Gold Nanorods (GNRs) are attractive as contrast agents for photothermal (PT) ablation [1] and for photoacoustic (PA) imaging of cancer [2,3], due to their high optical absorbance in the near-infrared (NIR) range, their chemical versatility and their potential to home into tumors. To date, one of the most common approaches to deliver GNRs into tumors is their direct injection into the bloodstream [4]. However, this pathway remains problematic, because most of the particles are captured by the immune system and their optical behavior undergoes modifications in the body. One alternative may be the use of cellular vehicles that exploit the tropism of tumor-associated macrophages (TAM) [5]. In essence, one may think to harvest these macrophages from a patient, load them with GNRs in vitro, inject them back into the patient and rely on their innate ability to migrate to the tumor and deliver the particles as a Trojan horse [5]. In order to exploit the potential of these plasmonic cellular vehicles, it is of fundamental importance to understand the influence of the biological system on the GNRs, including their photostability and efficiency of PT and PA conversion. It is known that when GNRs are irradiated with a laser in resonance with their longitudinal plasmon oscillations, their overheating triggers processes of reshaping or fragmentation, which result into dramatic optical modifications [6-8]. These issues may become more relevant when GNRs are internalized by cells, since their accumulation into intracellular vesicles may exacerbate their overheating. In this contribution, we investigate how the cellular uptake affects the optical properties of GNRs taken up by macrophages. Both PEGylated GNRs with a cationic profile and J774a.1 macrophages loaded with these particles were dispersed into biopolymeric phantoms and directed to a home-made setup for PA and PT analysis. We compare their photostability and efficiency of PA and PT conversion under NIR pulsed and continuous wave irradiation at different laser fluences and find insignificant modifications. We expect that these results will be of importance for many biomedical applications involving plasmonic particles, such as photoacoustic imaging and photothermal ablation.
FEASIBILITY OF PLASMONIC CELLULAR VEHICLES FOR PHOTOACOUSTIC IMAGING AND PHOTOTHERMAL THERAPY OF CANCER
M de Angelis;R Pini
2015
Abstract
Gold Nanorods (GNRs) are attractive as contrast agents for photothermal (PT) ablation [1] and for photoacoustic (PA) imaging of cancer [2,3], due to their high optical absorbance in the near-infrared (NIR) range, their chemical versatility and their potential to home into tumors. To date, one of the most common approaches to deliver GNRs into tumors is their direct injection into the bloodstream [4]. However, this pathway remains problematic, because most of the particles are captured by the immune system and their optical behavior undergoes modifications in the body. One alternative may be the use of cellular vehicles that exploit the tropism of tumor-associated macrophages (TAM) [5]. In essence, one may think to harvest these macrophages from a patient, load them with GNRs in vitro, inject them back into the patient and rely on their innate ability to migrate to the tumor and deliver the particles as a Trojan horse [5]. In order to exploit the potential of these plasmonic cellular vehicles, it is of fundamental importance to understand the influence of the biological system on the GNRs, including their photostability and efficiency of PT and PA conversion. It is known that when GNRs are irradiated with a laser in resonance with their longitudinal plasmon oscillations, their overheating triggers processes of reshaping or fragmentation, which result into dramatic optical modifications [6-8]. These issues may become more relevant when GNRs are internalized by cells, since their accumulation into intracellular vesicles may exacerbate their overheating. In this contribution, we investigate how the cellular uptake affects the optical properties of GNRs taken up by macrophages. Both PEGylated GNRs with a cationic profile and J774a.1 macrophages loaded with these particles were dispersed into biopolymeric phantoms and directed to a home-made setup for PA and PT analysis. We compare their photostability and efficiency of PA and PT conversion under NIR pulsed and continuous wave irradiation at different laser fluences and find insignificant modifications. We expect that these results will be of importance for many biomedical applications involving plasmonic particles, such as photoacoustic imaging and photothermal ablation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
