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Cationic amphiphilic polymers have been a platform to create new antimicrobial materials that act by disrupting bacterial cell membranes. While activity characterization and chemical optimization have been done in numerous studies, there remains a gap in our knowledge on the antimicrobial mechanisms of the polymers, which is needed to connect their chemical structures and biological activities. To that end, we used a single giant unilamellar vesicle (GUV) method to identify the membrane-disrupting mechanism of methacrylate random copolymers. The copolymers consist of random sequences of aminoethyl methacrylate and methyl (MMA) or butyl (BMA) methacrylate, with low molecular weights of 1600-2100 g·mol-1. GUVs consisting of an 8:2 mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), sodium salt (POPG) and those with only 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were prepared to mimic the bacterial (Escherichia coli) or mammalian membranes, respectively. The disruption of bacteria and mammalian cell membrane-mimetic lipid bilayers in GUVs reflected the antimicrobial and hemolytic activities of the copolymers, suggesting that the copolymers act by disrupting cell membranes. The copolymer with BMA formed pores in the lipid bilayer, while that with MMA caused GUVs to burst. Therefore, we propose that the mechanism is inherent to the chemical identity or properties of hydrophobic groups. The copolymer with MMA showed characteristic sigmoid curves of the time course of GUV burst. We propose a new kinetic model with a positive feedback loop in the insertion of the polymer chains in the lipid bilayer. The novel finding of alkyl-dependent membrane-disrupting mechanisms will provide a new insight into the role of hydrophobic groups in the optimization strategy for antimicrobial activity and selectivity.

To address the emerging issue of drug-resistant bacteria, membrane-active synthetic polymers have been designed and developed to mimic host-defense antimicrobial peptides (AMPs) as antibiotic alternatives. In this study, we investigated the domain formation induced by synthetic polymer mimics of AMPs using model membranes to elucidate the biophysical principles that govern their membrane-active mechanisms. To that end, lipid vesicles mimicking Escherichia coli (E. coli) membrane were prepared using an 8:2 (molar ratio) mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), sodium salt (POPG). Our studies using differential scanning calorimetry (DSC) and fluorescence microscopy indicated that cationic amphiphilic methacrylate random copolymers induced the phase separation to form POPE- or POPG-rich domains. A rhodamine-labeled polymer also showed the binding to separated domains in the membrane. Based on these results, we propose the mechanism that the copolymers induce domain formation by clustering of anionic POPG lipids similar to natural AMPs. In addition, the time-course of polymer binding to the GUV membrane was sigmoidal, suggesting the positive feedback loop in the membrane binding. We also hypothesize that this cooperative binding of the polymer is driven by the domain formation. This study demonstrates the potential of the amphiphilic copolymers to modulate the lipid organization of cell membranes, which may provide a new strategy to design membrane-active antimicrobial agents.

Realization of molecular quantum cellular automata (QCA), a promising architecture for molecular computing through current-free processes, requires improved understanding and application of mixed-valence (MV) molecules. In this report, we present an electrostatic approach to creating MV subspecies through internalizing opposite charges in close proximity to MV ionic moieties. This approach is demonstrated by unsymmetrically attaching a charge-responsive boron substituent to a well-known organometallic MV complex, biferrocenium. Guest anions (CN- and F- ) bind to the Lewis acidic boron center, leading to unusual blue-shifts of the intervalence charge-transfer (IVCT) bands. To the best of our knowledge, this is the first reported example of a zwitterionic MV series in which the degree of positive charge delocalization can be varied by changing the bound anions, and serves to clarify the interplay between IVCT parameters. The key underlying factor is the variable zero-level energy difference in the MV states. This work provides new insight into imbuing MV molecules with external charge-responsiveness, a prerequisite of molecular QCA techniques.

Dynamic aspects of molecular recognition at the air-water interface have been investigated using a monolayer of a steroid cyclophane SC(OH) which consists of the rigid 1,6,20,25-tetraaza[6.1.6.1]paracyclophane ring, connected to four steroid moieties (cholic acid) through flexible -lysine spacers. An aqueous fluorescent guest (TNS) can be reversibly captured by SC(OH) with a variation in the accompanying fluorescence emission upon compression and expansion of the SC(OH) monolayer. Tight capture, by compression of the monolayer to a high surface pressure, efficiently enhances fluorescence intensity because of suppression of formation of the non-emissive state. On the other hand, rapid motion of the reversible cavity formation by a high rate of compression and expansion of the monolayer results in better reproducibility in the fluorescence change than that obtained under a slower motion, which can be explained by the suppression of unfavorable structural relaxation within the monolayer structures. This result has connotations for the development of novel molecular devices and machines that operate through mechanically driven molecular recognition.

In this study, we report synthesis of a new series of mixed-valence (MV) complexes having intervalence charge transfer (IVCT) energies variable from the first to the third telecommunication window....

Phenylalanine ester-introduced palladium(II) and platinum(II) complexes were synthesized. Taking advantage of the formation of Schiff bases by amino acids as an intermediate, the pyridylimine moiety coordinated to a metal center. Single crystals of each complex were obtained successfully, and their molecular structures were clarified in detail. The Pd(II) complex showed remarkable cytotoxicity compared to the Pt(II) complex.

