Preparation Of Phenothiazinium Photosensitizer Modified Magnetic Particles For Blood Virus Inactivation

In this research, dye-containing magnetic particles were prepared by using functionalized magnetic microparticles with carboxyl group or epoxy group on its surface, and then the phenothiazinium photosensitizers, such as azure A and azure B, which have strong photo-induced virus inactivation activity were coupled onto the magnetic microparticles by several different methods. This kind of material has the super-paramagnetic feature, which makes it easy to separate the photosensitizer modified particles from blood products after photochemical virus inactivation, so the problem of dye residue is completely resolved. The material was applied for virus inactivation in blood products, using cytopathic effect experiment to titer the indicator virus infectivity and Reed-Muench method to calculate virus inactivation efficiency, and the result indicated the excellent activity of the material.In the part of the preparation of the phenothiazinium photosensitizer modified particles, super-paramagnetic Fe₃O₄ microparticles were prepared by chemical co-precipitation method firstly; Secondly, epoxy group or carboxyl group were subsequently introduced to the Fe₃O₄ particle surface as molecular anchor by silylation; Then, crosslink reagent, such as EDC and DCC, were used to catalyze the reaction for coupling AA or AB to the surface of carboxyl-terminated particles; Meanwhile, organometallic reagent Sn (II) triflate catalyzed method, FeCl₃-ultrasonic irradiation mediated method and alkali catalyzed method were tried to covalently couple AA or AB onto the epoxy-terminated particles. Comparing all the methods mentioned above, alkali-catalyzed method performed the best. Finally, the alkali-catalyzed method was optimized to improve the content of photosensitizer on the particles and the coupling amounts of AA and AB, which were determined by UV-Vis spectrometry, are up to 50 nmol/mg and 37 nmol/mg, respectively.Further more, researched on the relationship between the light absorption of phenothiazinium photosensitizers and the pH value of the solution, which can be guidance for determining the dye-coupling amount by UV-Vis method. Studied on the stability of AA/AB in different pH value PB buffer, the result of the experiment indicated that the maximum pH value borderline for oxidation-decomposition is 11.5 (AA) and 12.0 (AB). So the experiment provided the guidance for the optimization of the pH value.In the photo-induced virus inactivation experiment, the PRV was used as indicating virus and the inactivation system was optimized by varying the irradiation time, irradiation aera and concentration of the photosensitizer modified particle, etc. The materials were applied for several blood products, such as the plasma, hemoglobin solution and poly-hemoglobin solution. The result indicated that the material performed excellently, with more than 4 LgTCID₅₀ reduction of PRV titer. In conclusion, the virus inactivation activity of photosensitizer modified particles showed strong potential in the hemopurification field.The capability of singlet oxygen yield was determined by the oxidation-extraction UV method, in which the DPCI was used as the singlet oxygen (¹O₂) capture-agent. So the dye coupling amount was detected indirectly.