Amphiphilic Β-cyclodextrin Research Articles

Aided-efflux and high production of β-amyrin realized by β-cyclodextrin in situ synthesized on surface of Saccharomyces cerevisiae.

As a plant-derived pentacyclic triterpenoid, β-amyrin has been heterogeneously synthesized in Saccharomyces cerevisiae. However, β-amyrin is intracellularly produced in a lower gram scale using recombinant S. cerevisiae, which limits the industrial applications. Although many strategies have been proven to be effective to improve the production of β-amyrin, the intracellularly accumulation is still a challenge in reaching higher titer and simplifying the extraction process. To solve this problem, the amphiphilic β-cyclodextrin (β-CD) has been previously employed to aid the efflux of β-amyrin out of the cells. Nevertheless, the supplemented β-CD in the medium is not consistent with β-amyrin synthesis and has the disadvantage of rather high cost. Therefore, an aided-efflux system based on in situ synthesis of β-CD was developed in this study to enhance the biosynthesis of β-amyrin and its efflux. The in situ synthesis of β-CD was started from starch by the surface displayed cyclodextrin glycosyltransferase (CGTase) on yeast cells. As a result, the synthesized β-CD could capture 16% of the intracellular β-amyrin and improve the total production by 77%. Furthermore, more strategies including inducing system remodeling, precursor supply enhancement, two-phase fermentation and lipid synthesis regulation were employed. Finally, the production of β-amyrin was increased to 73 mg/L in shake flask, 31 folds higher than the original strain, containing 31 mg/L of extracellular β-amyrin. Overall, this work provides novel strategies for the aided-efflux of natural products with high hydrophobicity in engineered S. cerevisiae.

Functional group polarity-modulated formation of liquid crystals of amphiphilic cyclodextrins

Polyesterified amphiphilic β-cyclodextrin derivatives bearing functionalized tetraethylene glycols showed excellent abilities to self-assemble into stable hexagonal columnar mesophases with 1D ion conducting channels.

Amphiphilic hypercrosslinked β-cyclodextrin polymers with rigid networks for efficient acteoside separation

In this study, a series of amphiphilic hypercrosslinked β-cyclodextrin polymers (AHβ-CDPs) were synthesized by the hypercrosslinked strategy for acteoside (ACT) separation. Amphiphilic β-cyclodextrin (β-CD) had rigid ring structures, which constructed the rigid networks of AHβ-CDPs. AHβ-CDPs with rigid networks improved adsorption performance for two reasons. On one hand, the hydrophilic ACT was preferentially adsorbed on the hydrophilic outer surface of β-CD, and the hydrophobic molecules were encapsulated in the hydrophobic cavity, improving adsorption selectivity. On the other hand, the constructed rigid networks of AHβ-CDPs with affinity groups provided large specific surface area (1281.16 m2/g) and abundant pore structure, increasing additional transport pathways and affinity sites for enhancing adsorption capacity. The experimental results showed the as-prepared AHβ-CDPs-4 had the highest adsorption capacity of 288.36 ± 2.12 mg/g and the selectivity of 4.36 ± 0.11. Therefore, amphiphilic hypercrosslinked adsorbents with rigid networks had potential application for bioactive components separation from natural products.

A β-Cyclodextrin-Based Nanoparticle with Very High Transfection Efficiency Unveils siRNA-Activated TLR3 Responses in Human Prostate Cancer Cells

Synthetic double-stranded small interfering RNAs (siRNAs) mimic interference RNAs (RNAi) and can bind target mRNAs with a high degree of specificity, leading to selective knockdown of the proteins they encode. However, siRNAs are very labile and must be both protected and transported by nanoparticles to be efficiently delivered into cells. In this work, we used a Janus-type polycationic amphiphilic β-cyclodextrin derivative to efficiently transfect siRNAs targeting mRNAs encoding mitogen-activated protein kinase (p42-MAPK) or Ras homolog enriched in brain (Rheb) into different cancer cell lines as well as astrocytes. We took advantage of this high transfection efficiency to simultaneously knock down p42-MAPK and Rheb to boost docetaxel (DTX)-mediated toxicity in two human prostate cancer cell lines (LNCaP and PC3). We found that double knockdown of p42-MAPK and Rheb increased DTX-toxicity in LNCaP but not in PC3 cells. However, we also observed the same effect when scramble siRNA was used, therefore pointing to an off-target effect. Indeed, we found that the siRNA we used in this work induced toll-like receptor 3 activation, leading to β-interferon production and caspase activation. We believe that this mechanism could be very useful as a general strategy to elicit an immune response against prostate cancer cells.