5,10,15,20-Tetrakis(4-(α-d-mannopyranosylthio)-2,3,5,6-tetrafluorophenyl)-2,3-(methano(N-methyl)iminomethano)chlorin (H2TFPC-SMan) has been prepared and characterized by 1H and 19F NMR and UV-vis spectroscopies, MALDI-TOF mass spectrometry, and elemental analysis. H2TFPC-SMan generates singlet oxygen (1O2) upon light irradiation. The value of the relative magnitude of the 1O2-generating ability of H2TFPC-SMan is comparable to that of 5,10,15,20-tetrakis(4-(β-d-glucopyranosylthio)-2,3,5,6-tetrafluorophenyl)-2,3-(methano(N-methyl)iminomethano)chlorin (H2TFPC-SGlc). The dark and photocytotoxicity of H2TFPC-SMan and H2TFPC-SGlc were tested in HeLa cells. These compounds showed no cytotoxicity in the dark. Upon photoirradiation, these compounds killed almost all of the cells in the region of a 1 to 2 µM concentration. The photocytotoxicity of the compounds completely disappeared in the concentration region of 0 to 0.1 µM. The photocytotoxicity of H2TFPC-SMan is significantly higher than that of H2TFPC-SGlc in ...

There is a growing interest in the use of lipid bilayer nanodiscs for various biochemical and biomedical applications. Among the different types of nanodiscs, the unique features of synthetic polymer-based nanodiscs have attracted additional interest. A styrene-maleic acid (SMA) copolymer demonstrated to form lipid nanodiscs has been used for structural biology related studies on membrane proteins. However, the application of SMA polymer based lipid nanodiscs is limited because of the strong absorption of the aromatic group interfering with various experimental measurements. Thus, there is considerable interest in the development of other molecular frameworks for the formation of polymer-based lipid nanodiscs. In this study, we report the first synthesis and characterization of a library of polymethacrylate random copolymers as alternatives to SMA polymer. In addition, we experimentally demonstrate the ability of these polymers to form lipid bilayer nanodiscs through the fragmentation of lipid vesicles by means of light scattering, electron microscopy, differential scanning calorimetry, and solution and solid-state NMR experiments. We further demonstrate a unique application of the newly developed polymer for kinetics and structural characterization of the aggregation of human islet amyloid polypeptide (also known as amylin) within the lipid bilayer of the polymer nanodiscs using thioflavin-T-based fluorescence and circular dichroism experiments. Our results demonstrate that the reported new styrene-free polymers can be used in high-throughput biophysical experiments. Therefore, we expect that the new polymer nanodiscs will be valuable in the structural studies of amyloid proteins and membrane proteins by various biophysical techniques.

A novel liposomal nanocomposite, Au@PIL-cerasome, with biocompatibility and conductivity was fabricated via the self-assembly of cerasomes and gold nanoparticles (AuNPs) stabilized by poly(ionic liquid)s (PILs). The surface charge, morphology and chemical composition of the nanocomposites were characterized by the zeta potential, UV–vis, TEM, SEM and EDS. The nanocomposites exhibited structural stability directly on the surface of solid electrodes, without fusion. Electrochemical impedance experiments demonstrated that the nanocomposites had an enhanced conductivity compared with unmodified cerasomes. Horseradish peroxidase (HRP), as a reporter, was immobilized on the nanocomposites without denaturation or inactivation. The direct electron transfer of HRP was achieved, and the HRP/Au@PIL-cerasome/GCE exhibited an amplified current and improved electrocatalytic activity. Activity towards H2O2 displayed a linear range over 10–70 μM and a detection limit of 3.3 μM. Activity towards NO2− displayed linear ranges over 1–5 mM and 5–1280 mM, and the limit of detection was 0.11 mM. In addition, the electrode was stable and reproducible, with 6% RSD. Such multi-component liposomal nanocomposites with an enhanced electrical performance pave a better way for building novel and straightforward 3D stereo biomimetic electrochemical platforms and even molecular communication systems to investigate information transduction between cells.

In this study, we report the generation of new mixed-valence (MV) subspecies with charge-separated (CS) characters from an unsymmetrical acceptor–donor–donor (A–D–D) triad. The triad was synthesized by attaching a dimesitylboryl group (A) to a D–D conjugate that consisted of triarylamine (NAr3) units. The MV radical cation, obtained by chemical oxidation of the triad, exhibited a strong intervalence charge transfer (IVCT) absorption derived from the bis(NAr3)•+ moiety in the near-IR region. The charge-separated MV (CSMV) state, obtained by photoexcitation of the triad, caused a blue shift in IVCT energy in the femtosecond transient absorption spectra, reflecting a bias of positive charge distributions to the D end site. This resulted from increased electron density at the A site and restructuring of the central D site from NAr3 to NAr2 sites. Interestingly, any shift in the IVCT energy that was caused by the polarity of the solvent was minimal, reflecting the unique characteristics of the CSMV state. Thes...

Background/Aim: Resistance against cisplatin is a problem for the success of gastric cancer chemotherapy. Herein, we evaluated the antitumor effect of a new aminosugar-conjugated, mono-functional platinum complex (Pt-Oqn), which forms a single covalent bond with DNA. Materials and Methods: We compared the cytotoxicity of Pt-Oqn to that of cisplatin (CDDP), oxaliplatin (L-OHP) and carboplatin (CBDCA). We also compared Pt-Oqn and cisplatin for DNA double-strand breaks based on phosphorylated histone H2AX levels in cancer cells and antitumor effects in xenograft models. Results: The resistance factor (RF) for Pt-Oqn was low among the four drugs, indicating the potential of Pt-Oqn for overcoming CDDP-induced resistance. In MKN45-R cells, γ-H2AX protein increased following treatment with Pt-Oqn, but not with cisplatin. Finally, Pt-Oqn, but not cisplatin, showed significant antitumor effects in MKN45-R xenografts. Conclusion: This new aminosugar-conjugated platinum complex is a promising candidate agent for overcoming the drug resistance of cisplatin-resistant stomach cancer.

