Academic literature on the topic 'Synthetic ionic channels'

Selective ion transportation through synthetic ion channels in polymeric membranes (which mimic natural systems, e.g. excitable cell membranes) is being reported through this article. The synthetic ion channels have been created by swift heavy ion irradiation of polymeric membranes followed by chemical etching. Since, the transportation of sodium and potassium ions of aqueous electrolytes through synthetic ion channels in polyethylene terephthalate depends on the electrophoretic forces present in the electrolyte; these ion channels are referred to as “voltage activated channels”. For a particular range of applied voltage, these channels behave as K-channels while they act as Na-channels in another voltage range. The channels have been found to switch between high and low conduction states referred to as opening and closing of ion channels with applied potential. A mechanism is being proposed to explain the voltage dependent ion selectivity of the channels in both closed and open states. Nonlinear dynamical analysis of ion transportation and current oscillations confirm its chaotic behavior. Their possible applications as ionic switches and ionic flip-flops are discussed.

A synthetic peptide of the NH2-terminal inactivation domain of the ShB channel blocks Shaker channels which have an NH2-terminal deletion and mimics many of the characteristics of the intramolecular inactivation reaction. To investigate the role of electrostatic interactions in both peptide block and the inactivation process we measured the kinetics of block of macroscopic currents recorded from the intact ShB channel, and from ShB delta 6-46 channels in the presence of peptides, at different ionic strengths. The rate of inactivation and the association rate constants (k(on)) for the ShB peptides decreased with increasing ionic strength. k(on) for a more positively charged peptide was more steeply dependent on ionic strength consistent with a simple electrostatic mechanism of enhanced diffusion. This suggests that a rate limiting step in the inactivation process is the diffusion of the NH2-terminal domain towards the pore. The dissociation rates (k(off)) were insensitive to ionic strength. The temperature dependence of k(on) for the ShB peptide was very high, (Q10 = 5.0 +/- 0.58), whereas k(off) was relatively temperature insensitive (Q10 approximately 1.1). The results suggest that at higher temperatures the proportion of time either the peptide or channel spends in the correct conformation for binding is increased. There were two components to the time course of recovery from block by the ShB peptide, indicating two distinct blocked states, one of which has similar kinetics and dependence on external K+ concentration as the inactivated state of ShB. The other is voltage-dependent and at -120 mV is very unstable. Increasing the net charge on the peptide did not increase sensitivity to knock-off by external K+. We propose that the free peptide, having fewer constraints than the tethered NH2-terminal domain binds to a similar site on the channel in at least two different conformations.

Angstrom-scale fluidic channels are ubiquitous in nature and play an important role in regulating cellular traffic, signaling, and responding to stimuli. Synthetic angstrom channels are now a reality with the emergence of several cutting-edge bottom-up and top-down fabrication methods. In particular, the use of atomically thin 2D materials and nanotubes as components to build fluidic conduits has pushed the limits of fabrication to the angstrom scale. Here, we provide an overview of recent developments in the fabrication methods for nano- and angstrofluidic channels while categorizing them on the basis of dimensionality (0D pores, 1D tubes, 2D slits), along with the latest advances in measurement techniques. We discuss the ion transport governed by various stimuli in these channels and the variation of ionic mobility, streaming power, and osmotic power with pore size across all the dimensionalities. Finally, we highlight unique future opportunities in the development of smart ionic devices.

