RESUMEN
Surface-enhanced Raman scattering (SERS) is a unique spectroscopy that can offer high-sensitive detection for many molecules. Herein, the Au particles deposited on carbon nanofiber-encapsulated magnetic Ni nanoparticles (NPs) (Ni@CNFs@Au) have been successfully synthesized for SERS measurements. The Ni@CNFs@Au substrates have the advantages of a high SERS sensitivity and good magnetic response. The Ni@CNFs could be directly obtained from CO2 hydrogenation on a Ni catalyst, which has been characterized as having rich carboxylic acid groups, graphitic structures, and a high surface area. The Ni@CNFs surface could effectively increase the density of hotspots during Au NP aggregation and influence the morphology of the Au nanostructures. The spherical shape, oval shape, and coral-like Au nanostructures were prepared on Ni@CNFs with various Au concentrations. Brunauer-Emmett-Teller, zeta potential, high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy measurements were used to characterize the Ni@CNFs@Au samples. The Au NPs deposited on the Ni@CNFs presented a suitable oval shape, and an average size of â¼30-40 nm. The size allowed surprisingly ultrasensitive SERS detection of rhodamine 6G (R6G) with a resolution of approximately a single molecule under an excitation wavelength of 532 nm. Using 785 nm excitation, a low R6G concentration of â¼1 × 10-14 M was detected. Moreover, the Ni@CNFs@Au substrates could be rapidly magnetically separated after adsorption. Phenylalanine and tyrosine amino acids, which are associated with the liver disease, were examined using SERS with the Ni@CNFs@Au substrate. Ultralow concentrations of â¼1 × 10-11 M for phenylalanine and â¼1 × 10-13 M for tyrosine were clearly measured. The Ni@CNFs@Au substrates exhibited applicability as excellent SERS detection platforms that combine high-sensitivity and rapid magnetic separation for various adsorption molecules.
Asunto(s)
Aminoácidos Aromáticos/análisis , Carbono/química , Oro/química , Nanopartículas del Metal/química , Nanofibras/química , Rodaminas/análisis , Espectrometría Raman/métodos , Aminoácidos Aromáticos/química , Límite de Detección , Imanes/química , Rodaminas/químicaRESUMEN
A one-step process for the synthesis of hydrophilic carbon nanofibers (CNFs) through CO2 hydrogenation on NiNa/Al2O3 was developed for the loading and targeted delivery of the anticancer drug doxorubicin (DOX). CNFs that were synthesized on NiNa/Al2O3 for 9 h at 500 °C exhibited an adequate magnetic response and a large content of hydrophilic oxygen-containing functional groups on the carbon surface, resulting in excellent colloidal solution. The CNF material exhibited a highly efficient capacity for DOX adsorption, particularly at pH 9.0. The loading and release of DOX was strongly pH dependent, possibly due to electrostatic and π-π stacking interactions between DOX and CNF sample. The Langmuir isotherm and pseudo second-order kinetics of DOX-loaded CNFs were well-modeled for the process of DOX adsorption. DOX-loaded CNF targeted cancer cells more selectively and effectively than free DOX and exhibited a marked tendency to kill HeLa cancer cells and reduced toxicity to normal human primary fibroblast (HPF) cells.