Department of Environmental Engineering, UNESP-São Paulo State University , Avenida Três de Março, n° 511, 18087-180 Sorocaba, SP, Brazil.
Department of Biotechnology, University of Sorocaba , Rodovia Raposo Tavares, Km 92.5, 18023-000 Sorocaba, SP, Brazil.
ACS Appl Mater Interfaces. 2016 Oct 5;8(39):25777-25787. doi: 10.1021/acsami.6b08663. Epub 2016 Sep 21.
There is increasing interest in the development of new magnetic polymeric carriers for biomedical applications such as trigger-controlled drug release, magnetic hyperthermia (MH) for the treatment of cancer, and as contrast agents in magnetic resonance imaging (MRI). This work describes the synthesis of sub-micrometer and magnetic polymer nanocomposite capsules (MPNCs) by combining in one single platform the biodegradable polymer poly-ε-caprolactone (PCL) and different concentrations of ∼8 nm oleic acid (OA)-functionalized magnetite nanoparticles (FeO@OA), employing the oil-in-water emulsion/solvent evaporation method. The MPNCs showed a significant increase in particle size from ∼400 to ∼800 nm as the magnetic loading in the organic-inorganic hybrids increases from 1.0% to 10%. The MPNCs presented high incorporation efficiency of FeO@OA nanoparticles, good colloidal stability, and super-paramagnetic properties. Interestingly, electron microscopy results showed that the FeO@OA nanoparticles were preferentially located at the surface of the capsules. Evaluation of the magnetic properties showed that the saturation magnetization and the blocking temperature of the MPNCs samples increased as a function of the FeO@OA loading. All the MPNCs exhibited heating when subjected to MH, and showed good specific absorption rates. Use of the formulations decreased the longitudinal (T) and transverse (T) relaxation times of water protons' nuclei, with excellent transverse relaxivity (r) values, especially in the case of the formulation with lowest FeO@OA loading. Furthermore, the MPNCs-cell interaction was studied, and MPNCs showed lower cellular toxicity to normal cells compared to cancer cells. These findings help in understanding the relationships between magnetic nanoparticles and polymeric capsules, opening perspectives for their potential clinical uses as simultaneous heating sources and imaging probes in MH and MRI, respectively.
人们越来越关注开发用于生物医学应用的新型磁性聚合物载体，例如触发控制药物释放、用于癌症治疗的磁热疗 (MH) 以及磁共振成像 (MRI) 中的造影剂。本工作通过在一个平台上将可生物降解的聚合物聚己内酯 (PCL) 与不同浓度的约 8nm 油酸 (OA) 功能化的磁铁矿纳米粒子 (FeO@OA) 结合，采用油包水乳液/溶剂蒸发法，合成了亚微米和磁性聚合物纳米复合胶囊 (MPNCs)。随着有机-无机杂化物中磁性负载从 1.0%增加到 10%，MPNCs 的粒径从约 400nm 显著增加到约 800nm。MPNCs 表现出高的 FeO@OA 纳米粒子的包埋效率、良好的胶体稳定性和超顺磁性。有趣的是，电子显微镜结果表明，FeO@OA 纳米粒子优先位于胶囊的表面。磁性性能评估表明，MPNCs 样品的饱和磁化强度和阻塞温度随 FeO@OA 负载的增加而增加。所有 MPNCs 在 MH 下都表现出加热效果，并表现出良好的比吸收率。这些制剂的使用降低了水质子核的纵向 (T) 和横向 (T) 弛豫时间，具有极好的横向弛豫率 (r) 值，尤其是在 FeO@OA 负载最低的制剂的情况下。此外，研究了 MPNCs 与细胞的相互作用，与癌细胞相比，MPNCs 对正常细胞的细胞毒性较低。这些发现有助于理解磁性纳米粒子和聚合物胶囊之间的关系，为它们在 MH 和 MRI 中分别作为加热源和成像探针的潜在临床应用开辟了前景。
