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The colorimetric response of polydiacetylene was observed at the single microdomain level via hyperspectral microscopy, revealing the blue-to-red transition patterns unique to each stimulus.

Polydiacetylene (PDA) is a popular mechanochromic material often used in biosensing. The effect of its headgroup-headgroup interactions on the thermochromism such as pH or salt concentration dependency has been extensively studied before, yet, their effect on mechanochromism at nanoscale is left unstudied. In this work, the nano-friction force microscopy and the fluorescence microscopy were combined to study the effect of pH and ionic strength on the polydiacetylene (PDA) force-sensitivity at the nanoscale. We found that the increase in pH from 5.7 to 8.2 caused an enhancement in the force sensitivity by 8 folds. The elevation of NaCl concentration from 10 mM to 200 mM also made the PDA 5 times more force-sensitive. These results suggest that the PDA force sensitivity at the nanoscale can be conveniently enhanced by “pre-stimulation” with pH or ionic strength.

The antimicrobial peptide double cooperative effect, where the mixture of two major antimicrobial peptides LL-37 and HNP1 kills bacteria more efficiently while minimizing the host damage by suppressing mammalian cell membrane lysis, has garnered attentions due to its potential applications towards efficient and safe antibiotics. However, its mechanism is completely unknown. In this work, we report that the double cooperative effect can be partially recapitulated in synthetic lipid systems just by varying the lipid composition between eukaryotic and E. coli. membranes. Although real cell membranes are so much more complex than just lipids, including e.g. membrane proteins and polysaccharides, our data implicates that one of the main driving forces of the double cooperative effect is a simple lipid-peptide interaction.

Polydiacetylenes (PDAs) are a family of mechanochromic polymers that change color from blue to red and emit fluorescence when exposed to external stimuli, making them extremely popular materials in biosensing. Although several informative reviews on PDA biosensing have been reported in the last few years, their mechanochromism, where external forces induce the color transition, has not been reviewed for a long time. This mini review summarizes recent progress in PDA mechanochromism, with a special focus on the quantitative and nanoscopic data that have emerged in recent years.

A mechanochromic polymer, polydiacetylene, changes color upon ligand binding, being a popular material in biosensing. However, whether it can also detect ligand functions in addition to binding is left understudied. In this work, we report that the polydiacetylene can be used to determine the net charges and the mode of actions (carpet model, toroidal pore model, etc.) of antimicrobial peptides and detergents via EC50 and Hill coefficients from the colorimetric response-dose curves. This opens a potential for high-throughput peptide screening by functions, which is difficult with the conventional methods.

The structural variance of polydiacetylene (PDA) at the nanoscale even under the same fabrication conditions is one of the origins of its poor reproducibility in chemo/biosensing. In this work, we present a spatial map of such structural distributions within a single crystal by taking an advantage of the recent development of hyperspectral microscopy in visible wavelength. Hyperspectral microscopy provides the distribution of absorption spectra at the spatial resolution of the standard optical microscopy. By track-ing the blue-to-red transition via this technique, we found that the heat application leaves a fingerprint in the transition pathways.

We demonstrate the fabrication of carbon nanoribbons with a width of 40 nm based on fixation and pyrolysis of an organic template, lipid nanotubes. To our best knowledge, this is the smallest feature size achieved by pyrolysis of surface-patterned organic templates. Such a pyrolytic carbon nanostructure can be used for electronics and sensing applications in future.

