U.S.-Egypt Cooperative Research: Chemical Synthesis of Magnetic Oxide Nanoparticles and Films, and Their evaluation for Sensing Applications.

0612150 Venkatesan描述：该奖项是为了支持马里兰大学学院公园物理系T.Venkatasen博士和埃及亚历山大市亚历山大大学Wegdan Ramadan Osman博士的合作研究。他们计划对磁性氧化物纳米颗粒的化学合成进行研究，包括粉末形式和支撑纳米颗粒薄膜的形式。智力价值：在过去的几年里，新的功能磁性氧化物领域的活动激增，如巨磁电阻锰氧化物、多铁性材料和稀磁半导体，因为它们预计具有许多新的应用潜力。关键问题是几何和物理长度尺度之间的相互作用，通过有限系统尺寸和小数目统计对结构和电子性质弛豫的影响。人们已经广泛地证明，当系统尺寸减小到一定的系统依赖极限以下时，它的物理性质会发生变化，并赋予它一个全新的性质--空间。这就需要研究纳米材料的应用潜力。磁性纳米材料的特征是具有新的和部分意想不到的磁性，例如，增强的剩磁或巨大的矫顽场。此外，磁化曲线可以取决于系统大小，该曲线是磁性材料的非本征行为的图像。纳米科学是组成科学和体系科学的耐人寻味的混合物。本研究旨在阐明这些现象，并开发控制它们的方法，以期达到应用的目的。PI将探索在地质、环境和农业等领域可能具有更广泛用途的传感应用。更广泛的影响：磁性纳米颗粒在生物医学和相关科学领域提供了几种有趣的可能性。它们的大小从1到100纳米的广泛和可控的范围允许它们标记到生物对象，如细胞、病毒、蛋白质或基因。此外，它们可以通过外部磁场梯度来操纵。考虑到磁场对人体组织的固有穿透性，因此能够运输、固定和控制磁性纳米颗粒或相应的标记生物实体。此外，磁性纳米粒子对时变磁场的共振响应导致能量从激发场向纳米粒子的显著转移，导致它们被加热，从而使其作为热疗剂成为可能。因此，可以使这些颗粒将局部热能传递到肿瘤等靶体；或者作为化疗和放射增强剂。磁性纳米粒子和相关流体系统在四个具体应用方面正在积极研究：磁分离、药物输送、热疗和磁共振成像(MRI)对比度增强。磁性纳米颗粒还被设想在农业、石油勘探等不同领域的许多其他应用。该项目得到了美国-埃及联合基金计划的支持，该计划为两国的科学家和工程师提供资助，以开展这些合作活动。

0612150 VenkatesanDescription: This award is to support a cooperative research by Dr. T. Venkatasen, Department of Physics, University of Maryland, College Park,Maryland and Dr. Wegdan Ramadan Osman, Alexandria University, Alexandria, Egypt. They plan to conduct research on the chemical synthesis of magnetic oxide nanoparticles both in the powder form and in the form of supported nanoparticle films. Intellectual Merit: There has been a surge of activity, over the past few years, in the field of new functional magnetic oxides such as colossal magnetoresistance manganites, multiferroics and diluted magnetic semiconductors due to their projected potential for a number of novel applications. The key issues are the interplay of geometric and physical length scales via the influence of finite system size and small number statistics on the structural and electronic property relaxations. It has been widely demonstrated that reduction in the system size below a certain system-dependent limit introduces changes in its physical properties and endows it with an entirely new property-space. This calls for examination of the application potential of the nanoscale materials. Magnetic nanomaterials are characterized by new and partially unexpected magnetic properties, such as, for example, enhanced remanence or a giant coercive field. Furthermore, the magnetization curve, which is a picture of the extrinsic behavior of a magnetic material, may depend on the system size. Nanoscience is an intriguing admixture of the science of the constituent and the system. This research aims at elucidating these phenomena and developing means to control them in the interest of applications. The PIs will explore sensing applications which could be of broader use in fields such as geology, environment, and agriculture. Broader Impact: Magnetic nanoparticles offer several interesting possibilities in the field ofbiomedicine and the related science. The broad and controllable range of their size from 1-100 nanometers allows their tagging to biological objects such as cells, viruses, proteins or genes. Moreover, they can be manipulated by an external magnetic field gradient. Given the intrinsic penetrability of magnetic fields into human tissue, thus enabling the transport, immobilization and control of the magnetic nanoparticles or the corresponding tagged biological entities. Also, the resonant response of magnetic nanoparticles to time-varying magnetic field causes significant transfer of energy from the exciting field to the nanoparticle, resulting in their heating and making possible their use as hyperthermia agents. Thus these particles can be made to deliver localized thermal energy to targeted bodies such as tumors; or as chemotherapy and radiotherapy enhancement agents. Magnetic nanoparticles and related fluid systems are being actively investigated in the context of four specific applications: magnetic separation, drug delivery, hyperthermia treatments and magnetic resonance imaging (MRI) contrast enhancement. Many other applications of magnetic nanoparticles have been envisaged in diverse fields such as agriculture, oil explorations.This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.