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.