Assessment of the Theranostic Potential of Gold Nanostars—A Multimodal Imaging and Photothermal Treatment Study

Abstract

Gold nanoparticles offer the possibility to combine both imaging and therapy of otherwise difficult to treat tumors. To validate and further improve their potential, we describe the use of gold nanostars that were functionalized with a polyethyleneglycol-maleimide coating for in vitro and in vivo photoacoustic imaging (PAI), computed tomography (CT), as well as photothermal therapy (PTT) of cancer cells and tumor masses, respectively. Nanostar shaped particles show a high absorption coefficient in the near infrared region and have a hydrodynamic size in biological medium around 100 nm, which allows optimal intra-tumoral retention. Using these nanostars for in vitro labeling of tumor cells, high intracellular nanostar concentrations could be achieved, resulting in high PAI and CT contrast and effective PTT. By injecting the nanostars intratumorally, high contrast could be generated in vivo using PAI and CT, which allowed successful multi-modal tumor imaging. PTT was successfully induced, resulting in tumor cell death and subsequent inhibition of tumor growth. Therefore, gold nanostars are versatile theranostic agents for tumor therapy.

Spiky Gold Nanoparticles for the Photothermal Eradication of Colon Cancer Cells

“…BGNPs pre-dispersed with 50% FBS were incubated with DLD1 cells for 24 h, and then the cellular uptake of the BGNPs was studied by flow cytometry. BGNPs are phototheranostic platforms [ 60 , 67 ] that allow both therapy (PTT) and label-free imaging. In fact, BGNPs can be used for optical imaging because of their capacity to absorb and scatter light in the visible and NIR regions.…”

Gold nanostar‐based complexes applied for cancer theranostics

“…Distinct from the conventional optical imaging in the millimeter range, PA imaging has been used to realize imaging depths of 5 cm in the NIR region 97‐99 . Due to the LSPR at a long wavelength around 1000–1200 nm and a high absorption versus scattering coefficient, AuNSs with multiple sharp branches are regarded as favorable agents for PA imaging 21,29,100 …”

Synthetic Antiferromagnetic Gold Nanoparticles as Bimodal Contrast Agents in MRI and CT—An Experimental In Vitro and In Vivo Study

“…Recently, major interest has been shown in hybrid nanostructures that integrate different material components to be used for multiple imaging techniques simultaneously, thereby overcoming the limitations of single modality nanoparticles and imaging. This has already led to the use of hybrid nanoparticles in dual-mode and multi-modal molecular imaging techniques, such as MRI and fluorescence imaging [ 15 , 16 ], MRI and PET [ 17 , 18 , 19 ], MRI and photoacoustic imaging [ 20 ], CT and photoacoustic imaging [ 21 ], MRI and CT [ 22 ] and more. Comparing the latter two techniques, on the one hand CT is advantageous with regard to its higher resolution and contrast generated between calcified tissue, air and soft tissue, but it exhibits poor soft-tissue contrast and relatively low sensitivity to contrast agents.…”