Quantitative and anisotropic mechanochromism of polydiacetylene over nanoscale distances remains unaddressed even after 50 years of extensive research. This is because its anisotropic structure on substrates necessitates the application of both vertical and lateral forces (shear forces) to characterize it, whereas atomic force microscopy, which is the usual technique used to investigate nanoscale forces, is only capable of quantifying vertical forces. In this study, we address this lacuna by utilizing quantitative friction force microscopy that measures lateral forces. Our data confirm that polydiacetylene reacts only to lateral forces

We demonstrate an approach to fabricate a gold nanowire network that presents a macroscopic electrical conductivity based on a lipid nanotube (LNT) template with attached gold nanoparticles. The poor electrical conductivity that we have previously faced was overcome by centrifugation and resuspension of gold nanoparticle solution for removing stabilizing agents, which increased the density of gold nanoparticles on the LNTs. An additional electroless metal plating further enhanced their contacts at nanoscale. Thanks to these procedures, the sheet resistance was improved by 11 orders of magnitude. As a proof of principle, transparent conductive films were fabricated with these gold nanowires, which exhibited sheet resistance of maximum 70 Ω/□ and transmittance of 50–75% in visible light.

In this Communication, we introduce transmembrane anion transport with pnictogen-bonding compounds and compare their characteristics with chalcogen- and halogen-bonding analogues. Tellurium-centered chalcogen bonds are at least as active as antimony-centered pnictogen bonds, whereas iodine-centered halogen bonds are 3 orders of magnitude less active. Irregular voltage-dependent single-channel currents, high gating charges, and efficient dye leakage support for the formation of bulky, membrane-disruptive supramolecular amphiphiles due to “too strong” binding of anions to tris(perfluorophenyl)stibanes. In contrast, the chalcogen-bonding bis(perfluorophenyl)tellanes do not cause leakage and excel as carriers with nanomolar activity, with P(Cl/Na) = 10.4 for anion/cation selectivity and P(Cl/NO3) = 4.5 for anion selectivity. The selectivities are lower with pnictogen-bonding carriers because their membrane-disturbing 3D structure also affects weaker binders (P(Cl/Na) = 2.1, P(Cl/NO3) = 2.5). Their 2D structure, directionality, hydrophobicity, and support from proximal anion−π interactions are suggested to contribute to the unique power of chalcogen bonds to transport anions across lipid bilayer membranes.

LL-37, cleaved from human cathelicidin, and human neutrophil peptide-1 (HNP1) from the defensin family are antimicrobial peptides that are occasionally co-released from neutrophils, which synergistically kill bacteria. We report that this couple presents another type of cooperativity against host eukaryotic cells, in which they antagonistically minimize cytotoxicity by protecting membranes from lysis. Our results describe the potential of the LL-37/HNP1 cooperativity that switches from membrane-destructive to membrane-protective functions, depending on whether the target is an enemy or a host.

Thermochromic temperature of polydiacetylene has been reported to coincide with the melting temperature of its lipidic monomers, indicating that the solid-to-liquid phase transition of monomers is linked to the color change. In this work, we study a hypothesis that peptide-induced chromism is similarly mediated by the lipid phase transition as many antimicrobial peptides are known to modulate the melting temperature of lipids.

The wedge calibration method is the most popular calibration technique in friction force microscopy for converting raw lateral laser deflection signals (in volt) into forces (in newton). Recent trends in nanotribology demand the use of the method at nanonewton (nN) force ranges; however, this method fails at these small forces. The objective of the present work is to identify the reason why the conventional wedge calibration method fails at nN force ranges. We found that the equation used in the model in this method amplifies experimental errors by orders of magnitude only at small setpoints purely due to its mathematical expression. This low tolerance against experimental errors in nanonewton force ranges is the reason for the failure. We identified that the condition, under which the method operates accurately, is adhesion ≪ setpoint. Discovery of this operation range (adhesion ≪ setpoint) is important because performing the calibration under other conditions can wrongly calibrate the system by orders of magnitude.

Green tea polyphenol (−)-epigallocatechin-3-O-gallate (EGCG) has been attributed to the activation of its cell surface sensing receptor 67 kDa laminin receptor (67LR). However, the action of EGCG to activate 67LR remains unknown. Here we show that EGCG undergoes oligomer formation on its surface receptor 67LR.