// Hirotada Nishie 1 , Hiromi Kataoka 1 , Shigenobu Yano 2 , Jun-ichi Kikuchi 2 , Noriyuki Hayashi 1 , Atsushi Narumi 3 , Akihiro Nomoto 4 , Eiji Kubota 1 , Takashi Joh 1 1 Departments of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan 2 Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan 3 Department of Organic Materials Science, Graduate School of Organic Materials Science, Yamagata University, Yamagata, Yonezawa 992-8510, Japan 4 Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Nakaku, Sakai, Osaka 599-8531, Japan Correspondence to: Hiromi Kataoka, email: hkataoka@med.nagoya-cu.ac.jp Keywords: oligosaccharide-conjugated chlorin, Warburg effect, glycoconjugated chlorin, photodynamic therapy, photodynamic diagnosis Received: August 21, 2016 Accepted: September 23, 2016 Published: September 30, 2016 ABSTRACT Photodynamic therapy (PDT) exploits light interactions and photosensitizers to induce cytotoxic reactive oxygen species. Photodynamic diagnosis (PDD) uses the phenomenon of photosensitizer emitting fluorescence to distinguish some tumors from normal tissue. The standard photosensitizer used for PDD is 5-aminolevulinic acid (5-ALA), although it is not entirely satisfactory. We previously reported glucose-conjugated chlorin (G-chlorin) as a more effective photosensitizer than another widely used photosensitizer, talaporfin sodium (TS); however, G-chlorin is hydrophobic. We synthesized oligosaccharide-conjugated chlorin (O-chlorin) with improved water-solubility. We report herein on its accumulation and cytotoxicity. O-chlorin was synthesized and examined for solubility. Flow cytometric analysis was performed to evaluate O-chlorin accumulation in cancer cells. To evaluate the intracellular localization of photosensitizer, cells were stained with O-chlorin and organelle-specific fluorescent probes. We then measured the in vitro fluorescence of various photosensitizers and the half-maximal inhibitory concentrations to evaluate effects in PDD and PDT, respectively. Xenograft tumor models were established, and antitumor and visibility effects were analyzed. O-chlorin was first shown to be hydrophilic. Flow cytometry then revealed a 20- to 40-times higher accumulation of O-chlorin in cancer cells than of TS, and a 7- to 23-times greater fluorescence than 5-ALA. In vitro , the cytotoxicity of O-chlorin PDT was stronger than that of TS PDT, and O-chlorin tended to accumulate in lysosomes. In vivo , O-chlorin showed the best effect in PDT and PDD compared to other photosensitizers. O-chlorin was hydrophilic and showed excellent tumor accumulation and fluorescence. O-chlorin is promising as a next-generation bifunctional photosensitizer candidate for both PDT and PDD.

A new Pd complex Pd(tBu2bpy)(FcC) 2Fc (FcC = 4-ferrocenylcatecholato, tBu2bpy = 4,4′-di-tert-butyl-2,2′-dipyridyl) was synthesized and characterized using 1H and 13C NMR spectroscopy, and ESI-MS. Electrochemical analysis of 2Fc using cyclic voltammetry in CH2Cl2/nBu4NPF6 revealed two well-defined, quasi-reversible waves assigned to the sequential oxidation of the Pd(tBu2bpy)(C) and ferrocene (Fc) moieties. The potential splitting between the waves (519 mV) indicated that there was an electronic interaction between both moieties. The one-electron-oxidized species of 2Fc was investigated using DFT calculations and UV–vis–NIR spectroscopy, and its charge-transfer property was compared with that of Pt(tBu2bpy)(FcC) 1Fc, FcV (4-ferrocenylveratrole), and FcA (4-ferrocenylcatechol bis(acetate)). 2Fc+ was Fc+-centered, rather than semiquinone-ligand centered, and exhibited an ICT transition band from to the catecholate to the Fc+ moiety in the NIR region. The electronic coupling (HAB) value of 2Fc+ (790 cm−1) was...

The solid-state structures of 1′,1‴-biferrocenediboronic acid (1) were elucidated by X-ray crystallography, to obtain insight into controlling the structures of hydrogen-bonded (H-bonded) assemblies from a functional organobimetallic building block. Four solvated crystal forms of 1 were newly obtained by recrystallization under different solvent conditions. The dioxane-, pyridine-, and pyrimidine-solvated crystals (Forms III to V) involved chain-like 1D H-bonded networks of 1. The 1D chains of 1 were capped with solvent molecules with lateral H-bonds. The pyrazine-solvated crystals (Form VI) involved 1D chains of 1, which were connected by pyrazine molecules with lateral H-bonds to afford sheet-like 2D networks. The suitable bidentate H-bond acceptor was found to transform 1D chains into 2D networks. Two crystal forms of 1′,1‴-biferroceniumdiboronic acid (1+) were also prepared and investigated the geometry of the H-bonded assemblies and the valence states of 1+. The mixed-valence (MV) cation 1+ forms 1D chains (Form VII) and discrete dimers (Form VIII) with triiodide anions in the valence-detrapped and trapped states, respectively. This study demonstrates the usefulness of the boronic acid-based method to obtain MV supramolecular structures in the solid state.

