Controlled size and morphology of EDTMP-doped hydroxyapatite nanoparticles as model for 153Samarium-EDTMP doping

Abstract

Hydroxyapatite (HA) nanoparticles have been studied as nano-sized carriers for the delivery of therapeutic agents. One important consideration for these carriers to be used effectively is their bio-distribution in vivo, of which particle size has a significant effect. In this work, HA nanoparticles doped with Ethylene-diamine-tetramethylene-phosphonate (EDTMP) were synthesized via co-precipitation as a model for HA doped with (153)Samarium ((153)Sm) EDTMP. EDTMP has high affinity for radioactive (153)Sm isotopes that can emit both gamma and beta radiation. The effects of synthesis temperature, amount of dopant and hydrothermal treatment on the size of HA-EDTMP nanoparticles were therefore studied. The results showed that the EDTMP ligand was successfully incorporated in the nanoparticles without changing the crystal structure as shown from X-ray diffractometer (XRD) analysis. From the Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) micrographs, it was observed that shorter rod-like nanoparticles, obtained at low synthesis temperatures, became elongated needle-like nanoparticles with increasing temperature. Increasing dopant amount by five fold increases particle size slightly, while a two fold increase in dopant amount has no significant effect. Hydrothermal treatment increases particle crystallinity and results in smooth elongated rod-like structures. The size of HA nanoparticles doped with EDTMP can therefore be manipulated by controlling synthesis temperature and through hydrothermal treatment.

Chelating agents for radiolanthanides: Applications to imaging and therapy

“…However, complexes of the other isotopes were formed directly in the chromatography elution in an effort to minimize loss of activity. The work demonstrated the potential of α and β therapy by 149 Tb and 161 Tb, as well as the PET and SPECT imaging capability of 152 Tb, 155 Tb and 161 Tb. It was proposed that this quartet of isotopes offers potential users chemically/biologically identical species for multiple applications.…”

“…The process was found to be quantitative. 16 149 Tb, 152 Tb, 155 Tb, 160 keV. The generator has been used for analytical applications, 20 but has yet to find applications as a therapeutic agent, and coordination complexes of 172 Lu have not yet been reported.…”

“…In plasma, the 161 Tb-DOTATATE complex showed the same stability as the 177 Lu analogue. Also reported, is the use of 155 Tb in the formation of complexes of DOTATATE. SPECT imaging was utilised for preclinical evaluation.…”

“…138 155 Tb complexes of DOTA-MD (minigastrin analogue: peptide sequence, HLeu-Glu-Glu-Glu-Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH), chCE7 (a glycosylated monoclonal anti-L1-CAM antibody) and cm09 (albumin binding entity) derivatives have been evaluated for SPECT imaging in tumour-bearing mice. The chCE7 sequence was conjugated with CHX-A"-DTPA, but no details were given of the method of conjugation for the minigastrin in the 155 Tb-DOTA-MD complex. The long physical halflife of 155 Tb was found to be a good match to the long biological half-lives of the complexes.…”

“…The chCE7 sequence was conjugated with CHX-A"-DTPA, but no details were given of the method of conjugation for the minigastrin in the 155 Tb-DOTA-MD complex. The long physical halflife of 155 Tb was found to be a good match to the long biological half-lives of the complexes. The corresponding 177 Lu-DOTA-chCE7 139 and 177 Lu-DOTA-cm09 140 species are also known, the latter being the first folic acid targeted radiolanthanide.…”