ABSTRACT
Visualizing the biodistribution of pesticides inside living cells is great importance for enhancing targeting of pesticides. Here we reported for the first time that gold nanorods (Au NRs) with size of 39.4 nm x 11.3 nm could be used as a fluorescent tracer to examine the distribution of a typical herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), in tobacco bright yellow 2 (BY-2) cells. The nanostructures of hybrid materials were analyzed by using Raman spectra and X-ray photoelectron spectroscopy (XPS), including spectra assignments and electronic property. These data revealed 2,4-D has successfully conjugated MP-Au NRs according to Raman and XPS. The biodistribution of the conjugates inside BY-2 cells was directly examined at 12 and 24 h by the two-photon microscopy. The intensity of two-photon luminescence (TPL) inside cells demonstrated that the conjugates could be localized and excluded by BY-2 cells. Thus, this labeling approach opens up new avenues to the facile and efficient labeling of pesticides.
Subject(s)
2,4-Dichlorophenoxyacetic Acid/pharmacokinetics , Gold/chemistry , Nanoconjugates/chemistry , Nanotubes/chemistry , Nicotiana/metabolism , Cells, Cultured , Crystallization/methods , Materials Testing , Microscopy, Fluorescence/methods , Molecular Imaging/methods , Nanoconjugates/ultrastructure , Nanotubes/ultrastructure , Particle Size , Pesticides/pharmacokinetics , Subcellular Fractions/chemistry , Subcellular Fractions/metabolism , Subcellular Fractions/ultrastructure , Nicotiana/chemistryABSTRACT
Gold nanoparticles (Au NPs) have drawn significant interest because of their antisotropic physical properties in biomedical applications. In this paper, we reported the application of bamboo (Bambusa chung) leaf extracts, previously not exploited, in the synthesis of Au NPs at ambient temperature. The average dimension of quasi-spherical Au NPs was 28.8±4.5 nm by transmission electron microscopy (TEM). The UV-vis spectroscopy gave an optimal reaction time of 180 min in the process of bioreduction. The organic shell of Au NPs was characterized by Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA), suggesting that the main compositions of the organic shell were hydroxyflavones. The X-ray diffraction (XRD) studies indicated the Au NPs were (111) oriented. This eco-friendly method for the synthesis of Au NPs was simple, amenable for large scale commercial production and biological applications to future in vivo imaging and cancer therapy.
Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Metal Nanoparticles/ultrastructure , Plant Extracts/chemistry , Plant Leaves/chemistry , Sasa/chemistry , Materials Testing , Particle Size , Surface PropertiesABSTRACT
Nearly monodisperse Au nanorods (NRs) with different aspect ratios were separated from home-synthesized polydisperse samples using a gradient centrifugation method. The morphology, size and its distribution, and photo-absorption property were analyzed by transmission electron microscopy, atomic force microscopy and UV-visible spectroscopy. Subsequently, using colloidal Au NRs (36.2 nm ×10.7 nm) with 97.4% yield after centrifugation and Au nanospheres (NSs) (22.9 ± 1.0 nm in diameter) with 97.6% yield as Au substrates, surface-enhanced Raman scattering (SERS) spectra of 2,4-dichlorophenoxyacetic acid (2,4-D) were recorded using laser excitation at 632.8 nm. Results show that surface enhancement factors (EF) for Au NRs and NSs are 6.2 × 10(5) and 5.7 × 10(4) using 1.0 × 10(-6) M 2,4-D, respectively, illustrating that EF value is a factor of ~10 greater for Au NRs substrates than for Au NSs substrates. As a result, large EF are a mainly result of chemical enhancement mechanisms. Thus, it is expected that Au NPs can find a comprehensive SERS application in the trace detection of pesticide residues.
Subject(s)
2,4-Dichlorophenoxyacetic Acid/analysis , Gold/chemistry , Metal Nanoparticles/chemistry , Spectrum Analysis, Raman/instrumentation , Transducers , 2,4-Dichlorophenoxyacetic Acid/chemistry , Equipment Design , Equipment Failure Analysis , Herbicides/analysis , Light , Scattering, RadiationABSTRACT
Understanding and visualizing the biodistribution of agricultural chemicals inside cells and living plants is very important for enhancing targeting and changing the application approaches of chemicals. Here, a novel material was synthesized through 2,4-dichlorophenoxyacetic acid functionalized small gold nanoparticles (2,4-D-MP-Au NPs). The successful modification of Au NPs (4.46 ± 0.70 nm) was ascertained by UV-vis, TEM, FTIR and XPS. TGA data revealed about 1197 molecules of 2,4-D were coupled to the surface of one Au nanoparticle, which was sufficient for bioapplications. The optical imaging of 2,4-D-MP-Au NPs inside BY-2 cells was directly examined, revealing that 2,4-D-MP-Au NPs could be internalized in BY-2 cells by the two-photo microscopy and endocytosis, as the internalization mechanism was energy dependent for 2,4-D-MP-Au NPs. Furthermore, the biodistribution of 2,4-D-MP-Au NPs in Ricinus cotyledons was measured, revealing that 2,4-D-MP-Au NPs could enter into mesophyll cells of Ricinus cotyledons; the cell recognition was enhanced after 2,4-D conjugated Au NPs. These results indicate that the conjugates have great potential for applications on bioimaging and biolabeling for agricultural chemicals in plant physiology.