Photoactive molecules with the frameworks of chlorin and/or porphyrin possessing four perfluorinated aromatic rings were conjugated with maltotriose (Mal3) via the nucleophilic aromatic substitution reaction and subsequent deprotection reaction of the oligosaccharide moieties. The resulting oligosaccharide-conjugated molecules are ultimately improved as compared to the previously reported monosaccharide-counterparts in terms of water-solubility. In particular, a water-soluble chlorin derivative surrounded by four Mal3 molecules showed an excellent biocompatibility, strong photoabsorption in the longer wavelength regions, and a very high photocytotoxicity. Thus, the present synthetic route combined with the use of an oligosaccharide was shown to be a straightforward strategy to develop a third generation photosensitizer for photodynamic therapy (PDT).

Cerasomes are a novel organic–inorganic hybrid material composed of spherical lipid bilayer vesicles with an internal aqueous compartment, which are similar to liposomes formed from phospholipids, with an inorganic silicate framework covering the vesicular surface. In this research, an anionic cerasome formed from N,N-dihexadecyl-N′-[(3-triethoxysilyl)propyl]urea was successfully prepared, and the cerasomes were characterized by scanning electron microscopy (SEM), behaving as a spherical-like structure. An electrochemical platform was constructed using a combination of the cerasomes and cholesterol oxidase (ChOx) on a glassy carbon electrode. Ultraviolet-visible (UV-vis) spectroscopy was used to monitor the assembly process and the electrochemical impedance spectroscopy (EIS) results demonstrated that ChOx had been successfully immobilized. The obtained enzyme-modified electrode exhibited both the effective direct electron transfer between the enzyme and electrode surface and the excellent electrochemical catalytic activity towards cholesterol with a wide linear range from 5.0 × 10−6 to 3.0 × 10−3 mol L−1 and a low detection limit 1.7 × 10−6 mol L−1 (S/N 3). The excellent catalytic performance of the modified electrode is attributed to the good biocompatibility of the cerasomes, which can provide a soft and morphologically stable interface for enzymatic immobilization, allowing the enzyme to retain its catalytic activity, along with their specific affinity (Km 0.139 mmol L−1) for water-insoluble cholesterol. The results indicate that cerasomes are useful as a platform for electrochemical sensing of cholesterol and have the potential to immobilize enzymes for bioelectrochemical applications.

Anionic cerasomes, which consist of a liposomal lipid bilayer and a ceramic surface, were used as a soft interface for the construction of an integrated modified electrode to achieve the transmission of chemical information from a redox enzyme through electrical signals. The morphological properties of the cerasomes were systematically compared with those of two structural analogues, namely, liposomes and silica nanoparticles. The results indicated that the cerasomes combined the advantages of liposomes and silica nanoparticles. The lipid bilayer gave excellent biocompatibility, as in the case of liposomes, and high structural stability, similar to that of silica nanoparticles, was derived from the silicate framework on the cerasome surface. The performance at the electrochemical interface created by means of a combination of cerasomes and horseradish peroxidase on a glassy carbon electrode was much better than those achieved with liposomes or silica nanoparticles instead of cerasomes. The potential use of cerasomes in the construction of supramolecular devices for mediator-free biosensing was evaluated.

A molecular assembly of a hydrophobized metallophthalocyanine derivative embedded in a cerasome, an organic–inorganic hybrid vesicle with a lipid bilayer and silica surface, was a potent catalyst for aerobic oxidation of thioglycol. The catalytic activity was higher than those in hexadecyl 2-hydroxy-3-chloropropyl phosphate vesicles, sodium dodecylsulfate micelles, ethanol, and benzene.

The visible-light-driven dechlorination system without the use of a noble metal has been developed. We screened the combination of cobalt catalysts having square-planar monoanionic ligands (hydrophobic B12 model complex 1/imine-oxime type complex 2) and typical red dyes (Rose Bengal 3/Rhodamine B 4/Nile Red 5) for the construction of a dehalogenation system via a noble-metal-free and visible-light-driven process. The combination of the hydrophobic B12 model complex 1 and Rose Bengal 3 exhibited the highest catalytic activity to 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) to form the monodechlorinated compound, 1,1-bis(4-chlorophenyl)-2,2-dichloroethane, as the major product. The prolonged photocatalysis of DDT by the B12–Rose Bengal system afforded the tri-dechlorinated compound, trans-4,4′-dichlorostilbene, as the major product. Furthermore, we investigated the mechanism of the dehalogenation cycle using various methods such as UV–vis spectroscopy and laser flash photolysis. Finally, we clarified the advantage of using the hydrophobic B12 model complex 1 as an electron acceptor as well as a cobalt catalyst in the organic dye-involved photocatalysis.

It was found that the exchange method for the preparation of lipid-membrane-incorporated guest molecules was applicable not only to fullerenes but also to other hydrophobic molecules such as azobenzene and stilbene. Advantages of this method are that the long-term stability of lipid-membrane-incorporated azobenzene solution and the maximum ratio of [stilbene]/[lipid] were higher than those prepared by the classical method, which we call the ‘premixing method’. Photoisomerisations of these photochromic guest molecules in the lipid membranes maintained the morphology of liposomes., This file includes Electronic Supplementary Information., This work was supported by JSPS KAKENHI a Grant-in-Aid for Scientific Research (B) (Grant No. 25288037), a Grant-in-Aid for Challenging Exploratory Research (Grant Nos. 24655128 and 25650053) and a Grant-in-Aid for Young Scientists (A) (Grant No. 24681028).

