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ChemComm
DOI: 10.1039/C5CC05461C
Journal Name
COMMUNICATION
10ꢀ
2ꢀ
5ꢀ
1ꢀ
a)
a)
b)
DNA
DNA+PtEuL
15
10
5
0
1ꢀM
2ꢀM
2ꢀM
5ꢀM
5ꢀM
10ꢀM
10ꢀM
b)
-5
-10
-15
220 240 260 280 300 320
Wavelength(nm)
1ꢀM
c)
Fig. 3 a) CD spectra of plasmid DNA (20 nM in Tris-HCl buffer, pH = 7.4)
treated with or without PtEuL (50 ꢀM) in dark at 37oC for 12 h. b) Plasmid
DNA was incubated with the test compounds (20 μM) as indicated,
irradiated by UVA (light dose 50 J/m2), and then subjected to agarose gel
electrophoresis. The DNA gel images were obtained using GelRed Nucleic
Acid Stain (BIOTIUM).
Fig. 4 Two-photon (λex = 730 nm) induced images of HeLa cells incubated
with PtEuL at different dose concentrations (0, 1, 2, 5, 10 ꢀM) for 24 h. a)
without irradiation, b) after 30 min excitation, c) merged images of (a) and
(b).
In conclusion, we have designed and synthesized a platinum-
which indicates DNA nicking (single strand break) and linear
conformer, which indicates double strand break), is clearly seen.
Interestingly, strong DNA photocleavage activity is only seen with
PtEuL, but less significantly in cisplatin and not at all in EuL,
suggesting that a DNA damage mechanism distinct from that of
cisplatin is operating in PtEuL. The dark cytotoxicity of PtEuL was
evaluated in two cancer cell lines (HeLa and A549), together with
cisplatin. (Table 1. and Fig. S10) PtEuL is seen to exhibit a lower dark
cytotoxicity, compared to cisplatin, towards the HeLa and A549 cells,
with the respective IC50 of 22.5 ± 0.5 μM and 49.5 ± 0.1 μM. (Table
1) However, EuL showed no toxicity towards these two cancer cell
lines under identical conditions.
europium complex (PtEuL) which holds great promise as
a
controlled delivery vehicle of cisplatin. In addition, the Eu emission
produced upon the photo-dissociation of cisplatin from PtEuL
allows a real-time monitoring of the cisplatin release in vitro, thus
making it
a
luminescent imaging as well as antitumor
chemotherapeutic agent.
The work described in this paper was supported by grants from
the HKRGC (HKBU 203012) and HKBU (FRG1/14-15/015).
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