A rapid, simple and sensitive biosensor system for tetracycline detection is very important in food safety. In this paper we developed a label-free aptasensor for electrochemical detection of tetracycline. According to the electrochemical impendence spectroscopy (EIS) analysis, there was a linear relationship between the concentration of tetracycline and the electron transfer resistance from 10 to 3000 ng ml−1 of the tetracycline concentration. The detection limit was 10 ng ml−1 in 15 min detection duration. The prepared aptasensor showed a good reproducibility with an acceptable stability in tetracycline detection. The recoveries of tetracycline in spiked milk samples were in the range of 88.1%–94.2%. The aptasensor has sensitivity 98% and specificity of 100%.
Nanoparticles (NPs) have been proven to be an effective delivery system with few side effects for anticancer drugs. In this study, curcumin-loaded NPs have been prepared by an ionic gelation method using chitosan (Chi) and pluronic®F-127 (PF) as carriers to deliver curcumin to the target cancer cells. Prepared NPs were characterized using Zetasizer, fluorescence microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Our results showed that the encapsulation efficiency of curcumin was approximately 50%. The average size of curcumin-loaded PF/Chi NPs was 150.9 nm, while the zeta potential was 5.09 mV. Cellular uptake of curcumin-loaded NPs into HEK293 cells was confirmed by fluorescence microscopy.
Drug delivery to cancer cells in chemotherapy is one of the most advanced research topics. The effectiveness of the current cancer treatment drugs is limited because they are not capable of distinguishing between cancer cells and normal cells so that they kill not only cancer cells but also normal ones. To overcome this disadvantage by profiting from the differences in physical and chemical properties between cancer and normal cells, nanoparticles (NPs) delivering a drug are designed in a specific manner such that they can distinguish the cancer cells from the normal ones and are targeted only to the cancer cells. Currently, there are various drug delivery systems with many advantages, but sharing some common disadvantages such as difficulty with controlling the size, low encapsulation capacity and low stability. With the development and success of DNA nanotechnology, DNA strands are used to create effective drug delivery NPs with precisely controlled size and structure, safety and high stability. This article presents our study on drug encapsulation in DNA nanostructure which loaded docetaxel and curcumin in a desire to create a new and effective drug delivery system with high biological compatibility.
Polymeric nanoparticles (NPs) prepared from poly(ethylene glycol)-block-poly (ε-caprolactone) (PEG–PCL) were fabricated by the modified nanoprecipitation method with and without sonication to entrap docetaxel (Doc) and curcumin (Cur). NPs were characterized in terms of morphology, size distribution, zeta potential, encapsulation efficiency and cytotoxicity. The particles have a ∼45–80 nm mean diameter with a spherical shape. The cellular uptake of the NPs was observed after 2 and 4 h of incubation by fluorescence of curcumin loaded with docetaxel. The cell viability was evaluated by an [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay on the Hela cell line. Doc and Doc–Cur NPs had higher cytotoxicity and a much lower IC50 value compared with free Doc or Cur after 24 and 48 h of incubation. Doc and Cur incorporated into the PEG–PCL NPs had the highest cytotoxicity in comparison with all other NPs and may be considered as an attractive and promising drug delivery system for cancer treatment.
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