The Design, Synthesis And Photosensitivity Of Amino Acid Phthalocyanines With Different Charging Properties

Phthalocyanines(Pcs)are considered as promising photosensitizers due to their strong absorption in the phototherapeutic window,ease of modification,good photothermal stability and high reactive oxygen species(ROSs)generation ability.Therefore,great attentions have been paid to them in the field of photodynamic therapy(PDT).Charge properties of Pcs are closely related to their solubility,tumor cell uptake and photosensitive anticancer activity.Thus,in this dissertation,from the viewpoint of charge properties,a series of amino acid substituted Pcs with different charge properties were designed and synthesized,thereafter,the influences of charge on solubility,tumor cell uptake and photosensitive activity of them were studied,and finally ideal Pcs with good water solubility,high cellular uptake efficiency and excellent photodynamic anticancer activity were obtained.The above work may provide new ways of solving problems of Pcs used in PDT.The results are as follows:1.18 precursors and 12 amino acid substituted Pcs of differing charge were designed and synthesized.Among these compounds,14 precursors and 11 Pcs have never been reported.All of the above compounds were characterized with IR spectra,UV-Vis spectra,1H-NMR,13C-NMR,MS and elemental analyses.Zeta potential results showed that under physiological conditions,ENZnPc(negatively charged),NEZnPc(neutral)and EPZnPc(positively charged)are alanine Pcs of differing charge;QZnPcl and QZnPc2 are quatemized alanine Pcs;ArgZnPcl and ArgZnPc2 are arginine substituted Pcs which are positively charged in a wide pH range;TyrZnPc(tyrosine substituted),AspZnPc(asparagic acid substituted),GluZnPc(glutamic acid substituted),LysZnPc(lysine substituted)and OGluZnPc(octa-glutamic acid substituted)are charge changeable Pcs in response to environmental pH.2.The properties such as solubility and photosensitive activities of alanine Pcs with same skeleton structure but with different charge properties were studied.The results showed that the water solubility of charged alanine Pcs under physiological conditions is better than the neutral ones.The positively charged alanine Pc which can dissolve both in water and in some organic solvents is an amphiphilic compound.The positively charged alanine Pc showed the best singlet oxygen generation ability,cellular uptake efficiency and in vitro anticancer activity among the three alanine Pcs.3.The effects of changes in solution pH on properties such as aggregation and photosensitive activities of QZnPc1 and QZnPc2 were explored.The results showed that base additive can greatly reduce the aggregation of QZnPcl,but has no significant effects on the aggregation of QZnPc2;acid additive has less influence on both QZnPc1 and QZnPc2.The study showed that base additive can promote a shift in the amide/imidohydrine balance toward imidohydrine,and the formation of hyperconjugation makes it stably exist in water,that’s why the base additives can reduce aggregation of QZnPc1;as for QZnPc2,the methylene group block the conjugation between imidohydrine and benzene,which leads to the instability of imidohydrine,and thus base additive cannot reduce aggregation of it.Photosensitive activity test results showed that the singlet oxygen generation ability and photosensitive activity of QZnPc1 were significantly enhanced when its aggregate degree was decreased.This pH inducing tautomeric transformation could be a novel way to generate low aggregated Pcs.4.Through the study of charge properties and photosensitive activities of ArgZnPc1 and ArgZnPc2,it can be found that ArgZnPc1 and ArgZnPc2 not only had good water solubility but also could be positively charged in pH range from 5 to 9 which overcomes the drawbacks of deprotonation of protonated Pcs in physiological conditions.The above results could be attributed to the existence of arginine guanidine substituents.ArgZnPc1 had high singlet oxygen and intracellular reactive oxygen species generation abilities,good photo-stability,excellent cellular uptake efficiency(cell uptake rate was 95.96%after 24 h)as well as photosensitive anticancer activity(cell survival rate was 84.1%after treatment).However,it also interacted with biomacromolecule(Bovine serum albumin,BSA)strongly(BSA fluorescence quenching constants Kq=9.1 × 1012 L/mol).5.The photosensitive activities of pH responsive amino acid substituted Pcs were studied in normal physiological environment(pH≈7.4)and tumor microenvironment(pH≈6.5).The zeta potential results showed that the isoelectric pHs of GluZnPc and OGIuZnPc were 6.83 and 7.01,respectively,leading them to be negatively charged(Zeta potentials were-10 mV and-15 mV,respectively)at pH 7.4,and positively charged(Zeta potentials were+5 mV and+9 mV,respectively)at pH 6.5;while the isoelectric pHs of TyrZnPc,AspZnPc and LysZnPc were 5.96,6.38 and 7.82,respectively,so when the environmental pH decreased from 7.4 to 6.5,their charge would not reverse.The singlet oxygen generation ability,cellular uptake rates,in vitro photosensitive anticancer activity and fluorescence quenching constant of BSA of OGluZnPc and GluZnPc were higher at pH 6.5 than at pH 7.4.This can be attributed to the tumor microenvironment-responsive charge reversal ability of them.In contrast,no obvious photosensitive activity differences were found for the other three Pcs at different pHs.Through tumor microenvironment-responsive charge reversal,OGluZnPc and GluZnPc can be positively charged in tumor microenvironment and negatively charged in normal physiological environment,leading to safe blood transmission and tumor targeting photosensitive activity.The above work may provide valuable reference for the design of novel Pcs with good water solubility,high tumor cell uptake efficiency and excellent photosensitive anticancer activity.