Macroscopic currents in Na channels were recorded from adult frog skeletal muscle under voltage clamp as various toxins were added to the bathing medium. Veratridine, cevadine, and 3-(4-ethoxybenzoyl)-veracevine modified the Na channels in a use-dependent manner during depolarizations and held them open for 3, 2.4, and 1.2 s, respectively, at -90 mV. The three alkaloids modified channels in the same way. Activation gating was shifted about -100 mV by the modification, and reversible closing of the channels by strong hyperpolarizations slowed reversal of the modification. The synthetic insecticides deltamethrin, EDO, GH739, and GH414 also modified channels during depolarizations that opened channels. The modification lasted 3 s with deltamethrin, but only 3-5 ms with the others. Hyperpolarization speeded the shutting off of current in insecticide-modified channels, but no reversible activation gating could be demonstrated. The ionic selectivity, PNa/PNH4, of channels was decreased by all of the toxins. This ratio was 0.11 in normal channels, 0.26 in insecticide-modified channels, and 0.7-1.6 in veratrum-alkaloid-modified channels. During use-dependent modification, the veratrum alkaloids reduced the total Na current markedly, while deltamethrin did not. Thus, alkaloid and insecticide modifications share many features but differ in how much the conducting properties of the pore are changed and whether the channel can close reversibly while the toxin remains bound.

The one-sided action of the polyene antibiotic, amphotericin B, on phospholipid bilayer membranes formed from synthetic phosphatidylcholines (DOPC and DPhPC) and sterols (ergosterol and cholesterol), has been investigated. We found formation of well-defined ionic channels for both sterols and not only for ergosterol-containing membranes (Bolard, J., P. Legrand, F. Heitz, and B. Cybulska. 1991. Biochemistry. 30:5707-5715). Characteristics of these channels were studied in the presence of different salts. It was found that the channels have comparable conductances but different lifetimes that are approximately 100-fold less in cholesterol-containing membranes than in ergosterol-containing ones. Channel blocking by tetraethylammonium (TEA) ions shows that TEA blockage of channels in the presence of cholesterol increases their lifetimes in analogy to the lengthening of lifetimes of protein channels blocked by local anesthetics (Neher, E., and J. H. Steinbach. 1978. J. Physiol. 277: 153-176). However, the effect of the blocker on single-channel conductance is very close for both sterols. The data support the classical model of amphotericin B pore formation from complexes initially lying on the membrane surface as nonconducting prepores. We explain the antibiotic's cytotoxic selectivity by differences in the lifetimes of the channels formed with different sterols and suggest that phosphatidylcholine-sterol membranes can be used as a tool for rapid estimation of polyene antibiotic cytotoxicity.

DNA nanotechnology makes use of hydrophobically modified constructs to create synthetic membrane protein mimics. However, nucleic acid structures exhibit poor insertion efficiency, leading to a low activity of membrane-spanning DNA protein mimics. It is suggested that non-ionic surfactants improve insertion efficiency, partly by disrupting hydrophobicity-mediated clusters. Here, we employed confocal microscopy and single-molecule transmembrane current measurements to assess the effects of the non-ionic surfactant octylpolyoxyethylene (oPOE) on the clustering behavior and membrane activity of cholesterol-modified DNA nanostructures. Our findings uncover the role of aggregation in preventing bilayer interactions of hydrophobically decorated constructs, and we highlight that premixing DNA structures with the surfactant does not disrupt the cholesterol-mediated aggregates. However, we observed the surfactant’s strong insertion-facilitating effect, particularly when introduced to the sample separately from DNA. Critically, we report a highly efficient membrane-spanning DNA construct from combining a non-aggregating design with the addition of the oPOE surfactant.

Abstract We describe a hybrid simulation technique that uses the Nernst-Planck (NP) transport equation to compute steady-state ionic flux in a non-equilibrium system and uses the Local Equilibrium Monte Carlo (LEMC) simulation technique to establish the statistical mechanical relation between the two crucial functions present in the NP equation: the concentration and the electrochemical potential profiles (Boda, D., Gillespie, D., J. Chem. Theor. Comput., 2012 8(3), 824–829). The LEMC method is an adaptation of the Grand Canonical Monte Carlo method to a non-equilibrium situation. We apply the resulting NP+LEMC method to ionic systems, where two reservoirs of electrolytes are separated by a membrane that allows the diffusion of ions through a nanopore. The nanopore can be natural (as the calcium selective Ryanodine Receptor ion channel) or synthetic (as a rectifying bipolar nanopore). We show results for these two systems and demonstrate the effectiveness of the NP+LEMC technique.

