The benefits of folic acid-modified gold nanoparticles in CT-based molecular imaging: radiation dose reduction and image contrast enhancement

X-ray computed tomography (CT) requires an optimal compromise between image quality and patient dose. While high image quality is an important requirement in CT, the radiation dose must be kept minimal to protect the patients from ionizing radiation-associated risks. The use of probes based on gold nanoparticles (AuNPs) along with active targeting ligands for specific recognition of cancer cells may be one of the balanced solutions. Herein, we report the effect of folic acid (FA)-modified AuNP as a targeted nanoprobe on the contrast enhancement of CT images as well as its potential for patient dose reduction. For this purpose, nasopharyngeal KB cancer cells overexpressing FA receptors were incubated with AuNPs with and without FA modification and imaged in a CT scanner with the following X-ray tube parameters: peak tube voltage of 130�KVp, and tube current�time products of 60, 90, 120, 160 and 250�mAs. Moreover, in order to estimate the radiation dose to which the patient was exposed during a head CT protocol, the CT dose index (CTDI) value was measured by an X-ray electrometer by changing the tube current�time product. Raising the tube current�time product from 60 to 250�mAs significantly increased the absorbed dose from 18�mGy to 75�mGy. This increase was not associated with a significant enhancement of the image quality of the KB cells. However, an obvious increase in image brightness and CT signal intensity (quantified by Hounsfield units HU) were observed in cells exposed to nanoparticles without any increase in the mAs product or radiation dose. Under the same Au concentration, KB cells exposed to FA-modified AuNPs had significantly higher HU and brighter CT images than those of the cells exposed to AuNPs without FA modification. In conclusion, FA-modified AuNP can be considered as a targeted CT nanoprobe with the potential for dose reduction by keeping the required mAs product as low as possible while enhancing image contrast. © 2017 Informa UK Limited, trading as Taylor & Francis Grou

Occurrence of aflatoxin M 1 in raw, pasteurized and UHT milk commercialized in Esfahan and Shahr-e Kord, Iran

Aflatoxin M 1 , Milk, ELISA,

Carbon Quantum Dots and Applications in Photocatalytic Energy Conversion

Quantum dots (QDs) generally refer to nanoscale particles of conventional semiconductors that are subject to the quantum-confinement effect, though other nanomaterials of similar optical and redox properties are also named as QDs even in the absence of strictly defined quantum confinement. Among such nanomaterials that have attracted tremendous recent interest are carbon dots, which are small carbon nanoparticles with some form of surface passivation, and graphene quantum dots in various configurations. In this article, we highlight these carbon-based QDs by focusing on their syntheses, on their photoexcited state properties and redox processes, and on their applications as photocatalysts in visible-light carbon dioxide reduction and in water-splitting, as well as on their mechanistic similarities and differences