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Liposomes Entrapped in Biopolymer Hydrogels Can Spontaneously Release into the External Solution. | LitMetric

Liposomes Entrapped in Biopolymer Hydrogels Can Spontaneously Release into the External Solution.

Langmuir

Department of Chemical & Biomolecular Engineering, University of Maryland, College Park, Maryland 20742, United States.

Published: July 2020

AI Article Synopsis

  • Hydrogels made from biopolymers like agar and gelatin are utilized for various purposes, often incorporating nanoparticles like liposomes, which can slowly release encapsulated substances over time.
  • The study focuses on the creation of liposomes embedded in agar gels that can release into water over 1-3 days while the gel remains structurally intact, influenced by factors like agar concentration and temperature.
  • The research proposes a mechanism for this release, where liposomes deform and pass through temporary larger pores in the gel structure, suggesting potential applications for delivering active ingredients through the skin.

Article Abstract

Hydrogels of biopolymers such as agar and gelatin are widely used in many applications, and in many cases, the gels are loaded with nanoparticles. The polymer chains in these gels are cross-linked by physical bonds into three-dimensional networks, with the mesh size of these networks typically being 10-100 nm. One class of "soft" nanoparticles are liposomes, which have an aqueous core surrounded by a lipid bilayer. Solutes encapsulated in the liposomal core can be delivered externally over time. In this paper, we create liposomes with diameters ∼150 nm from an unsaturated phospholipid (lecithin) and embed them in agar gels (the aqueous phase also contains 0-50% of glycerol, which is an active ingredient in cosmetic products). Upon placing this gel in quiescent water, we find that the liposomes release out of the gel into the water over a period of 1-3 days, even though the gel remains intact. . We show that the release rate of liposomes can be tuned by several variables: for example, the release rate increases as the agar concentration is lowered and the rate increases steadily with temperature. In addition to agar, release of liposomes also occurs out of other physical gels including those of agarose and gelatin. However, liposomes made from a saturated phospholipid do not release out of any gels. We discuss a possible mechanism for liposomal release, which involves intact liposomes deforming and squeezing through transient large pores that arise in physical networks such as agar. Our findings have relevance to transdermal delivery: they suggest the possibility of systematically delivering liposomes loaded with actives out of an intact matrix.

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Source
http://dx.doi.org/10.1021/acs.langmuir.0c00596DOI Listing

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