ABSTRACT
Cellular labeling through the use of dyes is of great interest to the biomedical sciences for the characterization of the location and distribution of biomolecules and also for the tracking of the course of biological processes in both health and illness. This paper reports the synthesis, characterization, and subsequent evaluation as metal sensors and cell staining probes of four aza-BODIPY compounds [herein referred to as 7(a-d)]. Compounds 7(b-d) were found to display an outstanding selectivity for Cu(II) because their emission band at 720 nm was progressively quenched by this metal, presenting fluorescence quenching between 75 and 95%. On the other hand, cell imaging studies with pancreatic ß-cells proved that aza-BODIPYs 7a and 7b showed selectivity for the cytoplasm, while 7c and 7d were selective for the cell membrane. Moreover, aza-BODIPY 7b allowed to characterize in a clear way a lipotoxic condition mediated by saturated fatty acids, a critical phenomenon on ß-cell damage associated with diabetes mellitus type II. Taken together, the presented results highlight the obtained aza-BODIPY compounds as selective sensing/staining probes with the potential to be used in the biomedical field.
ABSTRACT
This study reports the synthesis of thin polymeric films by the layer-by-layer deposition and covalent cross-linking of polyvinyl dimethylazlactone and polyethylene imine, which were functionalized with lauric (12-C), myristic (14-C), and palmitic (16-C) saturated fatty acids, whose high levels in the bloodstream are correlated with insulin resistance and the potential development of type 2 diabetes mellitus. Aiming to assess the effect of the fatty acids on the adhesion and proliferation of Langerhans ß-cells, all prepared films (35 and 35.5 bilayers with and without functionalization with the fatty acids) were characterized in terms of their physical, chemical, and biological properties by a battery of experimental techniques including 1H and 13C NMR, mass spectrometry, attenuated total reflectance-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, atomic force microscopy, cell staining, and confocal laser scanning microscopy among others. In general, the developed films were found to be nanometric, transparent, resistant against manipulation, chemically reactive, and highly cytocompatible. On the other hand, in what the effect of the fatty acids is concerned, palmitic acid was found to impair the proliferation of the cultured ß-cells, contrary to its homologues which did not alter this biological process. In our opinion, the multidisciplinary study presented here might be of interest for the research community working on the development of cytocompatible 2D model substrates for the safe and reproducible characterization of cell responses.
ABSTRACT
Photodynamic therapy (PDT) has emerged as an alternative and promising noninvasive treatment for cancer. It is a two-step procedure that uses a combination of molecular oxygen, visible light, and photosensitizer (PS) agents; phthalocyanine (Pc) was supported over titanium oxide but has not yet been used for cell inactivation. Zinc phthalocyanine (ZnPc) molecules were incorporated into the porous network of titanium dioxide (TiO(2)) using the sol-gel method. It was prepared from stock solutions of ZnPc and TiO(2). ZnPc-TiO(2) was tested with four cancer cell lines. The characterization of supported ZnPc showed that phthalocyanine is linked by the N-pyrrole to the support and is stable up to 250°C, leading to testing for PDT. The preferential localization in target organelles such as mitochondria or lysosomes could determine the cell death mechanism after PDT. The results suggest that nanoparticulated TiO(2) sensitized with ZnPc is an excellent candidate as sensitizer in PDT against cancer and infectious diseases.
