Novel Nanostructural Hybride Materials for Photodynamic Theraphy

Nowakowska, Maria; Nawalany, Kinga; Kępczyński, Mariusz; Krawczyk, Z

doi:10.1002/masy.200950520

Cited by 6 publications

(3 citation statements)

References 8 publications

(4 reference statements)

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“…As such, the assumption that PEG is found entirely outside the membrane, common to both assumptions of the theoretical models, and the interpretations of the experimental results − may not necessarily be valid. In addition, Nowakowska et al have obtained experimental results that suggest that PEG penetrates the interior of lipid membranes.…”

Section: Introductionmentioning

confidence: 99%

Study of PEGylated Lipid Layers as a Model for PEGylated Liposome Surfaces: Molecular Dynamics Simulation and Langmuir Monolayer Studies

Stȩpniewski

Pasenkiewicz-Gierula

Róg³

et al. 2011

Langmuir

100

120

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We have combined Langmuir monolayer film experiments and all-atom molecular dynamics (MD) simulation of a bilayer to study the surface structure of a PEGylated liposome and its interaction with the ionic environment present under physiological conditions. Lipids that form both gel and liquid-crystalline membranes have been used in our study. By varying the salt concentration in the Langmuir film experiment and including salt at the physiological level in the simulation, we have studied the effect of salt ions present in the blood plasma on the structure of the poly(ethylene glycol) (PEG) layer. We have also studied the interaction between the PEG layer and the lipid bilayer in both the liquid-crystalline and gel states. The MD simulation shows two clear results: (a) The Na(+) ions form close interactions with the PEG oxygens, with the PEG chains forming loops around them and (b) PEG penetrates the lipid core of the membrane for the case of a liquid-crystalline membrane but is excluded from the tighter structure of the gel membrane. The Langmuir monolayer results indicate that the salt concentration affects the PEGylated lipid system, and these results can be interpreted in a fashion that is in agreement with the results of our MD simulation. We conclude that the currently accepted picture of the PEG surface layer acting as a generic neutral hydrophilic polymer entirely outside the membrane, with its effect explained through steric interactions, is not sufficient. The phenomena we have observed may affect both the interaction between the liposome and bloodstream proteins and the liquid-crystalline-gel transition and is thus relevant to nanotechnological drug delivery device design.

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Section: Introductionmentioning

confidence: 99%

Study of PEGylated Lipid Layers as a Model for PEGylated Liposome Surfaces: Molecular Dynamics Simulation and Langmuir Monolayer Studies

Stȩpniewski

Pasenkiewicz-Gierula

Róg³

et al. 2011

Langmuir

100

120

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“…With increasing pH, the carboxylic groups become ionized and the chain expands due to the repulsion of the charged species along the chain. Tetraarylporphyrin (TArP) with covalently attached PMA chain was prepared and studied [26,44]. Poly(methacrylic acid)-5-(4-acryloyloxyphenyl) 10,15,20-tritolylporphyrin (PMA-Po) with no more than one porphyrin chromophore at the end of the polymeric chain was synthesized by anionic polymerization.…”

Section: Covalent Attachment Of Polymermentioning

confidence: 99%

“…(2), the PSs are large hydrophobic molecules, which results in their low solubility in aqueous environments, such as cytosol, and in augmented aggregation phenomena. It is well known that the aggregates of PS are inactive in the generation of cytotoxic reactive oxygen species [26]. The aggregation process can be described by a simple model of the monomer (M) -dimer (D) equilibrium, as follows 2 M D;…”

Section: Introductionmentioning

confidence: 99%

Nanostructural Hybrid Sensitizers for Photodynamic Therapy

Kępczyński

Dzieciuch²,

Nowakowska³

2012

CPD

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Photodynamic therapy (PDT) is a clinically approved method for treatment of cancer, microbial infections, and some other diseases. PDT has proved effective in the treatment of malignancies of various organs, including lung, bladder, gastrointestinal tract, and skin, and in the therapy of bacterial infection of skin wounds and carious lesions. It employs a combination of light and a drug (photosensitizer, PS) to induce phototoxicity against cancerous cells or bacteria. The efficiency of currently used PSs is limited due to their hydrophobic nature, which causes aggregation of the PS in aqueous media and low tumor selectivity (a low value of the tumor-to-normal tissue ratio). The purpose of this review is to present some aspects of the current state of knowledge on nanostructural carriers for the PS delivery. In this paper we reviewed studies on the development of nanostructural materials for PDT, especially those based on the polymeric and liposomal formulation of PS. We focused mainly on the nanostructural PSs obtained by the covalent attachment of hydrophilic polymer chain to the low-molecular-weight PS, the incorporation of PS into polymeric nanostructures such as micelles, and the solubilization of PS in liposome carriers.

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