Unwanted exposures to high-energy or ionizing radiation can be hazardous to health. Prolonged or accumulated radiation dosage from either particle-emissions such as alpha/beta, proton, electron, neutron emissions, or high-energy electromagnetic waves such as X-rays/γ rays, may result in carcinogenesis, cell mutations, organ failure, etc. To avoid occupational hazards from these kinds of exposures, researchers have traditionally used heavy metals or their composites to attenuate the radiation. However, protective gear made of heavy metals are not only cumbersome but also are capable of producing more penetrative secondary radiations which requires additional shielding, increasing the cost and the weight factor. Consequently, significant research efforts have been focused toward designing efficient, lightweight, cost-effective, and flexible shielding materials for protection against radiation encountered in various industries (aerospace, hospitals, and nuclear reactors). In this regard, polymer composites have become attractive candidates for developing materials that can be designed to effectively attenuate photon or particle radiation. In this paper, we review the state-of-the-art of polymer composites reinforced with micro/nanomaterials, for their use as radiation shields.

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Lead is commonly used in medical radiology departments as a shielding material. Lead‐based protective materials are also used by clinical personnel during X‐ray image‐guided interventional radiology (IVR) procedures. However, lead is extremely toxic and prolonged exposure to it can result in serious health concerns. Polymer composites, on the other hand, can be designed to be lead‐free in addition to being lightweight, conformable, cost effective, and potentially capable of significantly attenuating X‐rays. Nanomaterials have unique material properties that can be exploited to develop novel lead‐free radiation‐protection materials. In this study, polydimethylsiloxane (PDMS) nanocomposites were fabricated using different weight percentages (wt %) of bismuth oxide (BO) nanopowder. The attenuation properties of the nanocomposites were characterized using diagnostic X‐ray energies from 40 to 150 kV tube potential and were compared to the attenuation characteristics of 0.25‐mm‐thick pure lead sheet. The PDMS/BO nanocomposite (44.44 wt% of BO and 3.73‐mm thick) was capable of attenuating all the scattered X‐rays generated at a tube potential of 60 kV, which is the beam energy commonly employed in IVR. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013

Gold nanoparticles (AuNPs) are a focus of growing medical research applications due to their unique chemical, electrical and optical properties. Because of uncertain toxicity, “green” synthesis methods are emerging, using plant extracts to improve biological and environmental compatibility. Here we explore the biodistribution of green AuNPs in mice and prepare a physiologically-based pharmacokinetic (PBPK) model to guide interspecies extrapolation. Monodisperse AuNPs were synthesized and capped with epigallocatechin gallate (EGCG) and curcumin. 64 CD-1 mice received the AuNPs by intraperitoneal injection. To assess biodistribution, groups of six mice were sacrificed at 1, 7, 14, 28 and 56 days, and their organs were analyzed for gold content using inductively coupled plasma mass spectrometry (ICP-MS). A physiologically-based pharmacokinetic (PBPK) model was developed to describe the biodistribution data in mice. To assess the potential for interspecies extrapolation, organism-specific parameters in the model were adapted to represent rats, and the rat PBPK model was subsequently evaluated with PK data for citrate-capped AuNPs from literature. The liver and spleen displayed strong uptake, and the PBPK model suggested that extravasation and phagocytosis were key drivers. Organ predictions following interspecies extrapolation were successful for rats receiving citrate-capped AuNPs. This work lays the foundation for the pre-clinical extrapolation of the pharmacokinetics of AuNPs from mice to larger species.

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In the published article cited above, the below errors were discovered.Page 4940 the 2nd sentence under the sub-section Material Characterization:The nanocomposites with 37.73 and 44.44 wt % of BO in PDMS were sectioned with a diamond knife on a Reichert Ultracut E ultramicrotome fitted with a cryochamber (model FC 4E, Reichert-Jung, Wien, Austria) at 120 C.The text was incorrect and should have read:The nanocomposites with 37.73 and 44.44 wt % of BO in PDMS were sectioned with a diamond knife on a Reichert Ultracut E ultramicrotome fitted with a cryochamber (model FC 4E, Reichert-Jung, Wien, Austria) at 2120 C.Page 4944 (top): The caption was incorrect and should have read:

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