PDF(Pubmed)
Abstract：
BACKGROUND: Multiwalled carbon nanotubes (MWCNTs) functionalized with lysine via 1,3-dipolar cycloaddition and conjugated to galactose or mannose are potential nanocarriers that can effectively bind to the lectin receptor in MDA-MB-231 or MCF-7 breast cancer cells. In this work, a method based on molecular dynamics (MD) simulation was used to predict the interaction of these functionalized MWCNTs with doxorubicin and obtain structural evidence that allows a better understanding of the drug loading and release process. The MD simulations showed that while doxorubicin only interacted with pristine MWCNTs through π-π stacking interactions, functionalized MWCNTs were also able to establish hydrogen bonds, suggesting that the functionalized groups improve doxorubicin loading. Moreover, the elevated adsorption levels observed for functionalized nanotubes further support this enhancement in loading efficiency. MD simulations also shed light on the intratumoral pH-specific release of doxorubicin from functionalized MWCNTs, which is induced by protonation of the daunosamine moiety. The simulations show that this change in protonation leads to a lower absorption of doxorubicin to the MWCNTs. The MD studies were then experimentally validated, where functionalized MWCNTs showed improved dispersion in aqueous medium compared to pristine MWCNTs and, in agreement with the computational predictions, increased drug loading capacity. Doxorubicin-loaded functionalized MWCNTs demonstrated specific release of doxorubicin in tumor microenvironment (pH = 5.0) with negligible release in the physiological pH (pH = 7.4). Furthermore, doxorubicin-free MWNCT nanoformulations exhibited insignificant cytotoxicity. The experimental studies yielded nearly identical results to the MD studies, underlining the usefulness of the method. Our functionalized MWCNTs represent promising non-toxic nanoplatforms with enhanced aqueous dispersibility and the potential for conjugation with ligands for targeted delivery of anti-cancer drugs to breast cancer cells.
METHODS: The computational model of a pristine carbon nanotube was created with the buildCstruct 1.2 Python script. The lysinated functionalized groups were added with PyMOL and VMD. The carbon nanotubes and doxorubicin molecules were parameterized using the general AMBER force field, and RESP charges were determined using Gaussian 09. Molecular dynamics simulations were carried out with the AMBER 20 software package. Adsorption levels were calculated using the water-shell function of cpptraj. Cytotoxicity was evaluated via a MTT assay using MDA-MB-231 and MCF-7 breast cancer cells. Drug uptake of doxorubicin and doxorubicin-loaded MWCNTs was measured by fluorescence microscopy.
METHODS: The computational model of a pristine carbon nanotube was created with the buildCstruct 1.2 Python script. The lysinated functionalized groups were added with PyMOL and VMD. The carbon nanotubes and doxorubicin molecules were parameterized using the general AMBER force field, and RESP charges were determined using Gaussian 09. Molecular dynamics simulations were carried out with the AMBER 20 software package. Adsorption levels were calculated using the water-shell function of cpptraj. Cytotoxicity was evaluated via a MTT assay using MDA-MB-231 and MCF-7 breast cancer cells. Drug uptake of doxorubicin and doxorubicin-loaded MWCNTs was measured by fluorescence microscopy.
摘要：
背景：通过1,3-偶极环加成用赖氨酸官能化并与半乳糖或甘露糖缀合的多壁碳纳米管（MWCNT）是潜在的纳米载体，可以有效地结合MDA-MB-231或MCF-7乳腺癌细胞中的凝集素受体。在这项工作中,使用基于分子动力学（MD）模拟的方法来预测这些功能化的MWCNT与阿霉素的相互作用，并获得结构证据，从而更好地了解药物的加载和释放过程。MD模拟表明，尽管阿霉素仅通过π-π堆叠相互作用与原始MWCNT相互作用，功能化的MWCNT也能够建立氢键，这表明官能化基团改善了阿霉素的负载。此外，对于官能化纳米管观察到的升高的吸附水平进一步支持负载效率的这种增强。MD模拟还揭示了多柔比星从功能化MWCNT的肿瘤内pH特异性释放，这是由daunosamine部分的质子化诱导。模拟显示质子化的这种变化导致多柔比星对MWCNT的较低吸收。然后对MD研究进行了实验验证，与原始MWCNT相比，官能化MWCNT在水性介质中的分散性得到改善，与计算预测一致，增加药物装载能力。负载阿霉素的官能化MWCNT显示阿霉素在肿瘤微环境(pH=5.0)中的特异性释放,而在生理pH(pH=7.4)中的释放可忽略。此外，不含多柔比星的MWNCT纳米制剂表现出微不足道的细胞毒性。实验研究产生了与MD研究几乎相同的结果，强调该方法的有用性。我们的功能化MWCNT代表了有希望的无毒纳米平台，具有增强的水分散性和与配体缀合的潜力，用于将抗癌药物靶向递送至乳腺癌细胞。
方法：原始碳纳米管的计算模型是使用buildClstruct1.2Python脚本创建的。用PyMOL和VMD加入裂解的官能化基团。使用一般的AMBER力场对碳纳米管和阿霉素分子进行参数化，和RESP电荷使用高斯09测定。使用AMBER20软件包进行分子动力学模拟。使用cpptraj的水壳函数计算吸附水平。通过使用MDA-MB-231和MCF-7乳腺癌细胞的MTT测定来评估细胞毒性。通过荧光显微镜测量阿霉素和负载阿霉素的MWCNT的药物摄取。
方法：原始碳纳米管的计算模型是使用buildClstruct1.2Python脚本创建的。用PyMOL和VMD加入裂解的官能化基团。使用一般的AMBER力场对碳纳米管和阿霉素分子进行参数化，和RESP电荷使用高斯09测定。使用AMBER20软件包进行分子动力学模拟。使用cpptraj的水壳函数计算吸附水平。通过使用MDA-MB-231和MCF-7乳腺癌细胞的MTT测定来评估细胞毒性。通过荧光显微镜测量阿霉素和负载阿霉素的MWCNT的药物摄取。