The target compound of this study is the macrocyclic tetraferrocenyl boronate complex CP2C, which has two types of metal connections (i.e., FeII–CpCp–FeII and FeII–CpBO2C5H8O2BCp–FeII (Cp = cyclopentadienyl)) in the finite structure (C = 1′,1‴-biferrocenediboronic acid, P = pentaerythritol). The electrochemical behavior of CP2C in dichloromethane was compared with that of the related boronate complexes APA and BP2B, having FeII–CpBO2C5H8O2BCp–FeII, and Cester, having FeII–CpCp–FeII. The effects of the counteranion of the supporting electrolyte on potential splitting revealed that CP2C exhibits an intrabiferrocenyl through-bond interaction through the CpCp ligand, as well as an interbiferrocenyl through-space interaction across the CpBO2C5H8O2BCp ligand. Chemical oxidation of CP2C with AgSbF6 produced the one- and two-electron-oxidized species CP2C+ and CP2C2+, which exhibit intervalence charge transfer transition bands through the CpCp ligand in the near-infrared region, giving one and two valence isomers...

An organic–inorganic hybrid liposome, cerasome, was utilized as a new gene carrier for solid-phase transfection. The cerasome-modified glass substrate exhibited an increased transfection performanc...

Monomeric cyt c has been reported to bind to the mitochondrial membrane by electrostatic and hydrophobic interactions with anionic phospholipids. We have previously shown that domain-swapped oligomeric cyt c retains the secondary structure of the monomer, and its surface possesses a larger area and more charges compared to the monomer. However, the effect of oligomerization of cyt c on cells has yet to be revealed. Herein, we investigated the interaction of oligomeric cyt c with anionic phospholipid-containing vesicles and the outer membrane of HeLa cells. Oligomeric cyt c interacted more strongly than monomeric cyt c with anionic phospholipid-containing vesicles and the outer membrane of HeLa cells. Oligomeric cyt c induced lateral phase separation of lipids in LUVs and GUVs, thereby leading to membrane disruption, whereas monomeric cyt c did not. Morphological changes in HeLa cells resulted from interaction with oligomeric cyt c, but little from interaction with the monomer. These results show that domain-swapped oligomeric proteins might exhibit properties different to those of monomer in cell systems.

In this paper, we report a method for the construction of multi-ferrocenyl spiroborate assemblies from discrete mono- and di-ferrocenyl complexes. To prepare the building blocks for the spiroborate assemblies, 4-ferrocenylveratrole (1) and 4,5-diferrocenylveratrole (3) were first synthesized by Negishi cross-coupling between ferrocene and the corresponding aryl halides. Compounds 1 and 3 were characterized by NMR and UV-vis spectroscopies and electrochemical methods, namely cyclic voltammetry and differential pulse voltammetry. The potential splittings of 167 and 263 mV for the oxidations of the two ferrocenyl groups of 3 in CH2Cl2-n-Bu4NPF6 and n-Bu4NB(C6F5)4, together with the presence of an intervalence charge-transfer transition of 3(+) in the NIR region, indicate a strong inter-ferrocenyl interaction through the ortho connection in the veratrole bridge. The treatment of 1 and 3 with BBr3, followed by complexation with B(OH)3 in the presence of KOH, afforded potassium salts of di- and tetra-ferrocenyl spiroborate assemblies, K2 and K4, respectively. The spiroborate assemblies K2 and K4 were characterized by NMR and UV-vis spectroscopies, ESI-MS, and electrochemical methods. K2 exhibited a potential splitting value of 302 mV in DMF-n-Bu4NPF6, indicating electronic interactions over the boron center. K4 exhibited four one-electron-oxidation waves in DMF-n-Bu4NPF6 and n-Bu4NB(C6F5)4; the one-electron-oxidized species 4 is thermodynamically more stable than 4(+) and 4(2+). The overall E(1/2)(1)-E(1/2)(4) spread for K4 is 201 mV larger than the E(1/2)(1)-E(1/2)(2) splitting for 3 in DMF-n-Bu4NPF6, indicating that the spiroborate link between diferrocenyl units led to electronic interactions over the boron center.

To obtain direct evidence for the fullerene-exchange reactions from the γ-cyclodextrin cavities to the lipid membranes following the addition of a C70·γ-cyclodextrin complex, we monitored the dynamic behaviours of the giant unilamellar vesicles. A number of C70 aggregates generated in the lipid membranes moved about vigorously.

1',1'''-Biferrocenediboronic acid () was synthesized from 1',1'''-dibromobiferrocene by a typical procedure of converting Br to B(OH)2 groups in 76% yield and identified by (1)H-, (13)C- and (11)B-NMR and ESI-MS. X-ray diffraction (XRD) studies showed that, in non-solvated crystals (Form I), the new organobimetallic building block formed 1D hydrogen-bonded networks (i.e., chain) with octaatomic rings composed of the neighbouring two molecules. In solvated crystals with a composition of ()3(THF)2 (Form II), exists in two conformers (Conformers A and B) with respect to the rotation of the CpB(OH)2 moieties relative to the Cp rings of the fulvalenide moieties; Conformer A formed 1D hydrogen-bonded networks laterally hydrogen-bonding with THF molecules while Conformer B formed a new planar hydrogen-bonded motif involving four B(OH)2 groups and stepwise laminated networks of the planar motif. A macrocyclic tetraferrocenyl boronate ester was synthesized by cyclocondensation between and pentaerythritol in 33% yield and identified by (1)H-, (13)C- and (11)B-NMR, ESI-MS and XRD. In electrochemical measurements, the cyclocondensed compound exhibited four defined reversible waves with a total spread of 756 mV in CH2Cl2 containing n-Bu4NBArF4 (ArF = 3,5-bis(trifluoromethyl)phenyl), displaying both intra- and inter-biferrocenyl interactions.

