<p>Nanoparticles (NPs) exhibiting X-ray-excited UV-C luminescence can be used in radiation therapy to deactivate cancer cells through photochemical reactions of DNA with UV-C quanta. Colloidal solutions of monoclinic La<sub>1−x</sub>Pr<sub>x</sub>PO<sub>4</sub> NPs (<i>x</i> = 0.01–0.3), luminescent in the UV-C range (220–280&#xa0;nm), with different morphologies, from nanofiber (diameter and length not larger than 15 and 600&#xa0;nm, respectively) to short nanorod (diameter and length not larger than 8 and 35&#xa0;nm, respectively), were obtained by a microwave-assisted hydrothermal method. For possible biomedical use, the synthesis parameters (pH = 8, anion excess coefficient = 2) were determined, at which nanorods of suitable sizes (diameter and length not larger than 10 and 80&#xa0;nm, respectively) with the brightest UV-C luminescence among all synthesized nanorods were obtained. A gradual increase in the optimal concentration of Pr<sup>3+</sup> ions with maximum luminescence brightness from 4&#xa0;mol-% for nanofibers to 6&#xa0;mol-% for short nanorods was established. The shift of the intensity ratio of UV-C transitions toward the long-wave 4f<sup>1</sup>5d<sup>1</sup>→<sup>3</sup>H<sub>6</sub> transition was shown for nanofibers, whereas for nanorods all 4f<sup>1</sup>5d<sup>1</sup>→<sup>3</sup>H<sub>4,5,6</sub> transition intensities were approximately equal. A new laser ultramicroscopy method based on the detection of elastically scattered light with subsequent nanoparticle tracking analysis was used to calculate the hydrodynamic radii and to monitor the colloidal behavior of NPs in pH-modified aqueous media. The highest sedimentation and aggregation stability of NPs was found in an acidic medium (pH = 4), and temporary stability was also found in alkaline media (pH = 8, 10).</p>

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Aqueous solutions of La1−xPrxPO4 nanoparticles: microwave-assisted hydrothermal synthesis, X-ray excited UV-C luminescence, and colloidal properties

  • Artem Shaidulin,
  • Elena Orlovskaya,
  • Alexandr Popov,
  • Sergey Batygov,
  • Liudmila Iskhakova,
  • Oleg Uvarov,
  • Gleb Silaev,
  • Sergei Klimin,
  • Mikhail Danilkin,
  • Kirill Boldyrev,
  • Yuri Vainer,
  • Vladimir Makhov

摘要

Nanoparticles (NPs) exhibiting X-ray-excited UV-C luminescence can be used in radiation therapy to deactivate cancer cells through photochemical reactions of DNA with UV-C quanta. Colloidal solutions of monoclinic La1−xPrxPO4 NPs (x = 0.01–0.3), luminescent in the UV-C range (220–280 nm), with different morphologies, from nanofiber (diameter and length not larger than 15 and 600 nm, respectively) to short nanorod (diameter and length not larger than 8 and 35 nm, respectively), were obtained by a microwave-assisted hydrothermal method. For possible biomedical use, the synthesis parameters (pH = 8, anion excess coefficient = 2) were determined, at which nanorods of suitable sizes (diameter and length not larger than 10 and 80 nm, respectively) with the brightest UV-C luminescence among all synthesized nanorods were obtained. A gradual increase in the optimal concentration of Pr3+ ions with maximum luminescence brightness from 4 mol-% for nanofibers to 6 mol-% for short nanorods was established. The shift of the intensity ratio of UV-C transitions toward the long-wave 4f15d13H6 transition was shown for nanofibers, whereas for nanorods all 4f15d13H4,5,6 transition intensities were approximately equal. A new laser ultramicroscopy method based on the detection of elastically scattered light with subsequent nanoparticle tracking analysis was used to calculate the hydrodynamic radii and to monitor the colloidal behavior of NPs in pH-modified aqueous media. The highest sedimentation and aggregation stability of NPs was found in an acidic medium (pH = 4), and temporary stability was also found in alkaline media (pH = 8, 10).