Chemistry Reference
In-Depth Information
Figure 5.15
(a)
T1-weighted magnetic resonance images of UCNPs with
edge lengths of 20 nm and 41 nm at various concentrations in
water. (b)
T
1
T1-weighted magnetic resonance images of SK-BR-3
cells (1.3*10
7
cells) incubated with 20 nm UCNPs at various
concentrations for 24 h; cellular uptake of 20 nm UCNPs in
SK-BR-3 cells. (c1, d1, e1, f1) Bright field images. (c2, d2, e2,
f2) Luminescence images with the excitation at 980 nm and
the detection at 400-700 nm. Cells were incubated with the
UCNPs with 100 mg mL
−1
of Gd
3+
concentration at 37.8
T
1
. (c)
Cells incubated without UCNPs, showing no autofluorescence.
Incubation time was (d) 30 min, (e) 2 h, (f ) 4 h [77].
2
Though lanthanide-fluoride bimodal nanocrystals are
considered promising in combined optical imaging and MRI, most
investigations were undertaken
in vitro
. Zhou
et al
. presented
bimodal
in vivo
animals imaging using a Tm
3+
/Er
3+
/Yb
3+
co-doped
3+
ions at
or near the surface of the nanocrystals were the primary contributor
to relaxivities. Thus they selected NaGdF
NaGdF
nanoparticles [78]. Their studies revealed that Gd
4
as host which produced
4
3+
ions. Figure
5.16 shows that upconversion luminescence signal was observed 40
min after intravenous injection.
better MRI contrast than NaYF
host doped with Gd
4
Ex-vivo
imaging suggested that the