We have demonstrated colorimetric and fluorescence detection of a peptide, melittin, based on polydiacetylene (PDA) made of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC(8,9)PC). The PDA used in this work has a phosphocholine headgroup, which mimics peptide-cell membrane interactions better than the conventional PDAs with carboxyl headgroups. The dose curve (colorimetric response vs. melittin concentration) showed a half maximum response at the melittin concentration of 0.1 mg ml-1, which is similar to that reported in traditional PDA assays. It suggests that the replacement of the headgroup was achieved without sacrificing the sensitivity. From the dose curve, the Hill coefficient was extracted as αHill = 2.1. The value is in agreement with the results from previous melittin studies with phospholipids, which reflects the benefit of having a biologically relevant headgroup. In addition, we found an unexpectedly slow spectral change when DC(8,9)PC-PDA was incubated with melittin. The origin of the time-dependent signal was studied by combining UV/VIS spectroscopy, fluorescence spectroscopy and dynamic light scattering.

Highlights • There are not sufficient data on viscosity of semi-solid nutrients via the nasogastric tube in vivo. • Tracheal obstruction occurred by reflux and aspiration of semi-solid nutrients through the nasogastric tube • Reflux of semi-solid nutrients is rare, but once it occurs, it can be fatal., Introduction Semi-solid nutrients have several advantages, including reduced cases of diarrhea and aspiration pneumonia, and are usually administered via percutaneous endoscopic gastrostomy owing to its high viscosity. Administering semi-solid nutrients via a nasogastric tube was recently introduced in clinical practice; however, its safety has not been well confirmed. Presentation of case An 82-year-old man with a right occipital hemorrhage and severe diarrhea consulted the nutritional support team. Administrations of semi-solid nutrients (HINE E-GEL®) via the nasogastric tube was initiated, which gradually alleviated his symptoms. Fourteen days after initiation, he suddenly had pulmonary failure owing to a tracheal obstruction caused by the reflux and aspiration of semi-solid nutrients. Intubation and subsequent reflex cough expectorated sputum with gel-form particles, which quickly stabilized his pulmonary condition. After this, his hospital course was stable, and he was referred to another hospital for further rehabilitation. Discussion Semi-solid nutrients administered via the nasogastric tube have different ingredients compared with those administered via percutaneous endoscopic gastrostomy. HINE E-GEL®, for example, contains pectin and calcium phosphate that changes from liquid to semi-solid inside the stomach via chemical reactions under acidic conditions. Data on the viscosity of HINE E-GEL® in vivo are insufficient. Uncertainty regarding the form and viscosity of HINE E-GEL® inside the stomach complicates clinical practice. Conclusions Although semi-solid nutrients have several advantages, including reduced diarrhea and gastroesophageal reflux, evidence on semi-solid nutrients via the nasogastric tube is insufficient. It should be noted that semi-solid nutrient reflux can be more fatal than liquid nutrients.

Horizontal black lipid membranes (BLMs) enable optical microscopy to be combined with the electrophysiological measurements for studying ion channels, peptide pores, and ionophores. However, a careful literature review reveals that simultaneous fluorescence and electrical recordings in horizontal BLMs have been rarely reported for an unclear reason, whereas many works employ bright-field microscopy instead of fluorescence microscopy or perform fluorescence imaging and electrical measurements one after another separately without truly exploiting the advantage of the combined setup. In this work, the major causes related to the simultaneous electrical and fluorescence recordings in horizontal BLMs are identified, and several solutions to counteract the issue are also proposed.

