RESUMO
Magnetic sensing utilizes the detection of biomolecule-conjugated magnetic nanoparticles (MNPs). Our new strategy offers a novel approach to magnetic sensing where in situ conversion produces a "loss of signal" in the sensing device. This report demonstrates the enzymatic conversion of Fe3O4 MNPs to a non-magnetic precipitate via reduction by l-ascorbic acid generated by the action of alkaline phosphatase.
Assuntos
Fosfatase Alcalina/química , Ácido Ascórbico/química , Nanopartículas de MagnetitaRESUMO
The research strategy described in this manuscript harnesses the attractive properties of hydrogels, gold nanorods (Aurods), and magnetic nanoparticles (MNPs) by synthesizing one unique multi-responsive nanostructure. This novel hybrid structure consists of silica-coated magnetic particles encapsulated within a thermo-responsive P(NIPAM-co-AA) hydrogel network on which Aurods are assembled. Furthermore, this research demonstrates that these composite particles respond to several forms of external stimuli (temperature, pH, light, and/or applied magnetic field) owing to their specific architecture. Exposure of the hybrid particles to external stimuli led to a systematic and reversible variation in the hydrodynamic diameter (swelling-deswelling) and thus in the optical properties of the hybrid particles (red-shifting of the plasmon band). Such stimuli-responsive volume changes can be effectively exploited in drug-delivery applications.
RESUMO
The proximal promoter region of the human vascular endothelial growth factor (VEGF) gene contains a guanine-rich strand that can act as a transcriptional silencer by forming an intramolecular G-quadruplex. In this study, we compared two perylene monoimide derivatives, PM1 and PM2, with the well-studied perylene diimide derivative, PIPER, and the well-studied porphyrin derivative, TmPyP(4), with regard to G-quadruplex formation, G-quadruplex binding selectivity, and human VEGF gene silencing in A549 lung cancer cells. The results show that these perylene derivatives can preferentially induce intramolecular G-quadruplex formation from a duplex containing the VEGF G-quadruplex motif in vitro. Incubating A549 lung cancer cells with these perylene derivatives, especially PM2, led to the reduction of both VEGF mRNA and VEGF protein. This study might provide the foundation for the rational design and development of new perylene derivatives as effective anti-angiogenesis agents for cancer therapy.
Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Imidas/química , Perileno/análogos & derivados , Fator A de Crescimento do Endotélio Vascular/biossíntese , Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Regulação para Baixo , Desenho de Fármacos , Quadruplex G , Inativação Gênica , Células HeLa , Humanos , Imidas/farmacologia , Modelos Biológicos , Modelos Químicos , Perileno/química , Perileno/farmacologia , Reação em Cadeia da Polimerase/métodos , RNA Mensageiro/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Three new perylene derivatives with branched ionizable side chains were synthesized, and their G-quadruplex binding specificities were compared by spectroscopic and electrophoretic analysis with two well-studied G-quadruplex ligands: PIPER and TmPyP4. The value of pH and consequent charge formation and self-aggregation of these perylene derivatives influences not only the type of G-quadruplex formation, but also the G-quadruplex binding selectivity.
