Gold nanocage-photosensitizer conjugates for dual-modal image-guided enhanced photodynamic therapy

by Chen, Jingyi; Jenkins, Samir V.; Srivatsan, Avinash; Jeon, Mansik; Kim, Chulhong; Pandey, Ravindra K.


The gold nanocage-photosensitizer conjugate is developed by noncovalently encapsulating a photosensitizer in the poly(ethylene glycol) (PEG) coated gold nanocages (AuNCs) as a promising nanomedicine for cancer theranostics. The hydrophobic photosensitizer, 3-devinyl-3-(1'-hexyloxyethyl)pyropheophorbide (HPPH), is used in these studies. The stability of the conjugates are examd. in different media. It has been found that the conjugate is stable in saline solns., while incubation in protein rich solns. leads to gradual unloading of the HPPH. The release of HPPH is monitored optically by fluorescence and photoacoustic imaging. The slow nature of the release in turn leads to an increase in accumulation of the drug within implanted tumors. The conjugate is found to generate more therapeutic singlet oxygen and have a lower IC50 value than the free drug alone, and thus show a significantly suppress the tumor growth as compared to the free drug.