Paper
10 February 2011 MS2 bacteriophage as a delivery vessel of porphyrins for photodynamic therapy
Brian A. Cohen, Alain E. Kaloyeros, Magnus Bergkvist
Author Affiliations +
Abstract
Challenges associated with photodynamic therapy (PDT) include the packaging and site-specific delivery of therapeutic agents to the tissue of interest. Nanoscale encapsulation of PDT agents inside targeted virus capsids is a novel concept for packaging and site-specific targeting. The icosahedral MS2 bacteriophage is one potential candidate for such a packaging-system. MS2 has a porous capsid with an exterior diameter of ~28 nm where the pores allow small molecules access to the capsid interior. Furthermore, MS2 presents suitable residues on the exterior capsid for conjugation of targeting ligands. Initial work by the present investigators has successfully demonstrated RNA-based self-packaging of a heterocyclic PDT agent (meso-tetrakis(para-N-trimethylanilinium)porphine, TMAP) into the MS2 capsid. Packaging photoactive compounds in confined spaces could result in energy transfer between the molecules upon photoactivation, which could in turn reduce the production of radical oxygen species (ROS). ROS are key components in photodynamic therapy, and a reduced production could negatively impact the efficacy of PDT treatment. Here, findings are presented from an investigation of ROS generation of TMAP encapsulated within the MS2 capsid compared to free TMAP in solution. Monitoring of ROS production upon photoactivation via a specific singlet oxygen assay revealed the impact on ROS generation between packaged porphyrins as compared to free porphyrin in an aqueous solution. Follow on work will study the ability of MS2-packaged porphyrins to generate ROS in vitro and subsequent cytotoxic effects on cells in culture.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Brian A. Cohen, Alain E. Kaloyeros, and Magnus Bergkvist "MS2 bacteriophage as a delivery vessel of porphyrins for photodynamic therapy", Proc. SPIE 7886, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XX, 788614 (10 February 2011); https://doi.org/10.1117/12.875202
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Cited by 2 scholarly publications.
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KEYWORDS
Oxygen

Photodynamic therapy

Molecules

Absorbance

Proteins

Transmission electron microscopy

Packaging

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