RESUMEN
We designed a biodegradable hybrid nanostructure for near-infrared (NIR)-induced photodynamic therapy (PDT) using an ultrasmall upconversion (UC) phosphor (ß-NaYF4:Yb3+, Er3+ nanoparticle: NPs) and a hydrocarbonized rose bengal (C18RB) dye, a hydrophobized rose bengal (RB) derivative. The UC-NPs were encapsulated along with C18RB in the hydrophobic core of the micelle composed of poly(ethylene glycol) (PEG)-block-poly(ε-caprolactone) (PCL). The UC-NPs were well shielded from the aqueous environment, owing to the encapsulation in the hydrophobic PCL core, to efficiently emit green UC luminescence by avoiding the quenching by the hydroxyl groups. The hydrophobic part of C18 of C18RB worked well to be involved in the PCL core and located RB on the surface of the PCL core, making the efficient absorption of green light and the emission of singlet oxygen to surrounding water possible. Moreover, as the location is covered by PEG, the direct contact of RB to cells is prohibited to avoid their irradiation-free toxic effect on the cells. The hybrid nanostructure proved to be degradable by the hydrolysis of PEG-b-PCL. This degradation potentially results in renal excretion by the decomposition of the nanostructure into sub-10 nm size particles and makes them viable for clinical uses. These nanostructures can potentially be used for PDT of cancer in deep tissues.
Asunto(s)
Antineoplásicos/farmacología , Materiales Biocompatibles/farmacología , Sustancias Luminiscentes/farmacología , Nanoestructuras/química , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Rosa Bengala/química , Animales , Antineoplásicos/síntesis química , Antineoplásicos/química , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/química , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Rayos Infrarrojos , Sustancias Luminiscentes/síntesis química , Sustancias Luminiscentes/química , Ensayo de Materiales , Tamaño de la Partícula , Fármacos Fotosensibilizantes/síntesis química , Fármacos Fotosensibilizantes/químicaRESUMEN
In near-infrared imaging and spectroscopy, high-fidelity modeling of photon transport for dense polydisperse colloidal suspensions is crucial. We developed photon transport models using the radiative transfer equation (RTE) with the dependent scattering theory (DST) at volume fractions up to 20%. The polydispersity and interference effects strongly influence results of the scattering properties and the RTE in cases of small mean diameter and large variance of the particle size distribution. We compared the RTE-results for the Henyey-Greenstein (conventional) function with those for the phase function using the DST. The RTE-results differ between both functions at low volume fractions for forward scattering media, suggesting the limitation of the conventional function.