Nanotechnology Used In Photodynamic Therapy Of Tumor

The sulfonated aluminium phthalocyanines (AlPcSs), commonly used photosensitizers (PSs) for photodynamic therapy of cancers (PDT), were conjugated to amine-dihydrolipoic acid coated quantum dots (QDs) by the electrostatic binding with the linkage of about 70 AlPcSs per QD. The AlPcS-QD conjugates can utilize the high light absorption coefficients of QDs to indirectly excite AlPcSs producing singlet oxygen via fluorescence resonance energy transfer (FRET), suggesting a new excitation model for PDT. The AlPcS-QD conjugates easily penetrated into KB cancer cells and performed the FRET with the efficiency of about 80% in cells. Under the irradiation of a 532 nm laser, which is at the absorption region of QDs but not fitted to the absorption band of AlPcSs, the cellular AlPcS-QD conjugates can destroy the most cancer cells via FRET mediated PDT, demonstrating the potential of this new strategy.Hexadecyl trimethyl ammonium bromide coated gold nanorods (AuNRs) with positive charges were effectively bound to negatively charged suifonated aluminium phthalocyanine (AlPcS), a photosensitizer for photodynamic detection and therapy, due to the electrostatic force, with a loading content of 104 AlPcS molecules per rod. A five-fold increase in the AlPcS fluorescence of the AlPcS-AuNRs complex was seen. The excitation fluorescence spectrum of the AlPcS-AuNRs with a typical 520 nm band fits well with the resonance band of AuNR surface plasmons, suggesting that such increased AlPcS fluorescence is produced from the strong surface plasmons of AuNRs. The intracellular distribution of AlPcS-AuNRs was studied in the QGY liver cancer cells by respectively imaging the AlPcS fluorescence and AuNRs reflectance with a confocal microscope. Furthermore, the AlPcS-AuNRs-loaded cells were photodynamically damaged after being exposed to red light in a light-dose dependent manner. In contrast, no phototoxicity of the cells was seen after incubation with the same amount of free AlPcS, indicating that the AlPcS-AuNRs can enhance the AlPcS-mediated photodynamic effect. In addition, the loaded AlPcS can be photothermally released from AuNRs in the cells by the irradiation of an 800 nm femto-second laser, demonstrating the potential for a controlled drug release.