The invention provides a novel approach to hyperthermia 5 for cancer treatment
based on multiphonon relaxation of optical excitation in rare-earth (particularly
Dy3+) doped nanocrystals after laser irradiation that allows fast and accurate
local heating to a preset temperature.
A collection of nanoparticles suitable for use in hyperthermia treatment of
10 cancerous and non-cancerous cells by laser irradiation in the wavelength of
the transparency window of biological tissue (800nm – 1300 nm) preferably
800 – 900 nm is provided, wherein each nanoparticle comprises a crystalline
host structure, and at least one species of rare-earth dopant ion.
The at least one species of rare-earth dopant ion may be Dy3+, Sm3+, Eu3+,
15 Tb3+, Ho3+, Tm3+, Pr3+, Nd3+, and Er3+ ions.
The crystalline host structure may be a dielectric such as a phosphate, a
vanadate, a molibdate, a tungstate, an oxide or a fluoride, or a semiconductor
The heating effect is observed at low dopant concentrations, for example the
20 concentration of the at least one species of dopant may be in the range to 5 to
100 molar %. However, the heating effect is proportional to the dopant
concentration, therefore the higher the dopant concentrations the higher the
change in temperature of the nanoparticles upon irradiation, therefore the
dopant concentration is preferably in the range 80 to 100 molar %, more
25 preferably in the range 90 to 100 molar % or still more preferably 95.0 to
100.0 molar %.