The detection limits of impedance biosensors are dictated by the presence of background nonspecific binding, yet almost all the detection limits reported in the literature are determined using a clean buffer solution without confronting this real challenge. In this work, the authors employed the simplest “differential” impedance biosensor, composed of poly-l-lysine-polyethylene glycol-biotin-coated gold electrodes for the detection of streptavidin in the presence of 0.1% fetal calf serum, and studied the effect of the nonspecific binding on the performance of the differential impedance biosensing. The lowest streptavidin concentration detected by the system (5 μg/ml) was 1 order of magnitude higher (worse) than that from a previously demonstrated impedance biosensor where avidin was detected in the absence of background proteins. Interestingly, the origin of the differential signal was not due to the electrochemical properties of streptavidin itself but was that of the serum, where the coverage of the electrode by streptavidin indirectly modulated the electrical signal by suppressing the accessibility of the serum to the electrode.

We performed a detailed deconvolution analysis of ATR-FTIR peaks of a common diacetylene, 10,12-tricosadiynoic acid (TRCDA) during the polymerization and the blue-to-red transition. Based on the analysis and the solvent dependence on the IR signals, we found that the triple peak from C C stretching mode that has been previously suspected as a consequence of Fermi resonance is rather associated with the macromolecular assembly of TRCDA. Besides these C C triple peaks, we found that the background in the region increased during the UV exposure due to the C C signals from polymers. In addition, the anisotropic compression during polymerization was also detected, which supports the proposed interpretation of X-ray data reported previously. These results are the benefits from the deconvolution analysis.

A high-throughput approach to fabricate gold nanowires on surfaces with a lipid nanotube template is demonstrated. Streptavidin-coated gold nanoparticles are attached to the biotin-tagged lipid nanotubes. After the chemical fixation, the samples are dried and treated with oxygen plasma to remove the organic template and connect the particles. The created nanowires are characterized by cryo-transmission electron microscopy, atomic force microscopy, and electrical measurements.

The design, synthesis, and evaluation of multifunctional dithieno[3,2‐b;2′,3′‐d]thiophene (DTT) trimers is described. Twisted push‐push‐pull or donor‐donor‐acceptor (DDA) trimers composed of one DTT acceptor and two DTT donors show strong mechanochromism in lipid bilayer membranes. Red shifts in excitation rather than emission and fluorescence recovery with increasing membrane order are consistent with planarization of the twisted, extra‐long mechanophores in the ground state. The complementary pull‐pull‐pull or AAA trimers with deep σ holes all along the scaffold are not mechanochromic in membranes but excel with submicromolar anion transport activity. Anion transport along membrane‐spanning strings of chalcogen‐bond donors is unprecedented and completes previous results on transmembrane cascades that operate with equally unorthodox interactions such as halogen bonds and anion‐π interactions.

We report a platform based on lateral nano-black lipid membranes (nano-BLMs), where electrical measurements and fluorescence microscopy setup are combined, for the calibration of di-4-ANEPPS, a common voltage sensitive dye (VSD). The advantage of this setup is (1) its flexibility in the choice of lipids and applied voltages, (2) its high stability that enables a high voltage (500 mV) application and long-time measurements and (3) its fluorescence microscopy readout, which can be directly correlated with other fluorescence microscopy experiments using VSDs (e.g. membrane potential measurements in living cells). Using this setup, we observed that the calibration curve of di-4-ANEPPS is strongly dependent on the net electric charge of the lipids. The developed setup can be used to calibrate VSDs in different lipid environments in order to better understand their fundamental voltage-sensing mechanism in the future.

Tunneling nanotubes (TNTs) have become a major topic of interest as a form of intercellular communication due to their recent discovery. However, research on this subject has often suffered from a lack of controllability in the generation of the nanotubular connections. In this work, we demonstrate a simplified approach to selectively create a direct nanotubular connection between eukaryotic cells by manually manipulating self-assembling lipid nanotubes (LNTs) from inverted hexagonal-phase lipid blocks. The technique requires minimal instrumentation for creating the LNT connection between cells compared to conventional approaches. Based on the diffusion of fluorescent lipids from LNTs into cell membranes (D = 0.032 ± 0.003 μm2 s−1), the probability of observing membrane fusion between LNTs and cell membranes was estimated as 30%. Among these cell–LNT junctions the resulting structure is open-ended roughly 75% of the time, as evidenced from observations of the diffusion of a water-soluble dye between two cells connected with this nanotubular structure.

