RESUMEN
Kinetics, biodistribution, and histological studies were performed to evaluate the particle-size effects on the distribution of 15 nm and 50 nm PEG-coated colloidal gold (CG) particles and 160 nm silica/gold nanoshells (NSs) in rats and rabbits. The above nanoparticles (NPs) were used as a model because of their importance for current biomedical applications such as photothermal therapy, optical coherence tomography, and resonance-scattering imaging. The dynamics of NPs circulation in vivo was evaluated after intravenous administration of 15 nm CG NPs to rabbit, and the maximal concentrations of gold were observed 15-30 min after injection. Rats were injected in the tail vein with PEG-coated NPs (about 0.3 mg Au/kg rats). 24 h after injection, the accumulation of gold in different organs and blood was determined by atomic absorption spectroscopy. In accordance with the published reports, we observed 15 nm particles in all organs with rather smooth distribution over liver, spleen and blood. By contrast, the larger NSs were accumulated mainly in the liver and spleen. For rabbits, the biodistribution was similar (72 h after intravenous injection). We report also preliminary data on the light microscopy and TEM histological examination that allows evaluation of the changes in biotissues after gold NPs treatment.
Asunto(s)
Oro/farmacología , Oro/farmacocinética , Nanopartículas del Metal/administración & dosificación , Animales , Coloides , Medios de Contraste/química , Medios de Contraste/farmacocinética , Medios de Contraste/farmacología , Oro/sangre , Oro/química , Histología , Inyecciones Intravenosas , Microscopía Electrónica de Transmisión , Fenómenos Ópticos , Tamaño de los Órganos/efectos de los fármacos , Tamaño de la Partícula , Polietilenglicoles/química , Conejos , Ratas , Dióxido de Silicio/química , Distribución TisularRESUMEN
The photodynamic therapy technique involving pulsed oxygen depletion (POD) in tissue by long high-energy pulses of light was studied theoretically. The possibility of creating a uniform distribution of a therapeutic dose throughout a tumor using both surface and interstitial irradiation is shown. Possible thickness of the treated tissue layer is estimated. The comparison with other methods of nonlinear photodynamic therapy is made.
Asunto(s)
Modelos Teóricos , Oxígeno/metabolismo , Fotoquimioterapia/métodos , Simulación por Computador , Relación Dosis-Respuesta en la Radiación , Luz , Oxígeno/química , Consumo de Oxígeno/efectos de la radiación , FotoquímicaRESUMEN
The photodynamic therapy involving saturation of triplet state of a photosensitizer by short high-energy light pulses was studied theoretically. The possibility of creating a uniform therapeutic dose distribution throughout a large tumor using both surface and interstitial irradiation is shown. Possible thickness of the treated tissue layer and the required duration of the PDT session are estimated.
Asunto(s)
Neoplasias/tratamiento farmacológico , Fotoquimioterapia , Fármacos Fotosensibilizantes/química , Cinética , Modelos Teóricos , Dosificación Radioterapéutica , Distribución TisularRESUMEN
Photodynamic therapy with total photobleaching of a photosensitizer was studied theoretically. The possibilities of having constant therapeutic dose within a large extent of a tissue and even of obtaining the maximal dose at a particular depth were considered. The use of both surface irradiation or interstitial irradiation were evaluated.