Plenary lecture of the XIII SBPMat (Brazilian MRS) meeting, given on September 29th 2014 by Prof. Luís Carlos Dias (Universidade de Aveiro, Portugal).

1. Physics Department & CICECO, Aveiro, Portugal
L. D. Carlos
29/09/2014

2. Carlos Brites Mengistie Debasu
Patricia Lima
Vitor Amaral Nuno Silva
João Rocha
Duarte Ananias
Rute Ferreira

3. Isabel
Pastoriza-
Santos
Angel Millán Fernando Palacio
Luiz Marzan
Paulo André
Instituto de
Telecomunicações

4. OUTLINE
I. Luminescent materials in bio & nanomedicine
I.1 Contrast agents & biomarkers
I.2 Nanoparticles for multimodal imaging and theranostic
II. Challenges for luminescence in bio & nanomedicine
II.1 NIR optical imaging (in vivo and in vitro)
II.2 Luminescent nanothermometers
III. Why nanothermometry? Which is need for?
IV. Ratiometric temperature sensing @ GFHybrids (Aveiro)
V. Joining heating and thermometry at the nanoscale
V.1 All-in-one optical heater-thermometer nanoplatform
(plasmonic-induced heating)
VI. Conclusions

5. I. Luminescent materials in nanomedicine
What is luminescence?
“Emission of light by certain
materials not resulting from
heat.”
Why light matters?
Central to linking cultural, economic and political aspects of the global society
…and God said, "Let there be light" (fiat lux), and there …was light!
The Book of Genesis

6. International Year of Light and Light-based Technologies
UN has recognized the importance of
raising global awareness about how light-based
technologies promote sustainable
development and provide solutions to
global challenges in energy, education,
agriculture & health.
Light plays a vital role in our daily lives and is an imperative cross-cutting discipline
of science in the 21st century
Medicine revolution;
XX century telecommunications revolution (laser, laser-diode, optical fiber,
Er3+-doped amplifier);
Infrastructure for the Internet
http://www.light2015.org/Home/About.html

7. Contrast agents and biomarkers
World market reaches more than one billion US dollar
MRI

8. NMR Imaging (MRI) Contrast Agents
Gd chelates, e.g. Gadodiamide, Omniscan
Change the relaxation times (T1, T2) of 1H in tissues and body
cavities where they are present
Without CA With CA
Defect of the blood-brain barrier after stroke
shown in MRI (T1-weighted images)

9. Biomarkers
Fluoroimmunoassay
Immunological method for clinical diagnosis. Relevant in prenatal and
neonatal screening tests, UV as well as to detect Energy transfer
proteins, viruses, antibodies,
tumor biomarkers and medicine residues.
Cisbio-US, Inc.
Long (ca. 10-3 s) 5D0 lifetime in the Eu3+ cryptate eliminates the fluorescence
interference from other compounds or any unbound XL665.
Concentrations of CD86 and CD28 species are quantify through the intensity of
the XL665 luminescence.

10. Nanoparticles for multimodal imaging and
theranostic
The vision: a multifunctional cargo platform
Imaging agents
Stimulus sensitive
agents
Specific targeting moiety
Biocompatible polymer
Drugs
Cell penetrating agents
M. Ferrari, Nature Rev. Cancer, 2005, 5, 161

11. Many examples for bimodal imaging, e.g. MRI & luminescence
Photos of cellular pellets
excited at 393 nm
Control (no NPs internalization)
Cell internalized ϒ-Fe2O3 NPs
negative contrast, T2-shortening
Fe2O3 NPs
Cell internalized
T1- & T2-weighted MRI
images of cellular pellets
SiO2@APS/DTPA:Eu,Gd NPs
positive contrast, r1=4.4 s-1mM-1
S. L. C. Pinho et al., Biomaterials, 2012, 33, 925; M. L. Debasu et al.,
Nanoscale, 2012, 4, 5154

12. Engineered design of theranostic UCNPs
Tri-modal imaging & targeted delivery of anticancer drugs
G. Tian et al., J. Mater. Chem. B, 2014, 2, 1379

13. II. Challenges for PL in nanomedicine
NIR optical imaging
NIR emitting dyes
Advantages
NIR photons penetrate deeper in
biological tissues, compared to visible light;
Tissues present less autofluorescence;
Better signal-to-noise discrimination;
Improved detection sensibility;
NIR photons interact less with biological
tissues, reducing the risk of disturbance or
damage.
In-vivo multispectral imaging systems
(spectral deconvolution filters excitation wavelengths,
390–770 nm, from a white-light source)
Mouse also imaged in X-ray mode.
http://acs.ufl.edu/?page_id=226