Cyclodextrins (CDxs) have been selectively deuterated using a Ru/C-catalyzed H-D exchange reaction in D2O. The structures of the deuterated CDxs barely changed and their (1)H NMR spectra became very simple, which made it possible for the deuterated CDxs to be applied to the analysis of CDx complexes. Furthermore, the deuterated CDxs allowed for the existence of the equilibrium between free and complexed CDx to be confirmed, even at rt.

We have evaluated the photodynamic activities of C60 derivative·γ-cyclodextrin (γ-CDx) complexes and demonstrated that they were significantly higher than those of the pristine C60 and C70·γ-CDx complexes under photoirradiation at long wavelengths (610-720 nm), which represent the optimal wavelengths for photodynamic therapy (PDT). In particular, the cationic C60 derivative·γ-CDx complex had the highest photodynamic ability because the complex possessed the ability to generate high levels of (1)O2 and provided a higher level of intracellular uptake. The photodynamic activity of this complex was greater than that of photofrin, which is the most widely used of the known clinical photosensitizers. These findings therefore provide a significant level of information toward the optimization of molecular design strategies for the synthesis of fullerene derivatives for PDT.

The visible-light-driven dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was carried out in the presence of a hydrophobic vitamin B12 , heptamethyl cobyrinate perchlorate and Rhodamine B . DDT was successfully dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD) as the mono-dechlorinated product upon visible light irradiation with a tungsten lamp (λ > 440 nm). Upon prolonged visible light irradiation to DDT, DDMU (1-chloro-2,2-bis(4-chlorophenyl)ethylene), DDMS (1-chloro-2,2-bis(4-chlorophenyl)ethane) and DCS (trans-4,4′-dichlorostilbene) were obtained as the di- and tri-dechlorinated products. The use of the photostable organic sensitizer enabled prolonged photocatalysis via a noble-metal-free process. The vitamin B12 derivative was replaced by an imine/oxime-type cobalt complex although the cobalt complex system showed a lower catalytic activity than the B12 derivative system. The dechlorination mechanism in the B12 -Rhodamin B system was investigated by various methods such as UV-vis absorption and fluorescence quenching.

We investigated the interaction of branched polyethyleneimine (PEI) with anionic vesicles formed with 1,2-dioleoyl- sn -glycero-3-phospho- l -serine (DOPS) by spectroscopic measurements and microscopic observations. PEI induced the fusion of the vesicles only over a specific concentration range, which was found to be below the transition of vesicular zeta-potential from negative to positive value. Above the concentration window of membrane fusion, charge inversion of DOPS vesicles due to the further adsorption of PEI onto the surface of vesicle, inhibited the membrane fusion events. The PEI with low molecular weight induced the membrane fusion in a wider range of concentration than high molecular weight PEIs. Our results suggest that the mechanism of PEI interaction with the lipids depends on the molecular weight and stoichiometry of the polycation to negatively charged lipids.

CUB domain-containing protein-1 (CDCP1) is a trans-membrane protein predominantly expressed in various cancer cells and involved in tumor progression. CDCP1 is phosphorylated at tyrosine residues in the intracellular domain by Src family kinases and recruits PKCδ to the plasma membrane through tyrosine phosphorylation-dependent association with the C2 domain of PKCδ, which in turn induces a survival signal in an anchorage-independent condition. In this study, we used our cell-free screening system to identify a small compound, glycoconjugated palladium complex (Pd-Oqn), which significantly inhibited the interaction between the C2 domain of PKCδ and phosphorylated CDCP1. Immunoprecipitation assays demonstrated that Pd-Oqn hindered the intercellular interaction of phosphorylated CDCP1 with PKCδ and also suppressed the phosphorylation of PKCδ but not that of ERK or AKT. In addition, Pd-Oqn inhibited the colony formation of gastric adenocarcinoma 44As3 cells in soft agar as well as their invasion. In mouse models, Pd-Oqn markedly reduced the peritoneal dissemination of gastric adenocarcinoma cells and the tumor growth of pancreatic cancer orthotopic xenografts. These results suggest that the novel compound Pd-Oqn reduces tumor metastasis and growth by inhibiting the association between CDCP1 and PKCδ, thus potentially representing a promising candidate among therapeutic reagents targeting protein-protein interaction.

A novel fluorescent nanohybrid was fabricated via the self-assembly of semiconductive quantum dots (QDs) on biocompatible cerasomes. The nanohybrid (denoted as QDs-cerasome) was used as an electrode material for visible protein immobilization and bioelectrochemistry. The morphology and surface properties of the QDs-cerasome hybrid were characterized by transmission electron microscopies, atomic force microscopies and zeta potential measurements. Because the QDs-cerasome hybrid possessed a positive charge in aqueous solution, it could be used as a matrix to immobilize negatively charged hemoglobin (Hb) via electrostatic interaction. Ultraviolet–visible spectroscopy demonstrated that Hb was immobilized on the hybrid matrix without denaturation. The fluorescence of the QDs-cerasome was quenched as Hb was immobilized, indicating that the protein immobilization process could be visibly detected. Compared with protein electrodes constructed using a single-component material, including Hb-QDs/GC and Hb-cerasome/GC electrodes, the Hb-QDs-cerasome/GC electrode not only realized enhanced direct electrochemistry, but also displayed higher sensitivity and a wider linear range toward the detection of hydrogen peroxide because of the synergistic effect of the QDs and cerasomes. The experimental results demonstrate that this fluorescent multicomponent hybrid material provides a novel and effective platform to immobilize a redox protein to realize direct electrochemistry. As such, this hybrid shows promise for application in third-generation electrochemical biosensors.

