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Experimental aspects of colloidal interactions in mixed systems of liposome and inorganic nanoparticle and their applications.

Michel R, Gradzielski M - Int J Mol Sci (2012)

Bottom Line: Research on these systems has led to the observation of novel hybrid structures whose morphology strongly depends on the charge, composition and size of the interacting colloidal species as well as on the nature (pH, ionic strength) of their dispersing medium.A central role is played by the phase behaviour of phospholipid bilayers which have a tremendous influence on the liposome properties.Another central aspect is the incorporation of nanoparticles into vesicles, which is intimately linked to the conditions required for transporting a nanoparticle through a membrane.

View Article: PubMed Central - PubMed

Affiliation: Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Berlin D-10623, Germany; E-Mails: raphael.michel@mailbox.tu-berlin.de (R.M.); michael.gradzielski@tu-berlin.de (M.G.); Tel.: +49-30-314-22822 (R.M.); +49-30-314-24934 (M.G.); M.G.).

ABSTRACT
In the past few years, growing attention has been devoted to the study of the interactions taking place in mixed systems of phospholipid membranes (for instance in the form of vesicles) and hard nanoparticles (NPs). In this context liposomes (vesicles) may serve as versatile carriers or as a model system for biological membranes. Research on these systems has led to the observation of novel hybrid structures whose morphology strongly depends on the charge, composition and size of the interacting colloidal species as well as on the nature (pH, ionic strength) of their dispersing medium. A central role is played by the phase behaviour of phospholipid bilayers which have a tremendous influence on the liposome properties. Another central aspect is the incorporation of nanoparticles into vesicles, which is intimately linked to the conditions required for transporting a nanoparticle through a membrane. Herein, we review recent progress made on the investigations of the interactions in liposome/nanoparticle systems focusing on the particularly interesting structures that are formed in these hybrid systems as well as their potential applications.

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Related in: MedlinePlus

Optically induced phase transition of a AuNP-modified giant unilamellar vesicle. (A)-Schematic of the phenomenon (B)-Dark-field micrograph of two adjacent gel-phase vesicles modified with gold nanoparticles. The lower vesicle illuminated with the heating laser relaxes to a spherical shape. Figure reprinted with permission from [170].
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f9-ijms-13-11610: Optically induced phase transition of a AuNP-modified giant unilamellar vesicle. (A)-Schematic of the phenomenon (B)-Dark-field micrograph of two adjacent gel-phase vesicles modified with gold nanoparticles. The lower vesicle illuminated with the heating laser relaxes to a spherical shape. Figure reprinted with permission from [170].

Mentions: Metallic nanoparticles, for instance made from gold and silver are rather frequently employed, where for Au NPs a high potential for catalytic properties exists and Ag NPs are employed in many applications due to their antimicrobial properties. Accordingly, the impact of such metal NPs on lipid bilayer presents many interesting aspects with respect to their nanotoxicity and also for further medical applications of such metal NPs. One interesting feature of metallic particles (especially Au nanoparticles) is their ability to efficiently convert electromagnetic radiation into heat. Hence, the irradiation of Au nanoparticles staying in the vicinity of a lipid membrane has been found to induce locally reversible phase transition in lipid bilayer systems by means of a laser heating. As shown in Figure 9 this phase transition can be observed optically as it may lead from facetted vesicles in the gel state to spherical vesicle in the fluid state [170]. By monitoring the size of the nanoparticles and the energy input by irradiation one can control the exact particle temperature while at the same time controlling the size of the melted footprint on the bilayer around the irradiated particle [171]. Such an optical control over the gel-fluid phase transition has also been reported to allow the guiding of a nanoparticle along the membrane plane [170]. In fact, although Au nanoparticles coated with CTAB are immobile when attached to a lipid bilayer in the gel phase, when laser heated, the particle induces the melting of the membrane in its vicinity, granting the lipids a much higher mobility thereby re-enabling its own motion. By tuning the properties of the irradiation one can achieve an effective guiding of the particle along the bilayer [170], thus enhancing the potential of single nanoparticles as thermally controlled nanotools.


