RESUMO
A new strategy for preparing luminescent and intelligent gold nanodots based on supramolecular self-assembly is described in this paper. The supramolecular self-assembly was initiated through electrostatic interactions and ion pairing between palmitic acid and hyperbranched poly(ethylenimine). The resulting structures not only have the dynamic reversible properties of supramolecules but also possess torispherical and highly branched architectures. Thus they can be regarded as a new kind of ideal nanoreactor for preparing intelligent Au nanodots. By preparing Au nanodots within this kind of supramolecular self-assembly, the environmental sensitivity of intelligent polymers and the optical, electrical properties of Au nanodots can be combined, endowing the Au nanodots with intelligence. In this paper, a supramolecular self-assembly process based on dendritic poly(ethylenimine) and palmitic acid was designed and then applied to prepare fluorescent and size-controlled Au nanodots. The pH response of Au nanodots embodied by phase transfer from oil phase to water phase was also investigated.
Assuntos
Ouro/química , Substâncias Luminescentes/química , Ácido Palmítico/química , Polietilenoimina/química , Pontos Quânticos , Concentração de Íons de Hidrogênio , Nanotecnologia/métodos , Eletricidade EstáticaRESUMO
In this work, polyaniline (PANI) nanofibrous networks were prepared using ionic liquid (IL), 1-hexadecyl-3-methylimidazolium chloride (C16MIMCl), as a template through oxidative polymerization of aniline with ammonium persulfate. The resulting PANI was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis, and FTIR. It was indicated that the as-prepared PANI was in the emeraldine form and its morphology strongly depended on the molar ratio of aniline/C16MIMCI. A possible mechanism for the formation of PANI nanofibrous networks was that the ordered micro-domains of the IL acted as template to direct the growth of the nanostructures.
Assuntos
Compostos de Anilina/síntese química , Compostos de Anilina/química , Condutividade Elétrica , Indicadores e Reagentes , Íons , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Polímeros , Espectrofotometria , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Dopamine (DA) is one of the most important neurotransmitters present in brain tissues and body fluids of mammals. The change in the concentration levels has been associated with various diseases and disorders. Thus, sensitive and selective determination of DA is much preferred. In this work, sandwich-type electrochemical biosensor was developed, in which phenylboronic acid immobilized onto gold electrodes was used to capture DA. The anchored DA was then derivatized with biotin for the attachment of ferrocene-capped gold nanoparticle/streptavidin conjugates. The voltammetric responses were found to be proportional to the concentrations of DA ranging from 0.5 to 50 nM. A detection limit of 0.2 nM was achieved, which is 1~2 orders of magnitude lower than those achievable at various chemically modified electrodes. Analytical merits (e.g., dynamic range, reproducibility, detection level, selectivity and interference) were evaluated. The feasibility of the method for analysis of DA in artificial cerebrospinal fluid and dopamine hydrochloride injection has been demonstrated.
Assuntos
Técnicas Biossensoriais/instrumentação , Condutometria/instrumentação , Dopamina/análise , Compostos Ferrosos/química , Ouro/química , Nanopartículas Metálicas/química , Estreptavidina/química , Amplificadores Eletrônicos , Materiais Revestidos Biocompatíveis/síntese química , Eletrodos , Desenho de Equipamento , Análise de Falha de Equipamento , Nanopartículas Metálicas/ultraestrutura , Metalocenos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Ibuprofen- (IBU) loaded biocompatible poly(lactic-co-glycolic acid) (PLGA) films were prepared by spreading polymer/ibuprofen solution on the nonsolvent surface. By controlling the weight ratio of drug and polymer, different drug loading polymer films can be obtained. The synthesized ibuprofen-loaded PLGA films were characterized with scanning electron microscopy, powder X-ray diffraction, and differential scanning calorimetry. The drug release behavior of the as-prepared IBU-loaded PLGA films was studied to reveal their potential application in drug delivery systems. The results show the feasibility of the as-obtained films for controlling drug release. Furthermore, the drug release rate of the film could be controlled by the drug loading content and the release medium. The development of a biodegradable ibuprofen system, based on films, should be of great interest in drug delivery systems.