RESUMEN
The influence of dispersed phase nature on the sedimentation stability as well as coagulation structure of titanium phosphate (TP) nanoparticles in polymer suspensions has been investigated. Two systems are considered: (i). TP suspension in toluene/ethyl cellosolve mixed solution of ephoxy resin E-40 and (ii). multicomponent system, ferric oxide, talc and TP suspension in toluene/ethyl cellosolve solution of E-40, as a model of the practical varnish-paint systems. For the case of a polar solvent, a unique phenomenon, extremal dependence of the strength of model systems on the concentration TP, is detected and increase of sedimentation stability of TP organic suspensions with time of contact of TP with a solvent is observed. Data of FTIR-spectroscopy show that phenomena detected result from the formation adsorption shell possessing high structural viscosity on TP nanopaticles.
Asunto(s)
Polímeros/química , Titanio/química , Compuestos Férricos/química , Cinética , Modelos Químicos , Nanotecnología , Espectrofotometría Infrarroja , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Factores de TiempoRESUMEN
Experiments with human hepatoma PLC/PRF/5 cells and human embryo skin fibroblasts involving the use of three different tests (colony formation, Trypan blue exclusion, labeled thymidine incorporation) have demonstrated a significantly higher photosensitizing activity of chlorin e6 conjugates with internalizable ligands as compared to that of chlorin e6 itself. Receptor-mediated internalization of chlorin e6 conjugates ensures a greater photosensitization of cells than binding of those conjugates to cell surface receptors. The suitability of such conjugates that permit the delivery of a photosensitizer to sensitive intracellular targets is discussed.
Asunto(s)
Fármacos Fotosensibilizantes/farmacología , Porfirinas/farmacología , Células Cultivadas , Clorofilidas , Fibroblastos/efectos de los fármacos , Fibroblastos/efectos de la radiación , Humanos , Fotoquímica , Fotoquimioterapia , Fármacos Fotosensibilizantes/metabolismo , Porfirinas/metabolismo , Receptor de Insulina/metabolismo , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/efectos de la radiaciónRESUMEN
A soluble construct consisting of a plasmid carrying the gene of the SV40 large T-antigen and an insulin-poly-L-lysine conjugate is able to selectively transfect PLC/PRF/5 human hepatoma cells which possess insulin receptors. Transfection can be efficiently competed by excess free insulin. To examine intracellular transport of the construct, it was fluorescently labeled and its accumulation on and in cells visualized by video-enhanced microscopy and quantitative confocal laser scanning microscopy. After 2 h at 37 degrees C, the labeled construct was found predominantly in intracellular acidic compartments, with a substantial portion of fluorescence localized both near and in the cell nucleus. Binding, endocytosis, and nuclear localization of the labeled conjugate could all be competed by excess free insulin, thus indicating that entry of the conjugate into cells was specifically mediated by the insulin receptor.