¹²⁵I-Labeled Gold Nanorods for Targeted Imaging of Inflammation

Abstract

For better examination of inflammation, we designed inflammation-targeted nuclear and optical dual-modality contrast agents prepared by I-125 radiolabeling of gold nanorods (GdNRs) conjugated with anti-intercellular adhesion molecule 1 (ICAM-1) antibody. The bioactivity and specific binding of the PEGylated 125I-ICAM-GdNRs conjugates to the ICAM-1 was validated through ELISA testing. Inflammation-targeted imaging was then conducted on an adjuvant-induced arthritic rat model which demonstrated an elevation of ICAM-1 level in the affected ankle joints. Facilitated by the I-125 radioisotope and the whole-body imaging via the Gamma camera, the time-dependent distribution of the systemically injected agent as well as the uptake of the agent in the inflammatory articular tissues could be examined conveniently and quantitatively. The success in targeted delivery of gold nanoparticles to inflammatory tissue enables both nuclear and optical imaging of inflammation at molecular or cellular level. Other than diagnosis, radiolabeled gold nanoparticles also hold promise for targeted therapy of a variety of disorders.

Visualization of Macrophage Recruitment to Inflammation Lesions using Highly Sensitive and Stable Radionuclide-Embedded Gold Nanoparticles as a Nuclear Bio-Imaging Platform

“…Numerous other reports have shown the labeling strategy of bonding radioiodine onto gold nanoparticles through direct incorporation 15-21. However, these methods allow only a small number of radioiodine labels to be incorporated on AuNPs; in addition, maintaining the stability of labeled radioiodine remains challenging within in vivo environments.…”

Plasmonic Nanoparticles with Quantitatively Controlled Bioconjugation for Photoacoustic Imaging of Live Cancer Cells

“…This radiolabeling procedure has been proven to be efficient and stable as a result of the high affinity and strong binding of iodide ions with the surface of AuNPs 27. In the experiment, the 125 I‐labeled fAuNPs were delivered into human prostate cancer cells (DU145) for quantitative evaluation of cellular uptake efficiency.…”

“…This, however, imposes demanding requirements on the resolution and sensitivity of PAI because most cancer cells are very small in size (≈10 μm) and exhibit little endogenous absorption contrast (except melanoma cells) 21, 22, 23, 24, 25, 26. To achieve high‐sensitivity PAI at the cellular level, exogenous contrast agent is preferably used to enhance optical absorption and amplify photoacoustic signal generation efficiency 27, 28, 29…”

Radio‐Labeled Nanoparticles for Biomedical Imaging

“…Clearance studies showed fast renal elimination as confirmed by Tem of urine samples. Interestingly, the radiolabeling of 125 I was directly on the gold surface with good yield and stability [84][85][86]. There were about six 125 I isotopes per AuNp with serum stability tests showing more than 85% of 125 I remaining intact on AuNps after a 24 h incubation at 37°C, indicating the potential of this AuNp for tumor SpeCT imaging [87].…”