Doxorubicin hydrochloride dox

Rare earth oxides Y₂O₃ (99.99%), Yb₂O₃ (99.99%), and Er₂O₃ (99.99%) were obtained from China Rare Earth Online Co. Ltd. Rare earth chlorides (LnCl₃, Ln: Y, Gd, Yb, Er) were prepared by dissolving the corresponding oxides in hydrochloric acid and then evaporating the water completely. Ammonium fluoride (NH₄F, 98%), sodium hydroxide, hydrochloric acid, ethanol, methanol, methylene chloride, triethylamine (TEA), and dimethyl sulfoxide (DMSO) were purchased from Sinopharm Chemical Reagent Co., Ltd (China). Oleic acid (OA, 90%), 1-octadecene (ODE, 90%), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were purchased from Sigma-Aldrich. Anticancer drug doxorubicin hydrochloride (DOX, > 98%) was purchased from Shanghai Sangon Biotech Company (Shanghai China) and was deprotonated with addition of triethylamine to obtain the hydrophobic form. Carboxyl-terminated Poly(lactide-co-glycolide) (PLGA-COOH 50:50, Mw = 10000) was obtained from Jinan Daigang Bioengineer Company, China. Polyvinyl alcohol (PVA, Mw = 22000) was obtained from Kuraray CO. LTD, Japan. All reagents were used as received without further purification.

The DOX loading of Eu-FA nanorods were prepared using an absorption method. Doxorubicin hydrochloride (DOX, Shanghai Sangon, Shanghai, China) was dissolved in the PBS solution at pH 7.4 to produce stock solutions with concentrations of 0, 200, 750, 2000, 3000, 4000, and 5000 μg/mL. Five milligrams of the Eu-FA sample were ultrasonically dispersed in each DOX solution for 5 min, and then kept in a 37 °C water bath for 12 h. To quantify the drug-loading amount, the nanorods were centrifuged at 10,000 rpm for 5 min, and the supernatant was gathered and detected by UV-vis spectrophotometer at an absorbance of 483 nm.
To study the release curve of DOX from the nanocarrier samples, the as-prepared Eu-FA/DOX nanorods were used. A 2 mg sample was dispersed in a 2 mL PBS solution (0.01 M, pH 7.4 and 5.5), followed by dialysis (3500 Dalton) in an air bath oscillator at 37 °C. The dialysis bag was placed in a buffer medium of 8 mL, and the vibration was slow under the condition of 37 °C. At the different time points (15 min, 30 min, 2 h, 4 h, 8 h, 12 h, 1 h, 24 h, 36 h), the amount of drug released into the medium was measured by using a UV-Vis spectrophotometer with an absorbance of 483 nm, and the release rate was then calculated.