Nguyen Ngoc Van Thanh, Smadja Claire, Taverna Myriam, El Mousli Sirine, Secret Emilie, Siaugue Jean-Michel, Nguyen Lac Thuy Huu, Mai Thanh Duc
Université Paris-Saclay, CNRS, Institut Galien Paris-Saclay, 92296, Châtenay-Malabry, France.
Université Paris-Saclay, CNRS, Institut Galien Paris-Saclay, 92296, Châtenay-Malabry, France.
Anal Chim Acta. 2021 May 29;1161:338466. doi: 10.1016/j.aca.2021.338466. Epub 2021 Mar 29.
It is reported in this study a new approach for modulation and even suppression of the electroosmotic flow (EOF) to achieve better electrokinetic preconcentration in capillary electrophoresis. This is based on the augmentation of the buffer's concentrations to very high levels (more than a thousand of mM) without recourse to any dynamic/permanent coating nor viscous gel. The use of large weakly charged molecules as background electrolyte's constituents allows working at extreme concentration ranges without penalty of high electric currents and Joule heating. By this way, the electroosmotic mobility could be modulated over a wide range (2-60 × 10 cm V s under alkaline conditions), and suppressed to levels equivalent to those obtained with several neutral coatings. The highest buffer concentrations, and the lowest EOF magnitudes, accordingly, were achieved with diethanolamine/3-(Cyclohexylamino)-1-propanesulfonic acid (ionic strength (IS) of 250 mM, pH 9.5), Tris(hydroxymethyl)aminomethane (Tris)/2-(Cyclohexylamino)ethanesulfonic acid (CHES) (IS of 280 mM, pH 8.7) and triethanolamine/2-(Cyclohexylamino)ethanesulfonic acid (IS of 250 mM, pH 8.5). For demonstration, this new approach was applied for sensitive determination of core-shell magnetic nanoparticles (CSMNPs) having high potential for healthcare applications such as imaging agents for diagnostics and controllable cargos for nanomedicine. Different profiles were achieved for purpose-made and commercial magnetic nanoparticles using CE coupled with light-emitting-diode induced fluorescence (LEDIF) detection. The best performance for EOF-assisted preconcentration and CE-LEDIF of CSMNPs was achieved with these nanoparticles prepared in TRIS/CHES (IS 10 mM, pH 8.4) for preconcentration, and separation under BGE of TRIS/CHES (IS 100 mM, pH 8.4). Compared to the conventional capillary electrophoresis (CE-UV) method for characterization of magnetic nanoparticles, our proposed approach with fluorescent detection and EOF-assisted preconcentration offers almost 350-fold sensitivity improvement. Furthermore, our scheme can be used for monitoring the interaction between CSMNPs and target pharmaceutical molecules, serving for drug delivery development. A preliminary study with two antibiotics using this approach revealed that kanamycin interacts better with the target nanoparticles than amikacin.
本研究报道了一种调节甚至抑制电渗流（EOF）的新方法，以在毛细管电泳中实现更好的电动预浓缩。这基于将缓冲液浓度提高到非常高的水平（超过一千毫摩尔），而无需使用任何动态/永久性涂层或粘性凝胶。使用大的弱带电分子作为背景电解质的成分，可以在极端浓度范围内工作，而不会受到高电流和焦耳热的影响。通过这种方式，电渗迁移率可以在很宽的范围内调节（在碱性条件下为2 - 60×10 cm V s），并被抑制到与几种中性涂层相当的水平。相应地，使用二乙醇胺/3 -（环己基氨基）-1 - 丙磺酸（离子强度（IS）为250 mM，pH 9.5）、三（羟甲基）氨基甲烷（Tris）/2 -（环己基氨基）乙磺酸（CHES）（IS为280 mM，pH 8.7）和三乙醇胺/2 -（环己基氨基）乙磺酸（IS为250 mM，pH 8.5）可实现最高的缓冲液浓度和最低的EOF幅度。为了进行演示，这种新方法被用于灵敏测定具有高医疗应用潜力的核壳磁性纳米颗粒（CSMNP），例如用于诊断的成像剂和用于纳米医学的可控载药。使用毛细管电泳结合发光二极管诱导荧光（LEDIF）检测，针对特制的和商业磁性纳米颗粒实现了不同的图谱。对于CSMNP的EOF辅助预浓缩和CE - LEDIF，在TRIS/CHES（IS 10 mM，pH 8.4）中制备用于预浓缩，并在TRIS/CHES（IS 100 mM，pH 8.4）的背景电解质下进行分离时，获得了最佳性能。与用于表征磁性纳米颗粒的传统毛细管电泳（CE - UV）方法相比，我们提出的具有荧光检测和EOF辅助预浓缩的方法灵敏度提高了近350倍。此外，我们的方案可用于监测CSMNP与目标药物分子之间的相互作用，用于药物递送开发。使用这种方法对两种抗生素进行的初步研究表明，卡那霉素与目标纳米颗粒的相互作用比阿米卡星更好。
