A study of conjugation of FePt/ZnS nanocore-shell structure with different sequences of DNAs

The paper attempts to develop a nanocore-shell structure with photomagnetic nature, and let it undergo conjugation reaction with the DNAs of different sequences in order to apply the structure to target-based drug therapy and biomedical-related areas. First of all, iron platinum (FePt) magnetic nanofluid with average particle size 20 nm is prepared by chemical method. After that, zinc sulfide with fluorescent nature is used to modify the surface of nanoparticles so as to form a core-shell structure. The thickness of shell in such core-shell structure can be controlled at 5-10 nm by fabrication process. The FePt nanoparticles being modified by zinc sulfide not only can enhance the dispersed suspension of nanoparticles, but is also proved by fluorescence spectrometer to have good optical nature. The prepared nanocore-shell structured particles are conjugated with two groups of DNA of different sequences respectively. Through a bridge DNA, hybridization is undergone for two groups of DNA of different sequences having completed conjugation reaction, making these two groups of DNA of different sequences connect with each other. Finally, after the unconjugated DNA primers are removed, the hybridization among the DNAs of different sequences is finished. AO dye is used to test the conjugation effect of DNA, and the result shows that there is green fluorescent reaction, thus proving that conjugation is caused to dsDNA. Besides, UV-vis spectrophotometer is used to test the conjugation efficiency between DNA and nanocore-shell structured particles, which is found to be as high as above 90%.