Experimental aspects of colloidal interactions in mixed systems of liposome and inorganic nanoparticle and their applications.

Michel R, Gradzielski M - Int J Mol Sci (2012)

Optically induced phase transition of a AuNP-modified giant unilamellar vesicle. (A)-Schematic of the phenomenon (B)-Dark-field micrograph of two adjacent gel-phase vesicles modified with gold nanoparticles. The lower vesicle illuminated with the heating laser relaxes to a spherical shape. Figure reprinted with permission from [170].
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472766&req=5

f9-ijms-13-11610: Optically induced phase transition of a AuNP-modified giant unilamellar vesicle. (A)-Schematic of the phenomenon (B)-Dark-field micrograph of two adjacent gel-phase vesicles modified with gold nanoparticles. The lower vesicle illuminated with the heating laser relaxes to a spherical shape. Figure reprinted with permission from [170].
Mentions: Metallic nanoparticles, for instance made from gold and silver are rather frequently employed, where for Au NPs a high potential for catalytic properties exists and Ag NPs are employed in many applications due to their antimicrobial properties. Accordingly, the impact of such metal NPs on lipid bilayer presents many interesting aspects with respect to their nanotoxicity and also for further medical applications of such metal NPs. One interesting feature of metallic particles (especially Au nanoparticles) is their ability to efficiently convert electromagnetic radiation into heat. Hence, the irradiation of Au nanoparticles staying in the vicinity of a lipid membrane has been found to induce locally reversible phase transition in lipid bilayer systems by means of a laser heating. As shown in Figure 9 this phase transition can be observed optically as it may lead from facetted vesicles in the gel state to spherical vesicle in the fluid state [170]. By monitoring the size of the nanoparticles and the energy input by irradiation one can control the exact particle temperature while at the same time controlling the size of the melted footprint on the bilayer around the irradiated particle [171]. Such an optical control over the gel-fluid phase transition has also been reported to allow the guiding of a nanoparticle along the membrane plane [170]. In fact, although Au nanoparticles coated with CTAB are immobile when attached to a lipid bilayer in the gel phase, when laser heated, the particle induces the melting of the membrane in its vicinity, granting the lipids a much higher mobility thereby re-enabling its own motion. By tuning the properties of the irradiation one can achieve an effective guiding of the particle along the bilayer [170], thus enhancing the potential of single nanoparticles as thermally controlled nanotools.

Bottom Line: Research on these systems has led to the observation of novel hybrid structures whose morphology strongly depends on the charge, composition and size of the interacting colloidal species as well as on the nature (pH, ionic strength) of their dispersing medium.A central role is played by the phase behaviour of phospholipid bilayers which have a tremendous influence on the liposome properties.Another central aspect is the incorporation of nanoparticles into vesicles, which is intimately linked to the conditions required for transporting a nanoparticle through a membrane.

View Article: PubMed Central - PubMed

Affiliation: Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Berlin D-10623, Germany; E-Mails: raphael.michel@mailbox.tu-berlin.de (R.M.); michael.gradzielski@tu-berlin.de (M.G.); Tel.: +49-30-314-22822 (R.M.); +49-30-314-24934 (M.G.); M.G.).

ABSTRACT
In the past few years, growing attention has been devoted to the study of the interactions taking place in mixed systems of phospholipid membranes (for instance in the form of vesicles) and hard nanoparticles (NPs). In this context liposomes (vesicles) may serve as versatile carriers or as a model system for biological membranes. Research on these systems has led to the observation of novel hybrid structures whose morphology strongly depends on the charge, composition and size of the interacting colloidal species as well as on the nature (pH, ionic strength) of their dispersing medium. A central role is played by the phase behaviour of phospholipid bilayers which have a tremendous influence on the liposome properties. Another central aspect is the incorporation of nanoparticles into vesicles, which is intimately linked to the conditions required for transporting a nanoparticle through a membrane. Herein, we review recent progress made on the investigations of the interactions in liposome/nanoparticle systems focusing on the particularly interesting structures that are formed in these hybrid systems as well as their potential applications.

Show MeSH
Related in: MedlinePlus