KLVFF oligopeptide-decorated amphiphilic cyclodextrin nanomagnets for selective amyloid beta recognition and fishing

Recognition and capture of amyloid beta (Aβ) is a challenging task for the early diagnosis of neurodegenerative disorders, such as Alzheimer’s disease. Here, we report a novel KLVFF-modified nanomagnet based on magnetic nanoparticles (MNP) covered with a non-ionic amphiphilic β-cyclodextrin (SC16OH) and decorated with KLVFF oligopeptide for the self-recognition of the homologous amino-acids sequence of Aβ to collect Aβ (1–42) peptide from aqueous samples.MNP@SC16OH and MNP@SC16OH/Ada-Pep nanoassemblies were fully characterized by complementary techniques both as solid powders and in aqueous dispersions. Single domain MNP@SC16OH/Ada-Pep nanomagnets of 20–40 nm were observed by TEM analysis. DLS and ζ-potential measurements revealed that MNP@SC16OH nanoassemblies owned in aqueous dispersion a hydrodynamic radius of about 150 nm, which was unaffected by Ada-Pep decoration, while the negative ζ-potential of MNP@SC16OH (−40 mV) became less negative (−30 mV) in MNP@SC16OH/Ada-Pep, confirming the exposition of positively charged KLVFF on nanomagnets surface.The ability of MNP@SC16OH/Ada-Pep to recruit Aβ (1–42) in aqueous solution was evaluated by MALDI-TOF and compared with the ineffectiveness of undecorated MNP@SC16OH and VFLKF scrambled peptide-decorated nanoassemblies (MNP@SC16OH/Ada-scPep), pointing out the selectivity of KLVFF-decorated nanohybrid towards Aβ (1–42). Finally, the property of nanomagnets to extract Aβ in conditioned medium of cells over-producing Aβ peptides was investigated as proof of concept of effectiveness of these nanomaterials as potential diagnostic tools.

Co-delivery of doxorubicin and conferone by novel pH-responsive \u03b2-cyclodextrin grafted micelles triggers apoptosis of metastatic human breast cancer cells

Adjuvant-aided combination chemotherapy is one of the most effective ways of cancer treatment by overcoming the multidrug resistance (MDR) and reducing the side-effects of anticancer drugs. In this study, Conferone (Conf) was used as an adjuvant in combination with Doxorubicin (Dox) for inducing apoptosis to MDA-MB-231 cells. Herein, the novel biodegradable amphiphilic β-cyclodextrin grafted poly maleate-co-PLGA was synthesized by thiol-ene addition and ring-opening process. Micelles obtained from the novel copolymer showed exceptional properties such as small size of around 34.5 nm, CMC of 0.1 μg/mL, and cell internalization of around 100% at 30 min. These novel engineered micelles were used for combination delivery of doxorubicin-conferone with high encapsulation efficiency of near 100% for both drugs. Our results show that combination delivery of Dox and Conf to MDA-MB-231 cells had synergistic effects (CI < 1). According to cell cycle and Annexin-V apoptosis analysis, Dox-Conf loaded micelle significantly induce tumor cell apoptosis (more than 98% of cells population showed apoptosis at IC50 = 0.259 μg/mL). RT-PCR and western-blot tests show that Dox-Conf loaded βCD-g-PMA-co-PLGA micelle induced apoptosis via intrinsic pathway. Therefore, the unique design of multi-functional pH-sensitive micelles open a new perspective for the development of nanomedicine for combination chemo-adjuvant therapy against malignant cancer.