2013/2014
Artificial molecular structures forming stable pores in biological membranes may have important applications in the biomedical field and in the field of biotechnology, in particular as sensors. These structures have to meet specific characteristics of size, shape and solubility. In particular, they have to enter the membrane engaging hydrophobic interactions with the phospholipid bilayer and, at the same time, forming a polar conduit for the transport of the ions across the membrane. A molecular structure which meets these features is an amphipathic, rigid and tube-shaped one and, mostly important, long enough to span the entire membrane. The final goal of this thesis work is the design and preparation of structures that would reflect these characteristics obtained by the metal-mediated self-assembly of pyridylporphyrins. In particular to obtain structures long enough to span the membrane the focus was on the design of pyridylporphyrins equipped with complementary hydrogen bonding donor/acceptor moieties and of a polar subunit to increase membrane compatibility. Using transition metal complexes with an adequate geometry these “molecular panels” should self-assemble in metallasquares which, upon hydrogen-bonding driven dimerization in membrane, should form tubular empty structures long enough to span the phospholipid bilayer forming large pores. In the first part of the Thesis work, a versatile and straightforward synthetic strategy for the preparation of a library of amphiphilic trans-A2B2 and trans-A2BC dipyridylporphyrins directly from 5-(4-pyridyl)dipyrromethane has been developed and optimized. The major part of the porphyrins synthesized in this way are new compounds.The library members have been functionalized through different metal catalysed coupling reactions, showing their great potential and versatility towards the different employment which could be addressed, to obtain amphiphilic and dimeric derivatives, in some cases with very good and satisfying yields. The derivatization reactions have been performed on the free base porphyrins and, therefore, it has been necessary to carefully optimize the conditions of the metal catalysed reactions in order to avoid the insertion of the catalyst, or of the co-catalyst, in the porphyrin macrocycle. The functionalities that have been inserted into the dipyridylporphyrins scaffold are hydrogen-bonding complementary donor/acceptor moieties, like uracil and diacylaminopyridine, and an amphiphilic polyether chains. Starting from the porphyrin library and exploiting metal catalysed coupling reaction also three dipyridylporphyrins dimers have been prepared. The target amphiphilic dipyridylporphyrins have been principally utilized in self-assembly reactions exploiting the pyridyl groups present, in particular through the coordination-driven self-assembly approach, with cis-coordinating metal complexes like Re(CO)5Br and trans,cis,cis-[RuCl2(CO)2(DMSO-O)2], leading to the formation of molecular squares together with other kind of metallacyclic species. At the best of our knowledge, this is the first time that the Ru(II) complex have been employed for the self-assembly with trans-dipyridylporphyrins. The porphyrins, the dimers and supramolecules synthesized have been mainly characterized by mean of NMR spectroscopy, in particular through 1H, 13C, 1H-1H COSY, 1H-13C HSQC, 1H-DOSY. The latter technique, being more and more important and utilized in supramolecular chemistry either in the characterization either in the sample purity proof of the compounds, has been in fact thoroughly utilized both to confirm the dimensions in solution of all the molecules synthesized and to give an evidence of their purity. This last feature has been one of the more challenging to face because the sample purity was not so evident just analysing the 1H-NMR spectra due to the possible presence of isomers and conformers. In absence of X-ray spectroscopic and MS spectrometric data, PFG-NMR has been a powerful, helpful and straightforward way to rationalize the high complexity of the resonating signals pattern in these spectra and to confirm the higher molecular dimensions reached as relative to the parent porphyrins. Confirmation of the pyridyl-metal bond formation with the right configuration has come also from IR, UV-Vis and fluorescence emission spectra acquired both for the porphyrins and for the supramolecular metallacycles. Putting together all the data and although in some cases we were not able to unambiguously define the nuclearity of the metallacycle, the supramolecules synthesised have all cyclic and symmetric structure and retain the symmetry of their parent porphyrins.The most representative porphyrins, together with the supramolecular metallacycles have been then tested as transmembrane ion channels utilizing liposomes as model of biological membranes. Preliminary studies on the H+ transport assays have been reported.
