| Objective: In order to obtain the optimum release conditions,the influence factors on release of DOX in the dialysis bag were explored.To study the optimum synthesis condition,cytotoxicity,loading properties and release properties of Ni and Ni@C nanotubes,and then establish foundation for the research of new tabular drug nanocarries.Methods: Using DOX as a drug model,the equilibration time and cumulative release rate of DOX under the different conditions were researched by different specifications dialysis bag,p H and concentration of PBS medium,and then the optimum release conditions were obtained.Moreover,the absorbance of DOX in the medium was detected by UV-vis and the surface morphologies of the dialysis bags were characterized by SEM.Different Ni nanotubes were prepared using the template-assisted chemical deposition.The influence of template,nickel source,solvent and time on the formation of nickel nanotubes was investigated.The sizes,morphologies,strctures,compositions and magnetic properties of the prepared Ni nanotubes were characterized by SEM,TEM,XRD and VSM.The cytotoxicity,cell apoptosis and cell cycle of Ni nanotubes were studied by MTT experments and flow cytometry.The stability of Ni nanotubes was also carried on by the acid dissolution test,and the DOX release behaviors for Ni nanotubes under the different p H were also analyzed by UV-vis.Using glucose as the cabon source,the carbon-coated Ni nanotbues were obtained by the solvothermal method.The sizes,morphologies,strctures,compositions and magnetic properties of the prepared Ni@C nanotubes were characterized by SEM,TEM,XRD,Raman,EDX maping and VSM.The cytotoxicity,cell apoptosis and cell cycle of Ni@C nanotubes were also studied by MTT experments and flow cytometry.The stability of Ni@C nanotubes was carried on by the acid dissolution test,and the DOX release behaviors of Ni@C nanotubes under the different p H were also analyzed by UV-vis.Results: The actual average pore size of the 1000 k Da dialysis bag is about 120 nm,but that of 3500 Da dialysis bag is less than 10 nm.For 3500 Da dialysis bag,DOX can reach release balance at 180 min.Under three p H values,the cumulative release rates of DOX in the PBS medium with concentration of 0.001,0.01 and 0.025 mol·L-1 are about 68%(2.0),86%(2.0),98%(2.0),62%(5.0),76%(5.0),94%(5.0),42%(7.4),44%(7.4)and 75%(7.4).However,for 1000 k Da dialysis bag,DOX can reach release balance at 160 min.Under three p H values,the cumulative release rates of DOX in the PBS medium with concentration of 0.001,0.01 and 0.025 mol·L-1 are about 88%(2.0),93%(2.0),100%(2.0),84%(5.0),88%(5.0),98%(5.0),32%(7.4),38%(7.4),81%(7.4).The Ni nanotubes with diameter of 80 nm,280 nm and 0.2 ?m can be obtained by changing the template specifications.The Ni nanotubes can be fabricated in aqueous solution at 1,2 and 3 min,but the prepared PC template is harder to polish.In mixed solvent of alcohol and water with the volume ratio of 2:1,the aspect ratio of the prepared Ni nanotubes is bigger and PC template is easy to polish.In mixed solvent of alcohol and water with the volume ratio of 1:1,the Ni nanotubes can be obtained with ununiform shape.However,using alcohol as solvent,the prepared Ni nanotubes are relatively broken with different lengt.The Hc,Ms and Mr of the Ni nanotubes synthesized at the optimum condition are 304.7 Oe,1.15 emu·g-1 and 3.6 emu·g-1,individually.Incubated with 1~250 ?g·m L-1 Ni nanotubes,the cell viability of changliver and Hep G2 are 6%~82% and 6.44%~94.64%,respectively.Incubated with 10 ?g·m L-1(20 ?g·m L-1)Ni nanotubes,the early and late apoptosis rates are 7.7%(23.9%)and 8.6%(22.3%),and the proportion of cells in G1,G2 and S are 29.70%(9.24%),29.10%(12.08%7)and 41.20%(5.67%).Furthermore,the DOX loading efficiency of the prepared Ni nanotubes is up to 99%.The cumulative release rates of Ni@DOX with 1000 k Da dialysis bag under the different p H value at 120 h are 45%(7.4),61%(5.0),73%(2.0),individually.The carbon layer thickness of Ni@C is about 10 nm,and its surface contains amino functional groups.The Hc,Ms and Mr of the Ni@C nanotubes are 25.3 Oe,18.05 emu·g-1 and 5.97 emu·g-1,individually.The toxicity on changliver and Hep G2 cells is very small when the concentration of Ni@C is less than 50 ?g·m L-1.Incubated with 10 ?g·m L-1(20 ?g·m L-1)Ni nanotubes,the early and late cell apoptosis rates are 3.2%(8.0%)and 6.4%(8.1%),the proportion of cells in G1,G2 and S are 49.82%(25.72%),11.59%(21.62%)and 38.59%(56.66%).Moreover,the DOX loading efficiency of the prepared Ni@C nanotubes still remains at 99%.The cumulative release rates of Ni@C@DOX with 1000 k Da dialysis bag at 50 h are 20%(7.4),54%(5.0)and 55%(2.0),individually.Conclusion: DOX is easier to release with the larger pore diameter dialysis bag,smaller p H value and greater concentration of PBS.The Ni nanotubes is had better synthesized with 0.2 ?m PC membrane in mixed solvent(water/alcohol = 2:1)for 2.0 min.The prepared Ni nanotubes have some maganic properties,stability and cytotoxicity,which can induce Hep G2 cell apoptosis.The Ni nanotubes have high DOX load efficiency and exhibit certain acid sensitive release properties.The Ni@C nanotubes obtained by solvothermal method have obvious hollow structure and uniform thickness of carbon layer.Camparing with Ni nanotubes,the Ni@C nanotubes have better maganic properties,lower cytotoxicity,similar loading efficiency and bigger acid sensitive release performance. |
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