14. NIR-to-NIR down-shifting PL (1 photon excitation)
Core/shell NaGdF4:Nd3+/NaGdF4 NPs
PL images of HeLa cells incorporated the NPS (λex=740 nm)
G. Chen et al., Acc. Chem. Res., 2013, 46, 1474
In vivo whole body
imaging of a mouse
subcutaneously
injected with the
NPs
Depth penetration of light
Primary obstacle to applying in-vivo optical molecular imaging (OMI), light
cannot penetrate more than 5-6 cm into human tissue;
In-vivo OMI market will reaches $400 million in 2014

15. Luminescent thermometers

16. III. Why nanothermometry
Which is the need for?
J. Lee & N.A. Kotov, Nano Today, 2007, 2, 48; K.M. McCabe & M. Hernandez,
Pediatr. Res., 2010, 67, 469; D. Jaque & F. Vetrone, Nanoscale, 2012, 4, 4301;
J. Millen et al. Nature Nanotech., 2014, 9 425

17. Sensing temperature in
an accurate way with
sub–micron resolution
numerous features of
micro and nanoscale
electronic devices
(thermal transport, heat
dissipation, and profiles
of heat transfer)
critical for
understanding

18. Intracellular temperature distribution
Electron Microscope Photos of Brain Cancer
Cells(http://www.alternative-cancer.
net/Cell_photos.htm)
Increased metabolic activity: Higher T
than those of normal tissues
C.L. Wang et al., Cell. Res., 2011, 21, 1517; G. Kucsko et al., Nature,
2013, 500, 54; N. Inada & S. Uchiyama, Imaging Med., 2013, 5, 303

19. Temperature of living cells is
modified during every cellular
activity transfer rates as:
cell division
gene expression
enzyme reaction
changes in metabolic activity
Lung cancer cell division (SEM)
STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY
http://www.sciencephoto.com/set/1336

20. IV. Ratiometric temperature sensing
Unavailability of a nanothermometer with:
C.D.S. Brites et al., Nanoscale, 2012, 4, 4799

21. How it works?
Part of the energy level diagram for Ln3+ aquo ions Energy separation
between levels
comparable to the
thermal energy kBT
Impossible to
populate a single
energy level
Boltzmann
statistics: the
population will be re-distributed
among
energy levels with
similar energy

22. |1> is optically populated (from the ground state)
Due to the proximity of the |2> level (E), the initial |1>
population is thermally re-distributed among the two levels
The |2> population (N2) is (steady-state):
exp ( / ) 2 1 N N E k T B  
I1 & I2 are proportional to the corresponding populations:
N C I 
I2/I1 ratio:
C
2 E k T
exp ( / )
2
1
1
C
I
I
B  
ΔE
I2
I1
2
1
depends on geometrical factors and intrinsic properties of the
emitting level (e.g. branching ratios and quantum efficiency)

23. V. Joining heating and thermometry at
the nanoscale

24. Advantages relatively to the dual-particle
approach:
ACS Nano, 2014, 8 (5), 5199–5207

25. Uncontrolled spatial distribution of
nanoheaters and nanothermometers
Large distribution of the
nanoheater-nanothermometer
distances d
Average temperature of the sample
volume under irradiation (emission
intensity includes the contribution of
the nanothermometers that are away
from the nanoheaters);
Thermal sensing not achieved at the
same heating volume.
d
d
Heater-thermometer joint
venture at the nanoscale

26. M. L. Debasu et al., 25, 4868 (2013)
V.1 All-In-One
Optical Heater-
Thermometer
Nanoplatform
Assess the local temperature
of laser-excited Au
nanostructures using an all-in-one
nanoplatform comprising
(Gd,Yb,Er)2O3 nanorods
(thermometers) surface-decorated
with Au NPs (heaters).
Unambiguous attribution of
the white-light emission to an
incandescence process.

27. Heater-Thermometer Nanoplatforms
Synthesis
(Gd0.95Yb0.03Er0.02)2O3 NRs: simple wet-chemical route
M. L. Debasu et al., J. Phys. Chem. C, 2011, 115, 15297
Citrate stabilized spherical AuNPs: standard Turkevic method
J. Turkevich et al., Discuss. Faraday Soc., 1951, 11, 55

28. NRs-AuNPs-C
C (1.25-37.5) nominal Au amount (μmoles of the metal)
AuNPs immobilized on the NRs by the in situ reduction of HAuCl4
.3H2O using NaBH4
as a strong reducing agent in aqueous dispersion of the NRs.
The lower the amount of Au precursor, the fewer the number of AuNPs supported
on the NRs
Lower Au amount Higher Au amount
I. Pastoriza-Santos et al., Phys. Chem. Chem. Phys., 2004, 6, 5056