Le strutture molecolari artificiali capaci di formare nanopori stabili all’interno di una membrane biologica sono sempre più di ampio interesse, grazie alla possibilità di essere impiegate in campo biomedico e biotecnologico, soprattutto come sensori. Per poter formare nanopori questi sistemi devono soddisfare dei requisiti minimi in termini di forma, dimensioni e solubilità. Essi devono essere in grado di inserirsi facilmente in membrana tramite interazioni idrofobiche e al contempo formare condotti polari che consentano il passaggio degli ioni; quindi una struttura che presenti tali caratteristiche dovrà essere anfifilica, avere una forma allungata, essere abbastanza rigida e, soprattutto, essere sufficientemente lunga da attraversare completamente la membrana. Lo scopo di questo lavoro di tesi è quello di realizzare sistemi che soddisfino queste esigenze sfruttando il metal-mediated self-assembly di piridilporfirine su centri metallici. In particolare, per ottenere strutture sufficientemente lunghe da attraversare completamente il doppio strato fosfolipidico, si è focalizzata l’attenzione sulla realizzazione di piridilporfirine equipaggiate con gruppi accettori e donatori di legami ad idrogeno e con un catena anfifilica che ne aumenti la compatibilità con la membrana. Utilizzando complessi di metalli di transizione con una geometria adeguata questi “pannelli molecolari” dovrebbero assemblarsi a dare metallacicli di forma approssimativamente cubica in grado di dimerizzare in membrana, grazie alla formazione di legami ad idrogeno, formando così strutture tubulari cave sufficientemente lunghe da attraversare completamente la membrana. Nella prima parte della Tesi è stata messa a punto ed ottimizzata una strategia sintetica per ottenere una libreria di derivati anfifilici di trans-A2B2 e trans-A2BC dipiridilporfirine direttamente a partire dal 5-(4-piridil)dipirrometano. La maggior parte delle porfirine sintetizzate in questo modo sono composti nuovi. I membri della libreria sono stati quindi funzionalizzati attraverso reazioni di coupling metallo-catalizzate per ottenere sia derivati anfifilici che dimerici, dimostrando così il loro potenziale e la loro versatilità verso l’utilizzo per diverse applicazioni. Le reazioni di funzionalizzazione sono state condotte sulle porfirine free-base ed è stato dunque necessario ottimizzare accuratamente le condizioni delle reazioni metallo-catalizzate in modo tale da evitare che il catalizzatore, o l’eventuale co-catalizzatore, si potesse inserire nel macrociclo porfirinico. Le funzionalità che sono state inserite nelle dipiridilporfirine sono molecole con gruppi donatori/accettori di legame idrogeno tra di loro complementari , in particolare, derivati dell’uracile e della diacilamminopiridina, e residui anfifilici come catene polieteree. Partendo dalla libreria di porfirine sono anche stati sintetizzati dei dimeri di dipiridilporfirine. Le dipiridilporfirine target sono state principalmente utilizzate in reazioni di auto-assemblaggio sfruttando i gruppi piridinici presenti, in particolare attraverso il metodo coordination-driven self-assembly con complessi metallici cis-coordinanti come Re(CO)5Br e trans,cis,cis-[RuCl2(CO)2(DMSO-O)2], ottenendo la formazione di quadrati molecolari insieme con altre specie metallacicliche. Al meglio delle nostre conoscenze, il complesso di Ru(II) è stato utilizzato per la prima volta per l’auto-assemblaggio con trans-dipiridilporfirine. Le porfirine, i dimeri e gli addotti supramolecolari ottenuti sono stati caratterizzati principalmente tramite spettroscopia NMR, in particolare attraverso 1H, 13C, 1H-1H COSY, 1H-13C HSQC, 1H-DOSY. Quest’ultima tecnica, essendo divenuta sempre più importante in chimica supramolecolare sia per la caratterizzazione sia per provare la purezza dei composti, è stata utilizzata a fondo per confermare le dimensioni in soluzione delle molecole sintetizzate e per avere una prova della purezza dei campioni. Quest’ultimo aspetto è stato uno dei più difficili da affrontare perché non era certo evidente analizzando i soli spettri 1H-NMR acquisiti per la possibile presenza di isomeri e confomeri. In assenza di dati spettroscopici a raggi X e di spettrometria di massa, la tecnica PFG-NMR è stata uno strumento potente, utile e diretto per razionalizzare l’elevata complessità del pattern dei segnali osservato in questi spettri e per confermare le più elevate dimensioni raggiunte da queste molecole relativamente alle porfirine di partenza. Conferma dell’avvenuta formazione dei legami metallo-piridina con la giusta configurazione è venuta anche dai dati spettroscopici IR, UV-Vis e di emissione di fluorescenza, acquisiti per le porfirine così come per i metallacicli supramolecolari. Anche se non è stato possibile in alcuni casi assegnare in maniera non ambigua la nuclearità di queste supramolecole, poiché la geometria molecolare sia di specie a nuclearità [3+3] che [4+4] può essere approssimata dalla medesima sfera, le supramolecole sintetizzate sono specie cicliche e simmetriche e preservano la simmetria molecolare delle specie di partenza.Le porfirine più rappresentative e gli addotti metallaciclici sono stati testati per la loro capacità di formare canali ionici transmembrana utilizzando liposomi come modelli delle membrane biologiche. Gli studi preliminari sull’attività di trasporto di ioni H+ sono riportati nella Tesi.
XXVII Ciclo
1982