We hypothesized that ABFs can be functionalized with liposomes, thus allowing these micromachines to per-form biological or biomedical tasks in a remotely con-trolled fashion. To test this hypothesis fl uorescently labeled liposomes and calcein-loaded liposomes were adsorbed on the surface of ABFs. The adsorption of liposomes on the ABFs was confi rmed by quartz crystal microbalance with dissipation monitoring (QCM-D) and fl uorescence recovery after photobleaching (FRAP). The liposome-functionalized ABFs were then placed in contact with cells in vitro and the uptake of calcein (a model water soluble drug) by cells was monitored using fl uorescence microscopy. The fabrication of ABFs was followed as described ear-lier by Tottori et al.

(−)-Epigallocatechin-3-O-gallate (EGCG), a polyphenol in green tea, induces apoptosis in acute myeloid leukemia (AML) cells without affecting normal cells. In this study, we observed that cGMP acts as a cell death mediator of the EGCG-induced anti-AML effect through acid sphingomyelinase activation. EGCG activated the Akt/eNOS axis, a well-known mechanism in vascular cGMP upregulation. We also observed that a major cGMP negative regulator, phosphodiesterase 5, was overexpressed in AML cells, and PDE5 inhibitor, an anti-erectile dysfunction drug, synergistically enhanced the anti-AML effect of EGCG. This combination regimen killed AML cells via overexpressed 67-kDa laminin receptors.

Polydiacetylene (PDA) is a conductive polymer that has mechanochromism. When the polymer is exposed to mechanical stresses, change in temperature (thermochromism), pH (ionochromism), and so forth, the structural perturbation can be seen by the change in its color. Although it presents interesting electrical and optical properties, the relationship between these signals has rarely been investigated. We studied the correlation between the electrical conductivity and the absorption spectra of PDA. Upon UV irradiation, PDA absorption spectra presented a blue shift, which coincided with the decrease in the electrical conductivity.

EGCG [(−)-epigallocatechin-3-O-gallate], the major polyphenol of green tea, has cancer chemopreventive and chemotherapeutic activities. EGCG selectively inhibits cell growth and induces apoptosis in cancer cells without adversely affecting normal cells; however, the underlying molecular mechanism in vivo is unclear. In the present study, we show that EGCG-induced apoptotic activity is attributed to a lipid-raft clustering mediated through 67LR (67 kDa laminin receptor) that is significantly elevated in MM (multiple myeloma) cells relative to normal peripheral blood mononuclear cells, and that aSMase (acid sphingomyelinase) is critical for the lipid-raft clustering and the apoptotic cell death induced by EGCG. We also found that EGCG induces aSMase translocation to the plasma membrane and PKCδ (protein kinase Cδ) phosphorylation at Ser664, which was necessary for aSMase/ceramide signalling via 67LR. Additionally, orally administered EGCG activated PKCδ and aSMase in a murine MM xenograft model. These results elucidate a novel cell-death pathway triggered by EGCG for the specific killing of MM cells.

The resistivity ρ(PEM) of polyelectrolyte multilayers (PEMs), PEI(PSS/PAH)(24), PEI(PGA/PAH)(12), PEI(HA/PLL)(12) and PEI(PSS/PLL)(12), in a free-hanging configuration was estimated combining electrochemical impedance spectroscopy (EIS) and atomic force microscopic (AFM) images. Surprisingly, the obtained value of several kΩcm is at least 6 orders of magnitude lower than that reported previously, where the resistivity was determined in the conventional PEM-on-electrode system. The significant discrepancy indicates the unexpectedly low electrical PEM resistance in the absence of redox-active ions and the sensitivity limitation in the conventional system.

