Study On The Interaction Of Phthalocyanine With Proteins And Preparation Of The Conjugates

Photodynamic Therapy (PDT) is a new and developing technique for therapy of cancer, the photosensitizer(PS) is one of significant factor in PDT. The more advantages of phthalocyanine in PDT had been demonstrated. Nowadays, how to enhance the selective uptake of PS by targeted tumor is one of significant fields. One of the most efficient routes is binding some targeting carriers with PS, and directing cancer cells. Serum albumin and apo-transferrin have been proved to be efficient delivery carries. In this text, on the basis of preceding work, the interaction on the phthalocyanine with proteins and preparation some conjugates were studied. It is hoping to offer some interesting information on designing new targeting photosensitizer compounds. The main results are summarized as following. 1) Studied the interaction on phthalocyanine with proteins by spectral analysis methods. We have been studied the influence of proteins'effect on phthalocyanine's UV spectra and states in Tris-HCl, analyzed the effects of phthalocyanine on proteins'structure, calculated the binding constants and sites. The studied phthalocyanines include 14 peripheral-substituded phthalocyanines such as ZnPcCOOR8,ZnPcCOOH8,ZnPcCOOH16,ZnPc(COOH)4,ZnPc(COOH)8 and 15 axis-substituded phthalocyanines such as Si3,Si4,Si10,Si11.The studied proteins include BSA,HSA,mBSA and apoTf. Moreover, we pilotly summarized the effects of structure on interaction: the center ion of phthalocyanine, the number and place of groups, the difference of peripheral-substituted and axis-substituted phthalocyanines, axis-substituted symmetrically and unsymmetrically, the effects of charges distributing et.al. 2) The conjugates were also prepared by incubating a mixture of phthalocyanine and the corresponding serum albumin followed by separation by gel permeation chromatography. The molar ratio of conjugates were gained by spectra method and CBB methods. The conjugates included ZnPcCOOR8-BSA ,ZnPcCOOR8-HSA ,ZnPcCOOH8-BSA,ZnPcCOOH8-HSA,ZnPcCOOH16-BSA et.al. The UV spectra and fluorescence spectra and quanta yield of phthalocyanine were compared with conjugates. Comparing with phthalocyanine, the conjugates have more stronger intensity at the specific peak and have red shift, and have higher quanta yield. 3) The in vitro experiment compared the PDT activity of Si3,JSB,C3,C3+,C4 and their conjugates to BSA and apoTf on MCF-7 and the PDT activity of Si3 and Si3-BSA on HepG2. The results show conjugates have more PDT activity than phthalocyanine. For example, Si3-BSA(1:1,0.1μM) has 60% phototoxicity to HepG2, Si3(0.1μM) only has 17% phototoxicity, the phototoxicity enhance 3 folds if Si3 bind with BSA.