DNA nanotechnology has revolutionised our capability to shape and control three-dimensional structures at sub-nanometre length scales. In this thesis, we use DNA to build synthetic membrane-inserting channels. Porphyrin and cholesterol tags serve as membrane anchors to facilitate insertion into the lipid membrane. With atomic force microscopy, confocal imaging and ionic current recordings we characterise our DNA nanochannels that mimic their natural protein-based counterparts in form and function. We find that they exhibit voltage-dependent conductance states. Amongst other architectures, we create the largest man-made pore in a lipid membrane to date approaching the electrical diameter of the nuclear pore complex. Pushing the boundaries on the other end of the spectrum, we demonstrate the ultimately smallest DNA membrane pore made from a single membrane-spanning DNA duplex. Thereby, we proof that ion conduction across lipid membranes does not always require a physical channel. With experiments and MD simulations we show that ions flow through a toroidal pore emerging at the DNA-lipid interface around the duplex. Our DNA pores spanning two orders of magnitude in conductance and molecular weight showcase the rational design of synthetic channels inspired by the diversity of nature - from ion channels to porins.

Le but de cette these est de synthetiser et d'etudier les proprietes pharmacologiques d'activateurs potassiques sensibles a l'atp. Ces activateurs derivent de la 1,2,4-benzothiadiazine-1,1-dioxyde qui comporte un reste sulfonyluree sur differentes positions de cet heterocycle. Dans la premiere partie, nous abordons les proprietes pharmacologiques des canaux potassiques et leur classification, ainsi que celles des composes les plus importants modulant ces canaux. En particulier, nous decrivons les 1,2,4-benzothiadiazine-1,1-dioxydes et les sulfonylurees, dont nous rappelons egalement les methodes de syntheses. La deuxieme partie de la these comporte quatre chapitres: dans le premier nous faisons le point sur les differents schemas de syntheses adoptes pour aboutir aux molecules cibles; le deuxieme chapitre comporte une etude spectrale de quelques composes finaux notamment par rmn du proton et par rmn du carbone 13; le troisieme chapitre comprend l'etude pharmacologique de quelques composes testes sur des anneaux d'aorte de rats; enfin, la partie experimentale decrit les modes operatoires mis en uvre pour preparer les composes intermediaires et cibles ainsi que les methodes de purification et d'identification que nous avons utilisees

