RESUMO
Fluorophores with optimized nonlinear optical properties have become prominent as contrast labels in laser scanning microscopy (LSM). The purpose of this work is to report on a novel benzothiadiazole derivative, namely 4,7-bis(5-((9,9-dioctyl-9H-fluoren-2-yl)ethynyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (EFBT) and its optical performance when it is loaded into organic nanostructures intended as labels for LSM. Four different nanostructured labels were prepared: i) EFBT-loaded silica nanoparticles (SiNPs); ii) folate-bioconjugated SiNPs (SiNPs-FA); iii) EFBT-loaded PEGylated nanoparticles (NPs-PEG); and iv) EFBT-loaded folate-terminated PEGylated nanoparticles (NPs-PEG-FA). All these nanostructures are reported through a comparative study of their linear and nonlinear optical properties, including their performance as exogenous label agents in the cervical cancer cell line HeLa. This assessment of the performance of a specific fluorophore loaded into different nanostructured matrices (labels), and fairly compared under the same characterization conditions, including the LSM settings, is less common while previous reports had focused in comparing silica and PEGylated nanoparticles but loaded with different fluorophores. The results show that the internal molecular organization into each type of organic nanostructure impacted differently the properties of EFBT, where the silica matrix tend to preserve the optical performance of the fluorophore by preventing intermolecular interactions; in contrast, PEGylated nanoparticles favored molecular interactions and introduced non-radiative decay channels that degrades drastically the optical performance. Nevertheless, the use of functionalized ends entities produced a better cellular label uptake with PEGylated that with silica nanoparticles. In overall, the NPs-PEG-FA label produced the best HeLa imaging.
Assuntos
Nanopartículas , Tiadiazóis , Humanos , Células HeLa , Corantes Fluorescentes/química , Polietilenoglicóis/química , Ácido Fólico/química , Dióxido de Silício , Nanopartículas/químicaRESUMO
In this work, gold nanospheres functionalized with low weight organic molecules (4-aminothiphenol and cysteamine) were synthesized in a one-step method for their in vitro cytotoxic evaluation on HeLa cells. To enhance the biocompatibility of the cysteamine-capped GNPs, BSA was used due to its broad PH stability and high binding affinity to gold nanoparticles. Besides, the widely reported silica coated gold nanorods were tested here to contrast their toxic response against our nanoparticles coated with organic molecules. Our results shown, the viability measured at 1.9×10-5M did not show significant differences against negative controls for all the samples; however, the metabolic activity of HeLa cells dropped when they were exposed to silica gold nanorods in the range of concentrations from 2.9×10-7M to 3.0×10-4M, while in the cases of gold nanospheres, we found that only at concentrations below 1.9×10-5M metabolic activity was normal. Our preliminary results did not indicate any perceivable harmful toxicity to cell membrane, cytoskeleton or nucleus due to our nanospheres at 1.9×10-5M. Additional test should be conducted in order to ensure a safe use of them for biological applications, and to determine the extent of possible damage.
Assuntos
Ouro/toxicidade , Nanopartículas Metálicas/toxicidade , Compostos de Anilina/química , Sobrevivência Celular/efeitos dos fármacos , Cisteamina/química , Citoesqueleto/efeitos dos fármacos , Ouro/química , Células HeLa , Humanos , Nanopartículas Metálicas/química , Nanotubos/química , Nanotubos/toxicidade , Soroalbumina Bovina/química , Dióxido de Silício/química , Compostos de Sulfidrila/químicaRESUMO
Se estudian 30 recien nacidos de madres con colestasia intrahepatica del embarazo y 30 controles. Ambos grupos tienen niveles comparables de bilirrubinemia en los primeros seis dias de vida. Se encontro un numero importante de muestras de leche materna y inhiben la conjugacion de bilirrubina in vitro, pero no hubo relacion con los niveles de bilirrubina serica de los recien nacidos. La capacidad inhibitoria de la leche materna es directamente proporcional al contenido total de acidos grasos libres de las muestras analizadas