Application Of Metal-organic Framework Nanostructures In Photodynamic/drug Combination Therapy

In recent years,photodynamic therapy(PDT)has become one of the most important cancer treatments.Under a specific light irradiation,PDT can utilize photosensitizers to convert the oxygen into singlet oxygen,resulting in the death of cancer cells.Compared with the traditional tumor treatments,PDT has the advantages of non-invasiveness,high spatio-temporal controllability,and low drug resistance.However,the commonly used photosensitizers have many problems such as the hydrophobicity,high aggregaterate,low intracellular residence,and hand for modifications,thereby leading to a very limited bioapplications.In order to improve the therapeutic result of PDT,the following studies were carried out:(1)The porphyrin metal organic frameworks of PCN-224 with a uniform morphology and particle size have been successfully synthesized.The as-synthesized PCN-224(labeled as PCN)can be used as high efficient photosensitizers for PDT.Also,the PCN with a high chemical stability can effectively avoid the leakage or decomposition of the photosensitizer during the therapy,thereby improving the PDT effect of cancer treatment.(2)A new kind of core-shell structured metal-organic frameworks PCN@DOX/ZIF has been prepared by coating a uniform shell of DOX/ZIF-8 on the surface of PCN.The resulted PCN@DOX/ZIF can be simultaneously used for light-triggered PDT and pH-triggered chemocherapy.Typically,PCN core can generate singlet oxygen under 640 nm near-infrared light for PDT,while the anticancer drug of DOX in the ZIF-8 shell can be successfully released at low pH,achieving a pH-sensitive chemocherapy.(3)At the cellular level,we used the laser confocal experiments to prove that PCN@DOX/ZIF can be successfully taken up by the cancer cell,and then release the DOX gradually.The result of MTT indicated that PCN@ZIF has a good biocompatibility.Under 640 nm light irradiation,PCN@DOX/ZIF can achieve a synergistic photodynamic/drug cancer treatment.