Triblock Copolymer as an Effective Membrane-Sealing Material

Abstract

An intact cell membrane serves as a permeable barrier, regulating the influx and efflux of ions and small molecules. When the integrity of the membrane is compromised, its barrier function is also disrupted, threatening the survival of the cell. Triblock copolymer surfactants of the form poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) have been shown to help seal structurally damaged membranes, arresting the leakage of intracellular materials.In order to understand how this particular family of triblock copolymers helps seal damaged membranes, model lipid monolayer and bilayer systems have been used to unravel the nature of the lipid/copolymer interaction. The copolymer surfactant is found to selectively insert into structurally compromised membranes, thus localizing its sealing effect on the damaged regions. The inserted polymer is "squeezed out" when the lipid packing density is increased, suggesting a mechanism for the cell to be rid of the polymer when the membrane integrity is restored.

Behavior of P85 and P188 Poloxamer Molecules: Computer Simulations Using United-Atom Force-Field

“…It is known that poloxamers such as P188 have membrane-sealing properties and can be used as agents that restore the integrity of a damaged membrane. − The molecular details of how this occurs are not known, and molecular dynamics simulations could potentially provide molecular resolution pictures of the possible mechanism by which these molecules work. Recently, using coarse-grained simulations, we studied the behavior of micelles of P188 next to a damaged membrane .…”

“…During all the runs we performed we did not observe a P85 translocation to the other side of the membrane, since such a translocation would require overcoming a significant free energy barrier. 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 It is known that poloxamers such as P188 have membrane sealing properties and can be used as agents that restore the integrity of a damaged membrane [61][62][63] . The molecular details of how this occurs are not known and molecular dynamics simulations could potentially provide molecular resolution pictures of the possible mechanism by which these molecules work.…”

Properties of Poloxamer Molecules and Poloxamer Micelles Dissolved in Water and Next to Lipid Bilayers: Results from Computer Simulations

“…P188 poloxamer molecules are widely used as membrane sealants and, as observed in the experiments, they help to heal the damage caused to the membrane by closing pores in them. 4,5,9 Despite the fact that it is important to understand the molecular detailed picture of the pore closure assisted by the P188 poloxamer, experiments did not provide such a picture, and we hope that computer simulations can help in this case also. Our present simulation showed (see Figure 3) that after a 1 μs run the hydrophobic part that is the core of the P188 micelle forms a rod-like structure with length and width of ∼6 and ∼3 nm, respectively, although the overall structure of the micelle had a more spherical shape.…”

“…One can vary the PEO and PPO chain lengths and produce poloxamers with a variety of properties and functions. Because of their nontoxic nature and high solubility in water they are widely used to facilitate gene/drug delivery, as emulsifying agents, or as agents helping in healing damaged cell membranes. − …”

Janus Particles Templated from Double Emulsion Droplets Generated Using Microfluidics

“…Alternatively, droplets produced ,− , with a microfluidic device using either a coflow or a flow-focusing geometry can be polymerized using UV-radiation, heat, or chemical means to form spherical and discoidal shaped particles. ,,,,, The microfluidic techniques yield monodisperse particles whose dimensions can be precisely controlled. These techniques can also be used to make anisotropic particles, or Janus particles. − Such particles possess two sides with distinct compositions − and, depending upon their functional anisotropy, can be useful for various applications, such as emulsion stabilization − and optical probing of chemical, biological, and rheological phenomena. − The microfluidic principles for fabricating Janus particles are similar to those for fabricating homogeneous particles; however, instead of flowing one stream of monomer, two separate streams are coflowed through the same channel of the microfluidic device. To successfully fabricate Janus particles, the coflowing streams must remain parallel at all times; any perturbations can lead to cross-mixing of the fluids and to the formation of particles with a mixed internal morphology instead of particles with two distinct sides .…”