Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 7 York Road, Parktown 2193, South Africa.
Department of Applied Chemistry, University of Johannesburg, 27 Nind Street, Doornfontein, Johannesburg 2028, South Africa.
Molecules. 2018 Jun 10;23(6):1406. doi: 10.3390/molecules23061406.
The complete synthesis, optimization, purification, functionalization and evaluation of vertically aligned multiwalled carbon nanotubes (VA-MWCNTs) was reported for potential application in dexamethasone delivery to the ischemic brain tissue. The conditions for high yield were optimized and carbon nanotubes functionalized and PEGylated prior to dexamethasone loading. Morphological changes were confirmed by SEM and TEM. Addition of functional groups to MWCNTs was demonstrated by FTIR. Thermal stability reduced following MWCNTs functionalization as demonstrated in TGA. The presence of carbon at 2θ of 25° and iron at 2θ of 45° in MWCNTs was illustrated by XRD. Polydispersive index and zeta potential were found to be 0.261 and −15.0 mV, respectively. Dexamethasone release increased by 55%, 65% and 95% in pH of 7.4, 6.5 and 5.5 respectively as evaluated by UV-VIS. The functionalized VA-MWCNTs were demonstrated to be less toxic in PC-12 cells in the concentration range from 20 to 20,000 µg/mL. These findings have demonstrated the potential of VA-MWCNTs in the enhancement of fast and prolonged release of dexamethasone which could lead to the effective treatment of ischemic stroke. More work is under way for targeting ischemic sites using atrial natriuretic peptide antibody in stroke rats.
垂直排列多壁碳纳米管（VA-MWCNTs）的完全合成、优化、纯化、功能化和评估，以用于将地塞米松递送至缺血性脑组织的潜在应用。优化了高产的条件，并在负载地塞米松之前对碳纳米管进行了功能化和 PEG 化。通过 SEM 和 TEM 确认了形态变化。通过 FTIR 证明了 MWCNTs 上添加了官能团。MWCNTs 功能化后热稳定性降低，如 TGA 所示。MWCNTs 中在 2θ 处的碳存在于 25°，铁存在于 2θ 处 45°，如 XRD 所示。多分散指数和 zeta 电位分别为 0.261 和-15.0 mV。通过 UV-VIS 评估，在 pH 为 7.4、6.5 和 5.5 时，地塞米松的释放量分别增加了 55%、65%和 95%。研究表明，在 20 至 20,000 µg/mL 的浓度范围内，功能性 VA-MWCNTs 在 PC-12 细胞中毒性较低。这些发现表明，VA-MWCNTs 具有增强地塞米松快速和持续释放的潜力，从而可能有效治疗缺血性中风。正在进行更多的工作，以使用心房利钠肽抗体在中风大鼠中靶向缺血部位。