Pyridine-based ring systems are heterocycle-structured subunits that are being abundantly employed in drug design, primarily because of their tremendous effect on pharmacological activity, which has resulted in the discovery of various broad-spectrum medicinal compounds. Pyridine derivatives are employed to treat multiple medical illnesses, including prostate cancer, AIDS, tuberculosis, angina, ulcer, arthritis, urinary tract analgesic, Alzheimer’s disease, and cardiovascular diseases. This chapter emphasized the currently available synthetic pyridine derivatives, including nimodipine, ciclopirox, efonidipine, nifedipine, milrinone, and amrinone, effects on cardiac ionic channels and their mechanisms of action for the cure. Pyridine derivatives regulate several voltage-gated ion channel behaviors, including sodium (Nav), calcium (Cav), and potassium (Kv) channels, and are set as a therapeutic approach. Particularly, calcium-channel blockers are the most common action of medicines with a dihydropyridine ring and are often used to treat hypertension and heart-related problems. Finally, this chapter gives the prospects of highly potent bioactive molecules to emphasize the advantages of using pyridine and dihydropyridine in drug design. This chapter discusses pyridine derivatives acting on cardiac ionic channels to combat CVS diseases. The book chapter describes the importance of pyridine derivatives as a novel class of medications for treating cardiovascular disorders.

The power demand is increasing day by day owing to the diminishing of fossil fuel reserves on the globe. To overcome the future energy crises, there is a strong need to fulfill the energy loophole by novel technologies such as triboelectric nanogenerators to harvest miniature resources from renewable natural resources. Here, I discussed the synthesis and fabrication of novel triboelectric nanogenerators (TENGs) using highly reproducible power generators as electropositive surfaces from the monomers of naphthalene tetracarboxylic dianhydride, benzdiene diamine, and sulfonated polyimide (Bno-Spi), and modified nonwoven carbon fibers (Wcf) and polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF) as electronegative TENG electrodes, respectively. Here, novel double characteristic hydrophilic and hydrophobic nano-channels concerned with Bno-Spi films were proposed through contact electrification process through ion and electron transfer by an electron-donor-acceptor complex mechanism. The proposed Bno-Spi-TENG system High triboelectric open circuit voltage 75 V (Voc) and short circuit current 1 μA (Jsc) have been achieved from Bno-Spi-TENGs, in particular, and for SO3H.Bno-Spi-TENG at 6 Hz. Besides that, we used improved knitted woven carbon fiber composite (wcf-COOH), as one of the TENGs to generate a greater open-circuit voltage (Voc), and short circuit current (Isc). Also, I aimed the contact and separation mode TENG which is using spring structure through oxidation of Wcf into Wcf-COOH followed by coupling of aniline through and one-step oxidative polymerization to get woven carbon fiber-polyaniline emraldine salt (Wcf-Pani.Es). The Wcf-PANI.Es composite film (thickness ~ 100 nm) shows the surface resistivity of 0.324 Ω m, and functions as a rubbing surface to produce charges through harvesting of energy using vertical contact-separation mode TENG. The vibrant exchanges of novel Wcf-Pani.Es, and PVDF membrane produced higher Voc of 95 V, and Isc of 180 μA, correspondingly. In specific, Wcf-Pani.Es -TENG is shown an enhancement of 498% of Voc concerning Wcf-COOH-TENG due to the availability of the Pani.Es layer. The novel Bno-Spi-TENGs and Wcf-Pani.Es are the potential candidates for fulfilling the need for improved energy harvesting devices as an alternate substantial choice for contact-separation mode TENGs.

