Open Access Kent State (OAKS)

Magnetic resonance imaging (MRI) scans use a combination of radio waves and magnetic fields to create an image of tissues within the body. While MRI is proven effective it only has limited use as to which tissue structures can be accurately resolved. Using contrast agents in MRI, it is possible to gain enhanced detail in acquired images to help resolve disease symptoms and tissue activity and improve the signal of tissues during a scan. Contrast agents are used in patients with Multiple Sclerosis to detect lesions in brain tissue. Issues with current contrast agents is their lack of specificity and toxicity at relatively low doses. Recently, a new nanoparticle, a gadolinium-based nanoparticle (GdNP). GdNP is approximately ten times stronger than typical contrast agents allowing it to provide the same contrast enhancement with ten percent of the typically required concentration. Targeting agents further decrease the number of molecules needed for desired image enhancement by binding to specific areas of the tissues being studied. This research is based around developing and evaluating nanoparticle-targeting agents as contrast enhancing probes with tissue specificity. The albumin binding protein, Evans blue (EB), have been attached to contrast enhancing nanoparticles. EB targets serum albumin (SA) in the blood vessels when injected intraperitoneally. We present in vivo MRI and microscopic data detailing development of this new probe designed to enhance signal from the neurovasculature of a mouse brain.

MRI scans use a combination of radio waves and magnetic fields to create an image of tissues within the body. In recent experiments, MRI is being used to image the vasculature of the brain and parts of the hypothalamus. Using contrast agents in MRI, it is possible to gain enhanced detail in acquired images. A contrast agent can improve the signal of tissues during a scan. The typical agent used is Magnevist (Gadolinium-DTPA). One issue with Magnevist is that the gadolinium portion can become toxic by becoming unattached from the rest of the molecule. The Kent State Chemistry Department has recently synthesized two new nanoparticles, a gadolinium-based nanoparticle (GdNP) and a gold-based nanoparticle. GdNP is approximately ten times stronger than Gd-DTPA allowing the GdNP to provide the same contrast enhancement with ten percent of the concentration needed with Magnevist. Targeting agents further decrease the number of molecules needed for the desired image, by binding to specific areas of the tissues being researched. This reduces the toxicity of the Gd by having less enter the body. The targeting agents used are fluorogold (FG) and evans blue (EB). FG targets neuroendocrine cells in the hypothalamus while EB targets serum albumin (SA) in the blood vessels. The nanoparticles being worked with bind to EB or FG, allowing the SA or the neuroendocrine cells to contrast more with the surrounding tissue. Beyond MRI, these nanoparticle techniques can also be used in microscopy.