Peparation Of Mutifunctional Magnetic Fe₃O₄ Complex Fluorescencent Photosensitizer And It's PDT Anti-cancer Activity

Photodynamic therapy?PDT?,as a noninvasive therapeutic modality providing painless and repeating treatment for patients,has been entering the mainstream of the cancer treatments recently.Pyropheophorbide-a?PPa?,as a degradation product of chlorophyll-a,has been shown to be a potent photosensitizer in PDT.In this academic paper,PPa was used as a raw material,on the one hand,13¹-ortho-trifluoromethyl-phenylhydrazone-pyropheophorbide-a?PHPa?was synthesiz-ed by conjugating phenylhydrazone on the C-13¹ position of Pa that increasing the?-conjugation extending from the porphyrin core.It not only showed a greater molar extinction coefficient reached 4.55×10⁴ L mol^-1cm^-1,the long absorption wavelength?681 nm?as we expected that makes it potential in deep tumor treatment,but also showed higher single oxygen quantum yield??_?=40.5%?in DMF solutions.On the other hand,in order to solve the problem that PPa is prone to aggregation under physiological conditions because of the?-?conjugation between the chlorine core,photosensitizer pyropheophorbide-a?PPa?was covalently anchored on the surface of core–shell Fe₃O₄@SiO₂@APTES nanoparticles full of functional amino groups by a bridging glutaryl group,thus obtaining multifunctional magnetofluorescence nanoparticles Fe₃O₄@Si O₂@APTES@Glutaryl-PPa?MFNPs?for PDT.The results showed that the MFNPs have good dispersibility in alcohol and water,strong superparamagnetic and good photoluminescence property.Meanwhile,in order to improve the activity of Pa for particular clinical application,novel chlorin photosensitizer PPa coated multifunctional magneto-fluorescent nanoparticles Fe₃O₄@SiO₂@CS@PPA?MFCSPPA?were strategically designed and prepared for PDT based on the good solubility and magnetic targeting of Fe₃O₄@SiO₂ nanoparticles,excellent biocompatibility and biodegradability of chitosan?CS?polymer,and the unique fluorescence and photodynamic activity of PPa.We investigated the ultraviolet-visible spectra,fluorescence emission spectra of PHPa?MFNPs?MFCSPPA,together with the in vitro photodynamic therapy against human He La cervical cancer cell line,respectively.Firstly,the nucleus was stained with DAPI,and cell imaging was performed with a fluorescence inverted microscope.The results indicated that all of them could be successfully taken up by He La cells,andmeanwhile displayed intense homogeneous red fluorescence in the cytoplasm around the nucleus.Secondly,AO?acridine orange?/EB?ethidium bromide?double fluorescent staining,a label of the nuclear DNA,were utilized to evaluate the changes of nucleus after PDT treatment.The results showed that they could result in damage under light and apoptotic cell death in He La cells.Moreover,the mechanism of photochemical processes was investigated by using separately quenching agent sodium azide?SA?and Dmannitol?DM?,which have relative specificity for ¹O₂ and hydroxyl radicals.The results demonstrated that all of them could induce the occurrence of Type ? and Type ? photodynamic reactions,which could occur simultaneously in photosensitizer mediated process,and their relative contributions depend on the type of photosensitizer.