1. J. Wanga, H. Yan Tangb, W. Li Yangb and J. Yao Chen*a
Aluminum phthalocyanine and gold nanorod conjugates: the combination of photodynamic therapy and photothermal therapy to kill cancer cells
J. Wanga, H. Yan Tangb, W. Li Yangb and J. Yao Chen*a
ABSTRACT: AlPcSs, popularly used photosensitizers, were linked on the surfaces of AuNRs by the electrostatic binding to form AlPcS-AuNRs conjugates, in order to improve the photo-therapy efficiency of cancer cells by combining the PDT of AlPcSs and the PTT of AuNRs. The AlPcS’s fluorescence is two-fold enhanced when they adhered on the surfaces of AuNRs probably due to the surface Plasmon coupling, which would facilitate the AlPcS detection. The fluorescence images show that AuNRs can carry loaded AlPcSs to penetrate into human nasopharyngeal carcinoma cells with a fast speed, achieving the effective intracellular delivery of AlPcSs. The PTT effect of cellular AuNRs alone under the white light irradiation of 50 minutes decreased the cell viability to 77%, and the PDT effect of cellular AlPcS-AuNRs with filtered red light ( nm) irradiation of 50 minutes lowered the cell viability to 79%. However, with the same white light irradiation of 50 minutes, the AlPcS-AuNRs destroyed most cells leaving the cell viability to 28%, reflecting a typical synergistic effect on cell killing. These results suggest that the combination of PTT and PDT with AlPcS-AuNRs is a promising strategy for improving the phototherapy of cancers.
RESULTS and DISSCUSION
Fig. 2. (a) Molecular structure of AlPcS. (b) The absorbance and emission spectra of AlPcSs
Fig. 1. (a) TEM image of AuNRs (b) The extinction spectrum of AuNRs
Fig. 3. (a) Fluorescence emission spectra at the excitation of 405 nm. (b) Excitation fluorescence spectra at the emission of 680 nm. (c) The differential spectrum (d) Fluorescence emission spectra at the excitation of 520 nm.
Fig. 5. (a) Fluorescence intensity decreasing of DPBF in AlPcS-AuNRs (b) The comparison of DPBF (3 μM) photo-degradations between the AlPcS-AuNRs (0.05 nM), AlPcSs (5 μM) and AuNRs (0.05 nM) aqueous solutions under the irradiation of the broad region light (12 mW).
Fig. 6. Viability of KB cells incubated with free AlPcS or AlPcS-AuNRs for 40min, followed by irradiations with different light doses, measured by MTT assay. The irradiation power density of broad region light is 20 mW/cm2, and that of red light ( nm) filtered from the broad region light is 2.7 mW/cm2.
Fig. 4. Confocal images of uptake of AlPcSs and AlPcS-AuNRs by KB cells: (a) AlPcSs fluorescence images(b) AlPcS-AuNRs fluorescence images (c) AlPcS-AuNRs reflectance images in the same cells as those in b. Left: fluorescence images; center: DIC images; and right: merged images. The bar is 20 µm.
CONCLUSION:The AlPcSs easily bind on the surfaces of AuNRs to form the conjugates by electrostatic force. The AuNRs can carry the loaded AlPcSs to penetrate into cells with a fast speed, achieving the cellular delivery of AlPcSs. The surface plasmon resonance of AuNRs enhances the fluorescence of adhered AlPcSs and induces the UV soret absorption band of AlPcSs to red-shift to the visible region, which facilitates the AlPcS detection. The AlPcS-AuNRs can combine the PDT and PTT effects to synergistically kill cancer cells with a broad region light irradiation. Therefore, the strategy of AlPcS-AuNRs is a promising way, and worth investigating further to improve the cancer therapy.
REFERENCES :
1.Link S and El-Sayed MA. Int. Rev. Phys. Chem. 2000; 19:
2. Genevieve M, Vieu C, Carles R, Zwick A, Briere G, Salome L and Trevisiol E. Microelectron. Eng. 2007; 84:
3. Cheng Y, Samia AC, Meyers JD, Panagopoulos I, Fei B and Burda C. J. Am. Chem. Soc. 2008; 130: 10643–10647.
4. Kou XS, Zhang SZ, Yang Z, Tsung CK, Stucky GD and Yan CHJ. Am. Chem. Soc. 2007; 129: 6402–6404.
5. Ni WH, Kou XS, Yang Z and Wang JF. ACS Nano 2008; 2: 677–686.