29. TEM IMAGES NRs-AuNPs
Crystallographic planes
and interplanar distances
for NRs (first image) and
AuNPs (second image)
The images on the right
side zoom in the regions
depicted by the white
circles on left.
C = 1.25
C = 2.5

30. C = 12.5
C = 25

31. UV-VIS-NIR Absorption
bare NRs
NRs-AuNPs-1.25
NRs-AuNPs-2.5
NRs-AuNPs-5.0
NRs-AuNPs-12.5
NRs-AuNPs-37.5
390 585 780 975 1170 1365
Normalized Absorbance
Wavelength /nm
Localized surface Au plasmon resonance, LSP (aqueous
dispersions of NRs-AuNPs-C)

32. Up-conversion emission spectra
ΔE≈ 760 cm-1
2H11/2
4S3/2
2F9/2
4I11/2
4I13/2
4I15/2
980 nm
ET
Er3+ Yb3+
2F5/2
2F7/2
Bare NRs (black lines) and NRs-AuNPs-1.25 (red lines) (600 W.cm-2
excitation with a 980 nm CW laser diode)

33. FIR =
I ( 2H11/2 ® 4I15/2 )
I ( 4S3/2 ® 4I15/2 )
=
gH AHwH
gSASwS
exp -
DE
kT
æ
è ç
ö
ø ÷
= Bexp -
DE
kT
æ
è ç
ö
ø ÷
ΔE(2H11/2-4S3/2)≈760 cm-1
limit of no laser
excitation (RT)

34. Evolution of FIR with pump power
NRs-AuNPs-2.5
NRs-AuNPs-1.25
bare NRs
NRs-AuNPs-5.0
100 200 300 400 500 600
4
3
2
1
FIR
Laser power density /Wcm-2
FIR plot of the 2H11/2→4I15/2 to 4S3/2→4I15/2 transitions vs. laser power
density for NRs-AuNPs-C, with C = 0 – 5.0.

35. FIR vs. absolute local temperature
Pump power density
32–600 W.cm-2 (1.25)
95–455W.cm-2 (2.5)
95–205 W.cm-2 (5.0)

36. 


relative sensitivit y
thermometeric parameter (FIR)
absolute sensitivit y

S
 

temperature








S
T
T S
S
a
a
Temperature sensitivity
Sensitivity of C=1.25 in the range of physiological interest!

37. What are the influence of exciting
the nanoplataform (through Yb3+) in
resonance with the Au surface
plasmon?
bare NRs
NRs-AuNPs-1.25
NRs-AuNPs-2.5
NRs-AuNPs-5.0
NRs-AuNPs-12.5
NRs-AuNPs-37.5
390 585 780 975 1170 1365
Normalized Absorbance
Wavelength /nm
How to do this?

38. STEM IMAGES NRs-AuNRs C = 3.05
Au NRs
Gd2O3:Er/Yb NRs
in preparation

39. UV-VIS-NIR Absorption
AuNRs-808nm
NRs@PSS@AuNRs-808nm-C=2.28
500 600 700 800 900
1.0
0.5
0.0
Normalized Absorbance
Wavelength /nm

40. 150 300 450 600
2.0
1.5
1.0
0.5
NRs-AuNPs-1.25
NRs@PSS@AuNRs-850nm-1.25
FIR
Laser power density /Wcm-2
AuNRs have strong heating
effect, compared to AuNPs,
resonance of the LSP band with
the laser beam wavelength.
Distinct dependence of FIR
(and temperature) with laser
power density (mechanism?)
360 420 480 540 600
2.0
1.5
1.0
0.5
NRs-AuNPs-1.25
NRs@PSS@AuNRs-850nm-1.25
FIR
Temperature /K

41. 41
VI. Messages to take home
Luminescent materials play a crucial role in the development of bio
and nanomedicine
NIR optical imaging may promote a revolution in the fluorescence
microscopy
Heater-thermometer nanoplatforms can improve the efficiency of
hyperthermia processes and are exciting tools to study heat transfer
processes at the nanoscale (probes to new phenomena?)

42. THERMOMETRY AT THE NANOSCALE
L. D. Carlos & F. Palacio, Eds.

43. ACKNOWLEDGEMENTS
FUNDAÇÃO PARA A CIÊNCIA E TECNOLOGIA
PEst-C/CTM/LA0011/2013; PTDC/CTM/101324/2008
EUROPEAN MULTIFUNCTIONAL MATERIALS
INSTITUTE
LUMINET— European Network on Luminescent Materials,
FP7-PEOPLE-2012-ITN (316906)
COST ACTION MP1202
PVE Grant 313778/2013-2, Science without borders
Spatial averaging > 1.5×103 μm