Glycosylation-mediated targeting of carriers

For safe and effective therapy, drugs should be delivered selectively to their target tissues or cells at an optimal rate. Drug delivery system technology maximizes the therapeutic efficacy and minimizes unfavorable drug actions by controlling their distribution profiles. Ligand-receptor binding is a typical example of specific recognition mechanisms in the body; therefore, ligand-modified drug carriers have been developed for active targeting based on receptor-mediated endocytosis. Among the various ligands reported thus far, sugar recognition is a promising approach for active targeting because of their high affinity and expression. Glycosylation has been applied for both macromolecular and liposomal carriers for cell-selective drug targeting. Recently, the combination of ultrasound exposure and glycosylated bubble liposomes has been developed. In this review, recent advances of glycosylation-mediated targeted drug delivery systems are discussed

Probing the mechanism of fusion in a two-dimensional computer simulation.

A two-dimensional (2D) model of lipid bilayers was developed and used to investigate a possible role of membrane lateral tension in membrane fusion. We found that an increase of lateral tension in contacting monolayers of 2D analogs of liposomes and planar membranes could cause not only hemifusion, but also complete fusion when internal pressure is introduced in the model. With a certain set of model parameters it was possible to induce hemifusion-like structural changes by a tension increase in only one of the two contacting bilayers. The effect of lysolipids was modeled as an insertion of a small number of extra molecules into the cis or trans side of the interacting bilayers at different stages of simulation. It was found that cis insertion arrests fusion and trans insertion has no inhibitory effect on fusion. The possibility of protein participation in tension-driven fusion was tested in simulation, with one of two model liposomes containing a number of structures capable of reducing the area occupied by them in the outer monolayer. It was found that condensation of these structures was sufficient to produce membrane reorganization similar to that observed in simulations with "protein-free" bilayers. These data support the hypothesis that changes in membrane lateral tension may be responsible for fusion in both model phospholipid membranes and in biological protein-mediated fusion