Steve Huntz Fung1,2, Edward S. Hui1, Feng Li1, Guoting Qin1, Diana U. Lo1, Rongmin Xia1, Zheng X. Li1,2, Brian E. O'Neill1,2, King C. Li1,2
1Department of Radiology, The Methodist Hospital, Houston, TX, United States; 2Department of Radiology, Weill Cornell Medical College, New York, United States
We have developed gadolinium-chelate functionalized gold nanoparticles (Gd-Au NP) as theranostic agents that can be detected by MRI to guide NIR laser therapy. By tuning the optical properties of Gd-Au NP to absorb in NIR, where tissue penetration of light is optimal, one can selectively heat tumor tissue that contain nanoparticles. We have taken into consideration expected spectral shift of surface plasmon resonance (SPR)-associated absorption from surface functionalization, and designed a good NIR absorber that doubles as a very good T1-contrast agent. In the design process, a new Gd-DTPA-based chelate-linker for conjugation to Au NP is proposed that has two thiol-Au binding sites and a longer linker segment than ones proposed in existing literature, which should allow for better immobilization and increased number of Gd-chelate conjugation to Au NP for better T1-relaxivity. MR relaxivity, UV-visible-NIR spectroscopy, and NIR laser heating data are presented.