A nanosensory membrane device was constructed for detecting liposome fusion through changes in an enzymatic activity. Inspired by a biological signal transduction system, the device design involved functionalized liposomal membranes prepared by self-assembly of the following molecular components: a synthetic peptide lipid and a phospholipid as matrix membrane components, a Schiff’s base of pyridoxal 5’-phosphate with phosphatidylethanolamine as a thermo-responsive artificial receptor, NADH-dependent L-lactate dehydrogenase as a signal amplifier, and Cu2+ ion as a signal mediator between the receptor and enzyme. The enzymatic activity of the membrane device was adjustable by changing the matrix lipid composition, reflecting the thermotropic phase transition behavior of the lipid membranes, which in turn controlled receptor binding affinity toward the enzyme-inhibiting mediator species. When an effective fusogen anionic polymer was added to these cationic liposomes, membrane fusion occurred, and the functionalized liposomal membranes responded with changes in enzymatic activity, thus serving as an effective nanosensory device for liposome fusion detection.

A supramolecular system that can activate an enzyme through photo-isomerization was constructed by using a liposomal membrane scaffold. The design of the system was inspired by natural signal transduction systems, in which enzymes amplify external signals to control signal transduction pathways. The liposomal membrane, which provided a scaffold for the system, was prepared by self-assembly of a photoresponsive receptor and a cationic synthetic lipid. NADH-dependent L-lactate dehydrogenase, the signal amplifier, was immobilized on the liposomal surface by electrostatic interactions. Recognition of photonic signals by the membrane-bound receptor induced photo-isomerization, which significantly altered the receptor's metal-binding affinity. The response to the photonic signal was transmitted to the enzyme by Cu(2+) ions. The enzyme amplified the chemical information through a catalytic reaction to generate the intended output signal.

Lipid-membrane-incorporating C(60) and C(70) (LMIC(60) and LMIC(70)) were prepared by the fullerene-exchange reaction from the γ-cyclodextrin cavity to vesicles (we call this method the "exchange method"). An advantage of this method is that the ratios of [C(60)]/[lipids] and [C(70)]/[lipids] can be arbitrarily controlled by adjusting the ratios of the fullerenes and liposome. The maximum ratio (30 mol%) obtained was approximately 14 and 100 times higher than those achieved for LMIC(60) and LMIC(70) , respectively, that were prepared by the classical method, which we call the "premixing method" (dissolving lipids and C(60) or C(70) in chloroform, followed by concentration and extraction with water). Furthermore, the stabilities and photodynamic activities of the LMIC(60) and LMIC(70) solutions prepared by the exchange method were shown to be much higher than those prepared by the premixing method. That is, the exchange method was found to be superior to the premixing method as a preparative method of LMIC(60) and LMIC(70) for applications in photomedical and photomaterials chemistry.

Molecular communication is a novel communication paradigm inspired by information processing in biological systems using molecules as information medium. In this study, we achieved the selective propagation of transport vesicles which is an essential technique to establish a molecular communication system using artificial cells. The hybridisation of DNA was employed to conduct a signal-induced delivery of transport vesicles from a sender to a receiver vesicle formed with phospholipids. Oligonucleotide lipids each with a different single-stranded DNA, which acts as recognition tags, were embedded in the sender, receiver and transport vesicles. The addition of a DNA signal with a complementary sequence to connect two oligonucleotide lipids induced the assembly of two types of large unilamellar vesicles as well as recombination of the vesicles. In addition, the selective delivery of transport vesicles between sender and receiver giant vesicles is discussed, based on the results of fluorescence microscopic ob...

Biomimetic cerasome has drawn much attention as a novel drug delivery system because its atomic layer of polyorganosiloxane surface imparts higher morphological stability than conventional liposomes and its liposomal bilayer structure reduces the overall rigidity and density greatly compared to silica nanoparticles. But, the issues about the interactions between cerasomes and biological systems have not been addressed as far as we could find. Herein, we reported cellular uptake of cerasomes and their biological effects toward human umbilical vein endothelial cells (HUVECs) compared with silica nanoparticles. The results indicated that the uptake of cerasomes by HUVECs was a concentration-, time-, and energy-dependent process and occurred probably through a process of clathrin-mediated endocytosis, which resulted in rearrangement of the cell cytoskeleton. Cerasomes affected different aspects of cell function to a smaller extent than silica nanoparticles, including cell proliferation, cell cycle, cell apoptosis, endogenous ROS level and pro-inflammatory molecular expression. In a word, cerasomes are more biocompatible than silica nanoparticles due to the incorporation of the liposomal architecture into cerasomes. The preliminary data will assist in the further development of new cerasome-based delivery systems.