LNTs are unique 3D structures made only of safe and abundant biomaterials by self-assembly. The current bottleneck for developing applications using LNTs is the lack of an easy technique to pattern them on substrates. We report a method to free-draw single lipid nanotube (LNT) patterns in any shape on surfaces with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) that takes an inverted hexagonal (HII) phase. We used pre-self-assembled LNTs or HII lipid blocks as a lipid reservoir from which new LNTs were pulled by applying a point load with a micromanipulator. The extreme simplicity of our technique originates from the fundamental nature of DOPE lipids that prefer a HII phase, while all the conventional approaches use PC lipids that form a lamellar phase. By adjusting the surface properties with polyelectrolyte multilayers, the created single LNT objects are able to remain adhered to the surface for over a week. Importantly, it could be shown that two vesicles loaded with caged fluorescent molecules were able to fuse well with a LNT, enabling diffusive transport of uncaged fluorescent molecules from one vesicle to the other.

We observe an adiabatic transport phenomena of electrons in valley-splitting quantum Hall edge channels for the first time using a high-mobility Si/SiGe two-dimensional electron system. We find that the scattering event between the valley-splitting edge channels is suppressed over a distance of ∼ 5 μ m , which is surprisingly longer than that expected from the valley-splitting energy gap in Si.

Inspired by flagellar propulsion of bacterial such as E. coli, artificial bacterial flagella (ABFs) are magnetic swimming microrobots with helical shapes. ABFs can perform precise three-dimensional (3D) navigation in liquids under low-strength rotating magnetic fields making them attractive tools for drug delivery applications. Further functionalization of these swimming microrobots is necessary to optimize their performance of biomedical tasks. We report here for the first time the successful functionalization of titanium-coated ABFs with temperature-sensitive dipalmitoylphosphatidylcholine (DPPC) liposomes. Adsorption of intact liposomes on titanium was assessed using quartz crystal microbalance with dissipation monitoring (QCM-D). The adsorption of fluorescently labeled liposomes on the surface of ABFs was confirmed with confocal laser scanning microscopy (CLSM) images. Functionalized ABFs (f-ABFs) can be loaded with both hydrophilic and hydrophobic drugs, and controlled drug release triggered by temperature. ABFs have a great potential to be used in targeted and controlled drug delivery and for in vivo sensing.

The 67-kDa laminin receptor (67LR) is a laminin-binding protein overexpressed in various types of cancer, including bile duct carcinoma, colorectal carcinoma, cervical cancer, and breast carcinoma. 67LR plays a vital role in growth and metastasis of tumor cells and resistance to chemotherapy. Here, we show that 67LR functions as a cancer-specific death receptor. In this cell death receptor pathway, cGMP initiated cancer-specific cell death by activating the PKCδ/acid sphingomyelinase (PKCδ/ASM) pathway. Furthermore, upregulation of cGMP was a rate-determining process of 67LR-dependent cell death induced by the green tea polyphenol (-)-epigallocatechin-3-O-gallate (EGCG), a natural ligand of 67LR. We found that phosphodiesterase 5 (PDE5), a negative regulator of cGMP, was abnormally expressed in multiple cancers and attenuated 67LR-mediated cell death. Vardenafil, a PDE5 inhibitor that is used to treat erectile dysfunction, significantly potentiated the EGCG-activated 67LR-dependent apoptosis without affecting normal cells and prolonged the survival time in a mouse xenograft model. These results suggest that PDE5 inhibitors could be used to elevate cGMP levels to induce 67LR-mediated, cancer-specific cell death.

