Hplc system l 7100

The Cy5-NHS was used to label the iRGD peptide by the reaction of NHS with the amino group of iRGD. The reaction was conducted by mixing 0.3 mg of Cy5-NHS and 0.5 mg of iRGD (molar ratio 1:1) in 1 mL sodium bicarbonate buffer (pH 6.5). Then the Cy5 labeled peptide were purified by using a Hitachi HPLC system (L-7100, Hitachi, Japan). The Doxorubicin (DOX) and Cy5 loaded liposomes were prepared based on a modified single step preparation method [26 (link)]. Stock solutions of DSPE-PEG and lecithin were prepared separately at the concentrations of 1 mg/mL in 4% ethanol aqueous solution. Stock solutions of PLGA were prepared at the concentration of 2.5 g/mL in acetone. DOX and Cy5 were dissolved in water at the concentrations of 1 mg/mL and 0.1 mg/mL, respectively. The stock solutions of DSPE-PEG and lecithin were added into ddH₂O and then the PLGA solution mixed with DOX or Cy5 was carefully pipetted into the resulting aqueous solution under sonication for 20 min at 100 W. The ratio of the used amount of aqueous solution to that of organic solution was 10:1. The prepared nanoparticles were purified and washed three times with a centrifugal filter (MW: 10 K) and characterized with TEM. Dynamic light scattering was used to analyze the size and surface zeta potential of the prepared nanoparticles.