Abstract

Folate-modified carboxymethyl chitosan (FCMC) was made by using folate acid as targeted group and attaching folate to carboxymethyl chitosan, and then targeted FCMC/CaCO₃ hybrid nanosphere were formed by self-assembly of calcium carbonate in FCMC solution. The physicochemical properties of the nanospheres were investigated by fourier transform infrared spectroscopy (FTIR) X-ray diffraction analysis (XRD) Brunauer-Emmett-Teller (BET) measurement and thermogravimetric analysis (TGA). The results showed that the FCMC/CaCO₃ hybrid nanospheres were composed of calcite, vaterite and polysaccharides, and the content of organic compounds was 12.17%. Also, the structure performance of the hybrid nanospheres was analyzed. Besides, the effects of the hybrid nanospheres on the encapsulation efficiency, the drug loading content and the release behavior were also analyzed with the metformin (MET) as a model drug. Scanning electron microscope (SEM), Zeta potential analysis and UV-vis were used to characterize the hybrid nanospheres. Under the conditions of FCMC/Ca²⁺ molar ratio of 4: 1 and reaction for 24 h, the achieved results showed that the spherical aggregates with regular morphology were obtained and the average particle size of the nanospheres was 207 nm. The specific surface area of the hybrid nanosphere is 27.06 m²·g ⁻¹ and the average pore diameter of the sample is 3.84 nm, indicating the presence of mesoporous structure in the sample. This mesoporous structure can supply potential space for adsorption of anticancer drugs. Additionally, the surface charge of the nanoparticles was positive and the entrapment efficiency was 83.32%. The hybrid nanospheres have a capability of effective pH-sensitivity controlled drug release. All the drug loaded hybrid nanospheres successfully sustained the release of MET at pH 7.4, only about 44.58% of the drug released in 6 days. While under acidic condition (pH 5.0) drug release was significantly accelerated, being over 98.85% of the drug released. The hybrid nanospheres demonstrated an excellent smart drug delivery behavior.

摘要

以叶酸为目标基团，将叶酸与羧甲基壳聚糖结合，制备了叶酸修饰的羧甲基壳聚糖（FCMC），然后通过在FCMC溶液中自组装碳酸钙，形成了靶向的FCMC / CaCO ₃杂化纳米球。通过傅里叶变换红外光谱（FTIR）X射线衍射分析（XRD）Brunauer-Emmett-Teller（BET）和热重分析（TGA）研究了纳米球的理化性质。结果表明，FCMC / CaCO ₃杂化纳米球由方解石，球ate石和多糖组成，有机物含量为12.17％。此外，分析了杂化纳米球的结构性能。此外，还以二甲双胍（MET）为模型药物，分析了杂化纳米球对包封率，载药量和释放行为的影响。扫描电子显微镜（SEM），Zeta电位分析和UV-vis用于表征杂化纳米球。在FCMC / Ca ²⁺摩尔比为4：1的条件下反应24 h，得到的结果表明，所得到的球形聚集体具有规则的形貌，纳米球的平均粒径为207 nm。杂化纳米球的比表面积为27.06 m ²· g ^-1，样品的平均孔径为3.84 nm，表明样品中存在中孔结构。这种介孔结构可以为抗癌药物的吸附提供潜在的空间。另外，纳米颗粒的表面电荷为正，并且包封效率为83.32％。杂化纳米球具有有效控制pH敏感性的药物释放的能力。所有载有药物的杂化纳米球在pH 7.4下成功地维持了MET的释放，仅占6天释放药物的44.58％。在酸性条件下（pH 5.0），药物释放明显加快，占药物释放的98.85％以上。杂化纳米球表现出优异的智能药物递送行为。