Laboratorio de Estudios Crystalográficos, IACT (CSIC-UGR), Avenida de las Palmeras, 4. 18100 Armilla, Granada, Spain.
Langmuir. 2013 Jul 2;29(26):8213-21. doi: 10.1021/la4008334. Epub 2013 Jun 18.
In this work, the efficiency of bioinspired citrate-functionalized nanocrystalline apatites as nanocarriers for delivery of doxorubicin (DOXO) has been assessed. The nanoparticles were synthesized by thermal decomplexing of metastable calcium/citrate/phosphate solutions both in the absence (Ap) and in the presence (cAp) of carbonate ions. The presence of citrate and carbonate ions in the solution allowed us to tailor the size, shape, carbonate content, and surface chemistry of the nanoparticles. The drug-loading efficiency of the two types of apatite was evaluated by means of the adsorption isotherms, which were found to fit a Langmuir-Freundlich behavior. A model describing the interaction between apatite surface and DOXO is proposed from adsorption isotherms and ζ-potential measurements. DOXO is adsorbed as a dimer by means of a positively charged amino group that electrostatically interacts with negatively charged surface groups of nanoparticles. The drug-release profiles were explored at pHs 7.4 and 5.0, mimicking the physiological pH in the blood circulation and the more acidic pH in the endosome-lysosome intracellular compartment, respectively. After 7 days at pH 7.4, cAp-DOXO released around 42% less drug than Ap-DOXO. However, at acidic pH, both nanoassemblies released similar amounts of DOXO. In vitro assays analyzed by confocal microscopy showed that both drug-loaded apatites were internalized within GTL-16 human carcinoma cells and could release DOXO, which accumulated in the nucleus in short times and exerted cytotoxic activity with the same efficiency. cAp are thus expected to be a more promising nanocarrier for experiments in vivo, in situations where intravenous injection of nanoparticles are required to reach the targeted tumor, after circulating in the bloodstream.
在这项工作中，评估了仿生柠檬酸官能化纳米晶磷灰石作为阿霉素（DOXO）递送纳米载体的效率。纳米粒子通过不稳定的钙/柠檬酸盐/磷酸盐溶液的热解络合来合成，在不存在（Ap）和存在（cAp）碳酸根离子的情况下。溶液中柠檬酸和碳酸根离子的存在使我们能够调整纳米粒子的尺寸、形状、碳酸根含量和表面化学性质。通过吸附等温线评估了两种磷灰石的药物负载效率，发现其符合 Langmuir-Freundlich 行为。从吸附等温线和 ζ-电位测量中提出了一种描述磷灰石表面与 DOXO 相互作用的模型。DOXO 作为二聚体通过带正电荷的氨基吸附，该氨基与纳米粒子的带负电荷的表面基团静电相互作用。在 pH 值为 7.4 和 5.0 下分别模拟血液循环中的生理 pH 值和内涵体溶酶体中的更酸性 pH 值探索了药物释放曲线。在 pH 值为 7.4 下 7 天后，cAp-DOXO 的药物释放量比 Ap-DOXO 少约 42%。然而，在酸性 pH 值下，两种纳米组装体释放的 DOXO 量相似。通过共聚焦显微镜分析的体外试验表明，两种载药磷灰石都被内吞进入 GTL-16 人癌细胞，并能释放 DOXO，DOXO 可在短时间内积累在细胞核中，并以相同的效率发挥细胞毒性作用。因此，cAp 有望成为体内实验更有前途的纳米载体，在需要静脉注射纳米粒子到达靶向肿瘤的情况下，在血液循环中循环后，到达靶向肿瘤。
