Photodynamic Therapy: One Step Ahead with Self-Assembled Nanoparticles

Avci, Pinar; Erdem, S. Sibel; Hamblin, Michael R.

doi:10.1166/jbn.2014.1953

Cited by 74 publications

(48 citation statements)

References 120 publications

(174 reference statements)

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“…Liposomes, micelles, nanoemulsions can all be constructed out of lipids or amphiphilic polymers that self-assemble into delivery vehicles for PSs [90]. These nanovehicles have many advantages, the most important of which are providing a big increase in photochemical efficiency, and the ability to localize in tumours after IV injection due to the EPR effect [91]. …”

Section: Nanotechnologymentioning

confidence: 99%

New photosensitizers for photodynamic therapy

Abrahamse

Hamblin

2016

Biochemical Journal

1,669

1,172

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Photodynamic therapy (PDT) was discovered more than 100 years ago, and has since become a well-studied therapy for cancer and various non-malignant diseases including infections. PDT uses photosensitizers (PSs, non-toxic dyes) that are activated by absorption of visible light to initially form the excited singlet state, followed by transition to the long-lived excited triplet state. This triplet state can undergo photochemical reactions in the presence of oxygen to form reactive oxygen species (including singlet oxygen) that can destroy cancer cells, pathogenic microbes and unwanted tissue. The dual-specificity of PDT relies on accumulation of the PS in diseased tissue and also on localized light delivery. Tetrapyrrole structures such as porphyrins, chlorins, bacteriochlorins and phthalocyanines with appropriate functionalization have been widely investigated in PDT, and several compounds have received clinical approval. Other molecular structures including the synthetic dyes classes as phenothiazinium, squaraine and BODIPY (boron-dipyrromethene), transition metal complexes, and natural products such as hypericin, riboflavin and curcumin have been investigated. Targeted PDT uses PSs conjugated to antibodies, peptides, proteins and other ligands with specific cellular receptors. Nanotechnology has made a significant contribution to PDT, giving rise to approaches such as nanoparticle delivery, fullerene-based PSs, titania photocatalysis, and the use of upconverting nanoparticles to increase light penetration into tissue. Future directions include photochemical internalization, genetically encoded protein PSs, theranostics, two-photon absorption PDT, and sonodynamic therapy using ultrasound.

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Section: Nanotechnologymentioning

confidence: 99%

New photosensitizers for photodynamic therapy

Abrahamse

Hamblin

2016

Biochemical Journal

1,669

1,172

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“…By far the best way to deliver the PS to cancers is to inject the compounds intravenously. For water-insoluble compounds, this route is likely to require a delivery vehicle such as liposomes or micelles [47]. However, for infections, the best way to deliver the PS is locally, either by topical application or by instillation.…”

Section: Light Sources Optics and Dosimetrymentioning

confidence: 99%

Advances in antimicrobial photodynamic inactivation at the nanoscale

2017

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The alarming worldwide increase in antibiotic resistance amongst microbial pathogens necessitates a search for new antimicrobial techniques, which will not be affected by, or indeed cause resistance themselves. Light-mediated photoinactivation is one such technique that takes advantage of the whole spectrum of light to destroy a broad spectrum of pathogens. Many of these photoinactivation techniques rely on the participation of a diverse range of nanoparticles and nanostructures that have dimensions very similar to the wavelength of light. Photodynamic inactivation relies on the photochemical production of singlet oxygen from photosensitizing dyes (type II pathway) that can benefit remarkably from formulation in nanoparticle-based drug delivery vehicles. Fullerenes are a closed-cage carbon allotrope nanoparticle with a high absorption coefficient and triplet yield. Their photochemistry is highly dependent on microenvironment, and can be type II in organic solvents and type I (hydroxyl radicals) in a biological milieu. Titanium dioxide nanoparticles act as a large band-gap semiconductor that can carry out photo-induced electron transfer under ultraviolet A light and can also produce reactive oxygen species that kill microbial cells. We discuss some recent studies in which quite remarkable potentiation of microbial killing (up to six logs) can be obtained by the addition of simple inorganic salts such as the non-toxic sodium/potassium iodide, bromide, nitrite, and even the toxic sodium azide. Interesting mechanistic insights were obtained to explain this increased killing.

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“…For example., photodynamic therapy [135][136][137][138][139][140] is widely studied and used for treatment of especially skin cancer and consists in an application of photosensitizer followed by laser irradiation of tumor lesion. Another potential medical application may be laser-triggered drug release from photoresponsive delivery system in the target tissue.…”

Section: Photoresponsive Systemsmentioning

confidence: 99%

“…As regards polymers, due to these disadvantages of light-responsive systems, currently only polymeric carriers of photosenzitizers for photodynamic therapy approached medical use [135][136][137][138][139][140].…”

Section: Photoresponsive Systemsmentioning

confidence: 99%