Ion transport in nanoscale channels has recently received increasing attention. Much of that has resulted from experiments that report modulation of ion transport through the protein ion channel, α-hemolysin, due to passage of single biomolecules of DNA or proteins [1]. This has prompted research towards fabricating synthetic nanopores out of inorganic materials and studying biomolecular transport through them [2]. Recently, the synthesis of arrays of silica nanotubes with internal diameters in the range of 5–100 nm and with lengths 1–20 μm was reported [3]. These tubes could potentially allow new ways of detecting and manipulating single biomolecules and new types of devices to control ion transport. Theoretical modeling of ionic distribution and transport in silica nanotubes, 30 nm in diameter and 5 μm long, suggest that when the diameter is smaller than the Debye length, a unipolar solution of counterions is created within the nanotube and the coions are electrostatically repelled [4]. We proposed two different types of devices to use this unipolar nature of solution, i.e. ‘transistor’ and ‘battery’. When the electric potential bias is applied at two ends of a nanotube, ionic current is generated. By locally modifying the surface charge density through a gate electrode, the concentration of counterions can be depleted under the gate and the ionic current can be significantly suppressed. This could form the basis of a unipolar ionic field-effect transistor. By applying the pressure bias instead of electric potential bias, the fluid flow is generated. Because only the counterions are located inside the channel, the streaming current and streaming potential are generated. This could form the basis of an electro-chemo-mechanical battery. In the present study, transport phenomena in nanofluidic channels were investigated and the performance characteristics were evaluated using continuum dynamics.

LiNi0.5Mn1.5O4 is a promising cathode material for lithium-ion batteries with a high-voltage spinel structure. A microwave-assisted chemical co-precipitation method was used to synthesize Y2O3 coated quasi-spheres of LiNi0.5Mn1.5O4. The coating of Y2O3 and subsequent wrapping of quasi-spheres in graphene nanosheets does not alter the volume or promote the formation of unwanted phases. TGA analysis shows high thermal stability in the material. The material has an initial capacity of 133 mAh g−1 at C/10 with a retention of 98% after 100 cycles. In addition, cathode samples show a good capacity of 132 g−1 after 20 cycles at higher temperatures (55 °C). Oxide coatings protect the particles from ionic leaching but limit the electrical conductivity of the materials. However, graphene enhances the conductivity of the synthesized material and wraps active particles in a conductive channel. Due to the synergistic design of the material and the robust manufacturing technique, parasitic reactions are suppressed without affecting the electrical conductivity. To increase their cyclic performance, the suggested material synthesis approach may successfully be applied to various electrode materials.

The analysis and control of transport phenomena in fluidic nanopores and nanochannels is important in applications such as biochemical analysis, power generation and environmental protection. A unique aspect of nanofluidics is that the relevant length scale is comparable to the range of various surface and interfacial forces in liquids (such as electrostatic, van der Waals and steric interactions). Thus, to obtain an adequate description of transport phenomena in nanospace, it is necessary to understand the discreteness of molecules, especially when the size decreases to 2 nm. Micelle-templated mesoporous silicas (MPSs) possess highly ordered structures such as 2D hexagonal and 3D cubic structures and pores within the 2–50 nm range. In particular, 2D hexagonal films that generally have pore channels parallel to the surface plane have been widely synthesized by using various types of template molecules. If the pore channels of such materials are aligned in a certain direction, these materials can be employed for various purposes such as the fabrication of oriented nanowires, optoelectronic devices, recording media, selective separations, and nanofluidic systems. 3D cubic structures give large surface areas and become good candidates for highly efficient catalysts and sensors. Advances in the synthesis, measurement and analysis of nanotubes and nanochannels have allowed ion and liquid transport to be routinely examined and controlled in spaces with dimensions that range from 10 to 100 nm. The ability to now explore transport and adsorption phenomena in confined spaces of around 2 nm offers a range of possibilities. We have investigated several unique transport and adsorption phenomena in mesopores measuring a few nanometers in diameter, including nonlinear I–V curves of ionic current passing through MPS thin films filled with aqueous solutions, humidity-dependent adsorption rate of water into MPS, and the reduction of melting and freezing temperature of water in MPS.