Several nanoporous platforms were functionalized with pH-responsive poly(methacrylic acid) (PMAA) brushes using surface-initiated atom transfer radical polymerization (SI-ATRP). The growth of the PMAA brush and its pH-responsive behavior from the nanoporous platforms were confirmed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). The swelling behavior of the pH-responsive PMAA brushes grafted only from the nanopore walls was investigated by AFM in aqueous liquid environment with pH values of 4 and 8. AFM images displayed open nanopores at pH 4 and closed ones at pH 8, which rationalizes their use as gating platforms. Ion conductivity across the nanopores was investigated with current–voltage measurements at various pH values. Enhanced higher resistance across the nanopores was observed in a neutral polymer brush state (lower pH values) and lower resistance when the brush was charged (higher pH values). By adding a fluorescent dye in an environment of pH 4 or pH 8 at one side of the PMAA-brush functionalized nanopore array chips, diffusion across the nanopores was followed. These experiments displayed faster diffusion rates of the fluorescent molecules at pH 4 (PMAA neutral state, open pores) and slower diffusion at pH 8 (PMAA charged state, closed pores) showing the potential of this technology toward nanoscale valve applications.

Surface-bound self-assembled lipid nanotubes (LNTs) made of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) were used to visualize the contractile activity of spreading cells. The interaction of cells with LNTs resulted in the nucleation of new nanotubes, directed toward the cell center, from existing ones. This process depended on cell generated forces and required acto-myosin mediated contractility. The dynamics of de novo generation of LNTs upon cell spreading was captured using optical microscopy on fluorescently labeled nanotubes and revealed characteristic fingerprints for different cell types such as fibroblasts, endothelial and melanoma cells. Additionally, the method was applied to detect the effect of a specific inhibitor on the generation of cellular forces. The mechanism of the LNT-cell interaction and the potential applications are discussed.

A simultaneous optical waveguide lightmode spectroscopy (OWLS) and electrochemical impedance spectroscopy (EIS) measurement was carried out for the investigation of a supported lipid bilayer and its interactions with a pore-forming peptide, melittin. It was achieved only after the optimization of the ITO coating on the waveguide to increase the electrical sensitivity and the functionalization of the waveguide with a polyelectrolyte to form a lipid bilayer over the ITO surface. The combined system enabled monitoring of melittin pore activities in a wider range of melittin concentrations than either technique alone (1 μg/ml

Conventional lipid-tube formation is based on either a tube phase of certain lipids or the shape transformation of lamellar structures by applying a point load. In the present study, lipid blocks in inverted hexagonal phase made of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) were shown to protrude lipid nanotubes upon a fluid-dynamic flow on polyelectrolyte-functionalized surfaces in physiological buffer solution. The outer diameter of the tubes is 19.1 ± 4.5 nm and their lengths are up to several hundred micrometers. The method described enables the alignment and patterning of lipid nanotubes into various (including curvy) shapes with a microfluidic system.

A procedure based on freezing and thawing was developed to induce the rupture of adsorbed lipid vesicles on solid surfaces into supported lipid bilayers (SLBs). The SLB assembly exploits the phase transition of both lipids and water during freezing. It enables SLB formation independent of the type of substrates and lipids as long as the vesicles spontaneously adsorb onto the surface. The created SLB is a single bilayer, and has a diffusion coefficient of (0.6–4) × 10−8 cm2 s−1 on TiO2, which is in the same range as the SLBs formed by conventional techniques. The presented approach has the advantages of both the Langmuir–Blodgett method (the versatility in the selection of lipids and substrates) and vesicle fusion (self-assembly) at the same time.

Inverted hexagonal blocks of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) lipid adsorbed on a polyethyleneimine (PEI)-coated surface in deionized water transformed its shape upon the application of an electric field, forming lipid objects in a variety of shapes (e.g. lines with a width of 10–50 μm). The phenomenon was driven by the electrophoresis, because the zwitterionic lipid, DOPE turned out to be highly negatively charged in deionized water. The interaction between DOPE and the PEI surface stabilized the system, assuring a lifetime over several weeks for the formed structures after the electric field was switched off. The free-drawing of microscopic objects (lines, crosses, and jelly fish) was also achieved by controlling the direction of the lipid movement with the field direction.