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Nd-doped Upconverting Nanoparticles for Deep Tissue Imaging

Söderlund, Hugo LU (2014) PHYM01 20132
Department of Physics
Atomic Physics
Abstract
During the last decade, upconverting nanoparticles (UCNPs)
doped with rare-earth (RE) ions have been extensively studied in
the field of biophotonics. Due to their unique properties of anti-
Stokes shifted luminescence and with excitation and emission wavelengths
optimal for biomedical imaging, they have become an interesting
class of fluorescent contrast agents. An issue with downconverting
fluorescent contrast agents for imaging in tissue is the
inevitable autofluorescence that overlaps the signal from the added
fluorophore, limiting the signal-to-background ratio. With UCNPs
it is possible to achieve a near autofluorescence free signal due to
their upconverting nature.
Up to date, one of the most efficient UCNPs is the Yb/Tm
... (More)
During the last decade, upconverting nanoparticles (UCNPs)
doped with rare-earth (RE) ions have been extensively studied in
the field of biophotonics. Due to their unique properties of anti-
Stokes shifted luminescence and with excitation and emission wavelengths
optimal for biomedical imaging, they have become an interesting
class of fluorescent contrast agents. An issue with downconverting
fluorescent contrast agents for imaging in tissue is the
inevitable autofluorescence that overlaps the signal from the added
fluorophore, limiting the signal-to-background ratio. With UCNPs
it is possible to achieve a near autofluorescence free signal due to
their upconverting nature.
Up to date, one of the most efficient UCNPs is the Yb/Tm
NaYF4 UCNPs. With an excitation wavelength of 975 nm and
emission at 800 nm they operate in the diagnostics window (600
- 1200 nm), allowing for substantial tissue penetration. Unfortunately,
water has an absorption peak at 975 nm, leading to a loss
in penetration depth as well as heat produced in the tissue. Very
recently, Nd/Yb co-sensitized UCNPs have been synthesized,
tuning the excitation wavelength to 808 nm. With a lower water
absorption at 808 nm the new co-sensitized UCNPs are proposed
to gain in penetration depth as well as reduce heat production in
tissue. This thesis explores the advantages of using the newly proposed
UCNPs as compared to Yb/Tm UCNPs. By using tissue
phantoms with realistic optical properties, the penetration depth as
well as the signal loss was evaluated experimentally. Additionally,
simulations were performed in order to further explore the benefits
of the new particles. Based on the results presented in this work,
the new UCNPs may very well replace the traditional particles for
certain applications, and may lead us one step closer to finding the
optimal tools for biomedical applications. (Less)
Please use this url to cite or link to this publication:
author
Söderlund, Hugo LU
supervisor
organization
course
PHYM01 20132
year
type
H2 - Master's Degree (Two Years)
subject
keywords
fluorescence imaging, Upconverting nanoparticles, biophotonics, Nd-doped comparison
report number
LRAP-490
language
English
id
4497295
date added to LUP
2014-10-20 14:12:07
date last changed
2015-06-02 09:57:13
@misc{4497295,
  abstract     = {During the last decade, upconverting nanoparticles (UCNPs)
doped with rare-earth (RE) ions have been extensively studied in
the field of biophotonics. Due to their unique properties of anti-
Stokes shifted luminescence and with excitation and emission wavelengths
optimal for biomedical imaging, they have become an interesting
class of fluorescent contrast agents. An issue with downconverting
fluorescent contrast agents for imaging in tissue is the
inevitable autofluorescence that overlaps the signal from the added
fluorophore, limiting the signal-to-background ratio. With UCNPs
it is possible to achieve a near autofluorescence free signal due to
their upconverting nature.
Up to date, one of the most efficient UCNPs is the Yb/Tm
NaYF4 UCNPs. With an excitation wavelength of 975 nm and
emission at 800 nm they operate in the diagnostics window (600
- 1200 nm), allowing for substantial tissue penetration. Unfortunately,
water has an absorption peak at 975 nm, leading to a loss
in penetration depth as well as heat produced in the tissue. Very
recently, Nd/Yb co-sensitized UCNPs have been synthesized,
tuning the excitation wavelength to 808 nm. With a lower water
absorption at 808 nm the new co-sensitized UCNPs are proposed
to gain in penetration depth as well as reduce heat production in
tissue. This thesis explores the advantages of using the newly proposed
UCNPs as compared to Yb/Tm UCNPs. By using tissue
phantoms with realistic optical properties, the penetration depth as
well as the signal loss was evaluated experimentally. Additionally,
simulations were performed in order to further explore the benefits
of the new particles. Based on the results presented in this work,
the new UCNPs may very well replace the traditional particles for
certain applications, and may lead us one step closer to finding the
optimal tools for biomedical applications.},
  author       = {Söderlund, Hugo},
  keyword      = {fluorescence imaging,Upconverting nanoparticles,biophotonics,Nd-doped comparison},
  language     = {eng},
  note         = {Student Paper},
  title        = {Nd-doped Upconverting Nanoparticles for Deep Tissue Imaging},
  year         = {2014},
}