LANTHANIDE NANOPARTICLES AS MULTIMODAL IMAGING CONTRAST AGENTS
Francisco Pedraza III, Ajith KumarD, Jing Yong Ye, Dhiraj Sardar.
The University of Texas at San Antonio, San Antonio, TX.
This project focuses on exploring the near-infrared (NIR) optical and photoacoustic (PA) imaging capabilities of lanthanide-based nanoparticles to determine their potential use as multimodal imaging agents. Although several contrast agents are used for non-invasive NIR optical imaging, most are not capable of providing in-depth information with high signal-to-noise ratio. A way to circumvent this difficulty is to combine multiple imaging modalities. For example, NIR optical imaging is ideal for molecular and cellular imaging due to its tunability and selectivity; however, PA imaging has a superior spatial resolution and penetration depth to that of NIR optical imaging. If a single contrast agent is developed that functions with both imaging modalities, we could take advantage of the individual strengths, ultimately resulting in a more efficient multimodal imaging strategy. Lanthanide-based nanoparticles are perfect candidates for this application due to their excellent NIR spectral properties. By controlling the non-radiative processes through various emission channels, it is possible to generate strong PA signals that would help us explore the wavelength-dependent PA imaging features. For this project, nanoparticles were methodically designed, synthesized, and characterized. X-ray diffraction and electron microscopy were then used to identify the crystal structure and morphology along with spectroscopy for optical characterization. Next, a custom PA imaging system was utilized to record the acoustic signal following laser excitation of the nanoparticles. The results suggest that these lanthanide-based nanoparticles can serve as both optical and PA imaging agents. Further studies will examine their biocompatibility and comparison with current contrast agents.