfment of Janus particles and complete engulfment of bare PS particles can be observed.…”

Morphology of vesicle triplets: shape transformation at weak and strong adhesion limits

“…Morphological changes due to vesicle adhesion have been studied in many systems, such as vesicles adhering to other vesicles, [17][18][19] substrates, 20,21 and colloidal particles. [22][23][24][25][26] In this study, we investigate the shapes of three adhering vesicles with varying reduced volume in both strong and weak adhesion regimes. We explore two triplet topologies, the triangle and the linear one.…”

Entry of Microparticles into Giant Lipid Vesicles by Optical Tweezers

“…Dispersion of the data shown in Fig. 4B could be interpreted in terms of a distance-dependent particle-membrane adhesion w(h), which can result from the contributions of electrostatic double layer [35], steric [20], hydrophobic and Van der Waals interactions [36].…”