The safety of imported seafood products because of the contamination of prohibited substances, including crystal violet (CV) and malachite green (MG), raised a great deal of concern in the United States. In this study, a fractal-like gold nanostructure was developed through a self-assembly process and the feasibility of using surface-enhanced Raman spectroscopy (SERS) coupled with this nanostructure for detection of CV, MG, and their mixture (1:1) was explored. SERS was capable of characterizing and differentiating CV, MG, and their mixture on fractal-like gold nanostructures quickly and accurately. The enhancement factor of the gold nanostructures could reach an impressive level of approximately 4 x 10(7), and the lowest detectable concentration for the dye molecules was at approximately 0.2 ppb level. These results indicate that SERS coupled with fractal-like gold nanostructures holds a great potential as a rapid and ultra-sensitive method for detecting trace amounts of prohibited substances in contaminated food samples.
Glioblastoma
(GBM) is one of the deadliest primary brain malignant
tumors with a bleak prognosis. Craniotomy surgical resection followed
by radiotherapy and chemotherapy was still the standard therapeutic
strategy for GBM. As a target alkylating agent, temozolomide (TMZ)
was utilized in the therapy of GBM for decades. However, effective
treatment for GBM is stymied by rapid acquired resistance and bone
marrow suppression. Here, we synthesize a tetrahedral framework nucleic
acid (tFNA) nanoparticle that can carry TMZ to enhance the lethality
on four GBM cell lines via activating the cell apoptosis and autophagy
pathway. Our nanoparticle, namely, tFNA-TMZ, shows a more obvious
efficacy in killing TMZ-sensitive cells (A172 and U87) than single-agent
TMZ. Besides, tFNA-TMZ was able to attenuate drug resistance in TMZ-resistant
cells (T98G and LN-18) via downregulating the expression of O6-methylguanine-DNA-methyltransferase.
Furthermore, we modified the tFNA with GS24, a DNA aptamer that can
specially bind to transferrin receptor in the cerebral vascular endothelial
cell of mouse and enable the tFNA nanoparticle to cross the blood–brain
barrier. In summary, our results demonstrated that tFNA-TMZ has a
promising role as a nanoscale vehicle to deliver TMZ to enhance the
efficacy of GBM.
A simple but highly specific immunoassay system for goat anti-human IgG has been developed using gold nanoparticles and microfluidic techniques. The assay is based on the deposition of gold nanoparticles that are coated with protein antigens in the presence of their corresponding antibodies to microfluidic channel surface. The effects of time accumulation, the flow velocity, and the concentration of antibodies to the red light absorption percentage (RAP) of deposition were investigated with an ordinary optical microscope. By controlling the reaction time and flow velocity, a dynamic range of 3 orders of magnitude and a detection sensitivity of 10 ng ml(-1) of goat anti-human IgG were achieved. Because of its simplicity and flexibility, this new technique should be useful for fast, highthroughput screening of antibodies in clinical diagnostic applications.
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