My first major focus is the toxicology of nanoparticles, or nanotoxicology. For example, semiconductor quantum dots (QDs) have enormous potential for biomedical imaging due to tunable fluorescence emission, intense brightness, resistance to photobleaching, and the capability for multiplexed imaging.  Clinical development of these nanoparticles is impeded, however, by toxicity concerns directed towards the elemental composition of traditional QDs.  Yet, little is known about the actual mechanism of this toxicity and the most important parameters regarding toxicity have yet to be determined.  Moreover, more in depth understanding of the potential toxicity of nanometer sized materials is needed in order for nanoparticles to realize their full clinical potential.  This project focuses on understanding the toxicology of nanoparticles genomically to in vivo systemic toxicity.

A second area of research is evaluating the potential of using nanoparticles as vehicles for oral drug delivery.  Many therapeutics taken orally, especially drugs taken for among others, chemotherapy, osteoporosis, and cardiovascular disease, suffer from very poor bioavailability.  Absorption of nanoparticles into the blood stream could significantly increase the therapeutic payload to the target site.  In this project, we are using quantum dots as a model nanoparticle.  QDs are ideal particles for this study because their size is well controlled; their surface ligands can be easily modified; and, due to their brightness and photostability, can be monitored in real time.  The goal of this project is to provide the framework for the design of optimized nanoparticles for oral drug delivery.

Publications and Presentation

Publications:
Mohs AM, Nguyen T, Jeong EK, Feng Y, Emerson LL, Zong Y, Parker DL, Lu ZR. (2007) Pegylation of Gd-DTPA cystine copolymers optimizes pharmacokinetics and tissue retention for magnetic resonance angiography. Magn. Reson. Med. 58(1):110-118.

Mohs AM, Lu ZR. (2007) Gadolinium(III)-based blood pool contrast agents for magnetic resonance imaging: current status and clinical potential. Expert Opin. Drug. Deliv. 4(2):149-164.

Zong Y, Guo J, Ke T, Mohs AM, Parker DL, Lu ZR. (2006) Effect of size and charge on pharmacokinetics and in vivo MRI contrast enhancement of biodegradable polydisulfide Gd(III) complexes. J. Control. Release 112:350-356.

Lu ZR, Mohs AM, Zong Y, Feng Y. (2005) Polydisulfide Gd(III) chelates as biodegradable macromolecular magnetic resonance imaging contrast agents. Intl. J. Nanomed. 1:31-40.

Mohs AM, Zong Y, Guo J, Parker DL, Lu ZR. (2005) PEG-g-poly(GdDTPA-co-L-cystine): effect of PEG chain length on in vivo contrast enhancement in MRI. Biomacromolecules 6:2305-2311.

Zong Y, Wang X, Goodrich KC, Mohs AM, Parker DL, Lu ZR. (2005) Contrast-enhanced MRI with new biodegradable macromolecular Gd(III) complexes in tumor-bearing mice. Magn. Reson. Med. 53:835-842.

Mohs AM, Wang X, Zong Y, Goodrich KC, Parker DL, Lu ZR. (2004) PEG-g-poly(GdDTPA-co-L-cystine): A biodegradable macromolecular blood pool contrast agent for MR imaging. Bioconj. Chem. 15:1424 - 1430.

Presentations:
Mohs AM, Zong Y, Feng Y, Guo J, Parker DL, Lu ZR. PEG-g-(GdDTPA-co-L-cystine): novel biodegradable macromolecular contrast agents for MRI, Controlled Release Society Annual Meeting, 32nd Annual Meeting & Exposition of the Controlled Release Society; Miami, FL, June 2005.

Mohs AM, Zong Y, Parker DL, Lu ZR. PEG-g-poly(GdDTPA-co-L-cystine): effect of PEG chain length on in vivo contrast enhancement in MRI. MR Angio Club - The 17th Annual International Conference on Magnetic Resonance Angiography; Beijing, China, September 2005.

Zong Y, Guo J, Feng H, Sun Y, Mohs AM, Parker DL, Lu ZR. (Gd-DTPA)-cystine diethylester copolymers (GDCEP) as a biodegradable contrast agent for MR imaging. Controlled Release Society Symposium; Salt Lake City, UT, February 2005.

Mohs AM, Wang X, Zong Y, Goodrich KC, Parker DL, Lu ZR. Gd(III)DTPA-L-cystine-PEG copolymers: a biodegradable macromolecular agent for blood pool MR imaging, International Society of Magnetic Resonance in Medicine - 12th Scientific Meeting and Exposition; Kyoto, Japan, May 2004.

Zong Y, Wang X, Mohs AM, Goodrich KC, Lu ZR. MR imaging of a biodegradable polymeric contrast agent, cystine-DTPA-Gd complex. Controlled Release Society; Honolulu, HI, June 2004.

Zong Y, Mohs AM, Goodrich KC, Wang X, Parker DL, Lu ZR, Synthesis of Gd(III)DTPA-cystine a Gd(III) DTPA-cystine ethyl ester copolymers for MRI, Imaging in 2020; Jackson Hole, WY, September 2003.

Tekavek TN, Brueske CJ, Mohs AM, Westman AL, Schaller CP. Synthesis of molybdenum complexes of DACO' and pzpy'. 223rd ACS National Meeting; Orlando, FL, April 2002.