Stable encapsulation of medically active compounds can lead to longer storage life and facilitate the slow-release mechanism. In this work, the dynamic and molecular interactions between plumbagin molecule with β-cyclodextrin (BCD) and its two derivatives, which are dimethyl-β-cyclodextrin (MBCD), and 2-O-monohydroxypropyl-β-cyclodextrin (HPBCD) were investigated. Molecular dynamics simulations (MD) with GLYCAM-06 and AMBER force fields were used to simulate the inclusion complex systems under storage temperature (4 °C) in an aqueous solution. The simulation results suggested that HPBCD is the best encapsulation agent to produce stable host–guest binding with plumbagin. Moreover, the observation of the plumbagin dynamic inside the binding cavity revealed that it tends to orient the methyl group toward the wider rim of HPBCD. Therefore, HPBCD is a decent candidate for the preservation of plumbagin with a promising longer storage life and presents the opportunity to facilitate the slow-release mechanism.

Ion transport is a significant concept that underlies a variety of technologies including membrane technology, energy storages, optical, chemical, and biological sensors and ion-mobility exploration techniques. These applications are based on the concepts of capacitance and ion transport, so a prior understanding of capacitance and ion transport phenomena is crucial. In this review, the principles of capacitance and ion transport are described from a theoretical and practical point of view. The review covers the concepts of Helmholtz capacitance, diffuse layer capacitance and space charge capacitance, which is also referred to as quantum capacitance in low-dimensional materials. These concepts are attributed to applications in the electrochemical technologies such as energy storage and excitable ion sieving in membranes. This review also focuses on the characteristic role of channel heights (from micrometer to angstrom scales) in ion transport. Ion transport technologies can also be used in newer applications including biological sensors and multifunctional microsupercapacitors. This review improves our understanding of ion transport phenomena and demonstrates various applications that is applicable of the continued development in the technologies described.

Nicotine is widely used in pharmaceutical industries, especially for smoking cessation in the form of transdermal patches. Nicotine gel in the patches has limitations from nicotine instability and high volatility. Thus, a nicotine preservation technique is needed. In this study, a nicotine encapsulation process using methyl-β-cyclodextrin (MβCD) is investigated and compared with β-cyclodextrin (βCD) to evaluate the preservation and skin permeation of nicotine. The M06-2X/6-31G(d,p) density functional theory calculations indicate a 1:1 host–guest molar ratio for the inclusion complex of nicotine with βCD and MβCD, which have been validated by experimental studies. The encapsulation efficiencies of βCD and MβCD to encapsulate nicotine are 59.96% and 63.76%, respectively. The preservation study of the inclusion complexes compared to pure nicotine shows a stability improvement of nicotine after being encapsulated. After 21 days, the percentages of the nicotine/βCD and nicotine/MβCD inclusion complexes that remain are 89.32% and 76.22%, while only 65.56% of pure nicotine remains. Besides the one-hour skin permeation tests, the amounts of nicotine permeated through pig skin from the nicotine/βCD and nicotine/MβCD inclusion complex gels are 14 and 10 times as much as the pure nicotine gel, respectively. Therefore, the encapsulation of nicotine with βCD and MβCD can be used to enhance the stability and skin permeation application of nicotine-containing products.