ABSTRACT
Prostate cancer (PCa) is one of the leading causes of death among men. Low-dose brachytherapy is an increasingly used treatment for PCa, which requires the implantation of tens of radioactive seeds. This treatment causes discomfort; these implants cannot be removed, and they generate image artifacts. In this study, the authors report on intratumoral injections of radioactive gold nanoparticles (Au NPs) as an alternative to seeds. The particles (103 Pd:Pd@Au-PEG and 103 Pd:Pd@198 Au:Au-PEG; 10-14 nm Pd@Au core, 36-48 nm hydrodynamic diameter) are synthesized by a one-pot process and characterized by electron microscopy. Administrated as low volume (2-4 µL) single doses (1.6-1.7 mCi), the particles are strongly retained in PCa xenograft tumors, impacting on their growth rate. After 4 weeks, a tumor volume inhibition of 56% and of 75%, compared to the controls, is observed for 103 Pd:Pd@Au-PEG NPs and 103 Pd:Pd@198 Au:Au-PEG NPs, respectively. Skin necrosis is observed with 198 Au; therefore, Au NPs labeled with 103 Pd only are a more advisable choice. Overall, this is the first study confirming the impact of 103 Pd@Au NPs on tumor growth. This new brachytherapy procedure could allow tunable doses of radioactivity, administered with smaller needles than with the current technologies, and leading to fewer image artifacts.
Subject(s)
Brachytherapy/methods , Gold , Nanoparticles , Palladium , Prostatic Neoplasms/radiotherapy , Animals , Cell Line, Tumor , Gold/chemistry , Gold/pharmacology , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Nanoparticles/chemistry , Nanoparticles/therapeutic use , Palladium/chemistry , Palladium/pharmacology , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Xenograft Model Antitumor AssaysABSTRACT
Pd nanoparticles (Pd NPs) were electrodeposited on the glassy carbon electrode (GCE). Then, Pd NPs/GCE was further inserted into H2 SO4 solution to polarize for 5 min to absorb a certain amount of active hydrogen. Then, the electrode was quickly inserted to HAuCl4 solution for 15 min. AuNPs were deposited spontaneously on the surface of Pd NPs due to the reduction of active hydrogen. As a result, Pd-AuNPs were modified on the surface of GCE. Next, aptamer I of thrombin was immobilized on Pd-Au nanoparticles. In the presence of thrombin, it bound with the aptamer immobilized on Pd-Au nanoparticles and thus the formed complex obstructed the catalysis of Pd-Au nanoparticles to H2 O2 . Hence, the reduction current of H2 O2 decreased with the increase of thrombin concentration. The aptamer sensor had a good linear relationship with the concentration of thrombin in the range of 2. 98-297 nmol/L with a detection limit of 0. 98 nmol/L.