Many researchers have successfully solubilised single-walled carbon nanotubes (SWNTs) to overcome the disadvantage of their insolubility, which restricts their applications. Control of self-assembly behaviour such as precipitation or re-solubilisation of SWNTs may provide new possibilities, for example, for purification of as-grown SWNTs and preparation of SWNT devices. In this study, SWNTs were solubilised through the interaction between SWNT surfaces and a copper complex with a water-soluble phenanthroline derivative as ligand in an aqueous solution. Furthermore, precipitation of SWNTs was controlled by changing the solubilisation ability through structural conversion of the copper complex by reduction and ligand exchange reactions. The procedure that was developed has the advantage that it gives precipitated SWNTs that are free from residual solubilising agents.

Spontaneous division of lipid bilayer vesicles was observed for giant vesicles formed by a phospholipid mixture containing a nonbilayer-forming lipid, i.e., a nonionic peptide lipid with a quinoyl ...

Two steroid cyclophanes, having individually L-lysine and L-aspartate residues as connector units interposed between a 1,6,20,25-tetraaza[6.1.6.1]paracylophane skeleton and four cholate moieties, were designed and synthesized. The cationic steroid cyclophane, having L-lysine residues, binds anionic and non-ionic guests very efficiently, while it has no capacity to bind a guest with a positive charge in aqueous solution. On the other hand, the anionic steroid cyclophane, bearing L-aspartate residues, shows good binding affinity toward hydrophobic guests in aqueous solution regardless of their charged states. Aggregate morphology of the cationic and anionic peptide lipids, involving an L-alanine residue interposed between a charged head moiety and a hydrophobic double-chain segment, in the sonicated vesicular state was not perturbed significantly upon formation of hybrid assemblies with the steroid cyclophanes in 2.5 mol%. Even though the anionic bilayer vesicle interacts only weakly with anionic guests, the corresponding hybrid assembly formed with the cationic steroid cyclophane is capable of marked molecular recognition of anionic guests, along with shape-sensitive discrimination, through electrostatic and hydrophobic interactions in aqueous solution. In a similar manner, the cationic bilayer membrane alone is incapable of binding a cationic guest. However, the guest-binding ability is not much enhanced in the presence of the anionic steroid cyclophane. Consequently, the cationic steroid cyclophane can act as an efficient cell-surface receptor model for anionic guests while the anionic steroid cyclophane is not a good receptor model when both are embedded in bilayer membranes.

Molecular communication is a bio-inspired communication paradigm using molecules as information carriers. The molecular communication system includes propagation of information carrier molecules between a molecular sender and a molecular receiver and followed by amplification of the information at the receiver. In this article, we built an example molecular communication system using a gemini peptide lipid as a molecular switch. The molecular switch embedded in the lipid bilayer membranes exhibited photoresponsive recognition behaviour towards metal ions, such as Cu2+ and Zn2+, to control propagation of molecular capsules formed by small liposomes to a giant liposomal receiver. In addition, the molecular switch acted as an artificial receptor in the receiver, receiving a photonic signal to communicate with an enzyme as a signal amplifier by using Cu2+ ion as a mediator between the receptor and the amplifier.

A 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP)-deposited ITO electrode as a sensor of nucleotides using photocurrent change was prepared. The TPyP-deposited ITO electrode could repeatedly detect nucleotides having concentrations of the microM order by a decrease in the photocurrent.

[70]Fullerene (C(70)) encapsulated into a surface-cross-linked liposome, a so-called cerasome, was prepared by an exchange reaction incorporating C(70)gamma-cyclodextrin complexes into lipid membranes. Fullerene exchange in a cerasome-incorporated C(70) (CIC(70)), as well as in a lipid-membrane-incorporated C(70) (LMIC(70)), was completed within 1 min with stirring at 25 degrees C. CIC(70) was more resistant to lysis than LMIC(70) towards lysing agents such as surfactants. Furthermore, the photodynamic activity of CIC(70) in HeLa cells was similar to that of LMIC(70), indicating that C(70) can act as a photosensitizing drug (PS) without release from cerasome membranes. Thus, in contrast with general drug-delivery systems (DDSs), which require the drug to be released from the interior of liposomes, carriers for PSs for use in photodynamic therapy (PDT) do not necessarily need to release the drug. These results indicate that DDSs with high morphological stability can increase the residence time in blood and achieves tumor-selective drug delivery by the enhanced permeability and retention (EPR) effect.

A novel fluorescent sensor responsive to local viscosity in the lipid bilayer membranes was designed and synthesized. The sensor changes its fluorescence intensity reflecting the local viscosity of its surrounding medium. The fluorescence measurement showed that the sensor is capable of discriminating between different phase states of lipid bilayer. In addition, the sensor visualized liquid-ordered microdomains on giant vesicles in terms of the microviscosity with a simple fluorescence technique.

An azobenzene-modified cholesterol was designed and synthesized for photo-induced domain transformation in lipid bilayer membranes. Upon UV-light irradiation, the cholesterol derivative changes the conformation through photoisomerization of the azobenzene moiety from trans- to cis-form. The photoisomerization effectively occurred both in liquid-ordered (Lo) and liquid-disordered (Ld) phases. Phase-contrast and fluorescence microscopic observation revealed that photoisomerization of the azobenzene-modified cholesterol induced the shape transformation of giant unilamellar vesicle (GUV) and the reorganization of Lo domain structure. Such a photo-induced transformation of lipid domain gave two different pathways dependent on the lipid composition of GUV; disappearance of the Lo domain or appearance of a small Ld domain with in the Lo domain.