Thiolated amphiphilic β-cyclodextrin-decorated gold colloids: Synthesis, supramolecular nanoassemblies and controlled release of dopamine

We report a hybrid nanoassembly based on gold colloids decorated with a new thiolated amphiphilic cyclodextrin complexing dopamine (AuNPs@SC16SH/DA). The novel amphiphilic β-cyclodextrin SC16SH, bearing on average one thiol group at the end of an oligoethylene glycol chain per CyD unit, was obtained in a multi-step synthesis and fully characterized by NMR spectroscopy and MALDI analysis. The AuNPs@SC16SH hybrid assembly was prepared by mixing AuNPs and SC16SH in aqueous solution and investigated by UV/Vis and TEM measurements. The AuNPs@SC16SH/DA supramolecular assembly, bearing both thiol-stabilized gold nanoparticles and the neurotransmitter dopamine, has been conceived as stimuli-responsive delivery system able to control the release of dopamine upon proper stimuli. Two redox functionalities (i.e. the Au-S bond and the redox behaviour of dopamine) have been exploited to detach SC16SH/DA complex from the AuNPs@SC16SH/DA progenitor platform, using dithiothreitol (DTT), and to detect the complex by cyclic voltammetry (CV). Following, dopamine was finally released from the SC16SH/DA assembly upon treatment with Brij® S20 and the free dopamine was monitored by CV. Overall, our hybrid nanoassemblies turned out to be able to release dopamine, upon combined action of redox and digestion agents in medium emulating biological environment.

Polycationic cyclodextrin nanoparticles induce apoptosis and affect antitumoral activity in HepG2 cell line: An evaluation at the molecular level

Hepatocellular carcinoma (HCC) is a highly metastatic primary liver cancer generating molecular alterations that end up escaping the apoptotic machinery and conferring multidrug resistance. Targeted medicines with increased and selective cytotoxicity and minimal drug resistance are essential for the treatment of HCC. In this study, a self-assembled polycationic (PC) amphiphilic β-cyclodextrin (βCDC6) nanoparticle formulation was characterized and its efficacy over HCC cell line HepG2 was evaluated in terms of cytotoxicity, apoptotic potential, chemosensitivity and mitochondrial balance utilizing biochemical, gene expression and proteomic approaches without encapsulating an anti-neoplastic agent. Blank PC βCDC6 exerted an anti-proliferative effect on 3D multicellular HepG2 spheroid tumors. These nanoparticles were able to trigger apoptosis proved by caspase 3/7 activity, gene expression and flow cytometry studies. The subjection of PC restored the chemosensitivity of HepG2 cells by suppressing the function of p-glycoprotein. The proteomic studies with Q-TOF LC/MS revealed 73 proteins that are aberrantly encoded after cells were treated with the blank PC. Metabolomic analysis further confirmed the shift in certain biological pathways. Thus, we confirmed that the hepatocellular carcinoma-targeting βCDC6 PC nanoparticles induce apoptosis, lower the rate of cell proliferation, hinder multidrug resistance and they are convenient carriers for eventual therapeutic administrations in HCC patients.

Multicharge β-cyclodextrin supramolecular assembly for ATP capture and drug release.

A hyaluronidase-responsive polysaccharide supramolecular assembly was constructed from an amphiphilic β-cyclodextrin bearing seven hexylimidazolium units (AMCD), adamantyl-grafted hyaluronic acid, and chlorambucil, which showed specific cancer cell targeting and controlled drug release abilities. Interestingly, ternary supramolecular assembly can disassemble in the presence of hyaluronidase, and the released AMCD can assemble with ATP to form a stable 1 : 1 complex, which enhanced the efficacy of chlorambucil on cancer chemotherapy by inhibiting ATP hydrolysis.

Amphiphilic Cationic β-Cyclodextrin Derivatives Containing 2-(4-Isobutylphenyl)- and 2-(3-Benzoilphenyl) Propionic Acid Residues

The synthesis of amphiphilic cationic β-cyclodextrin derivatives that contain the residues of some pharmacologically important acids have been proposed. The acid residues have been attached to cyclodextrins through the linker of different lengths at the primary hydroxyl groups. The hydrophobic fragments of palmitic acid have been attached to both the primary and secondary hydroxyl groups.

Amphiphilic cationic cyclodextrin nanovesicles: a versatile cue for guiding cell adhesion.

It is well known that amphiphilic cationic β-cyclodextrins (amβCDs) form nanovesicles able to release their cargo in aqueous solution upon applying different stimuli. In addition they can be selectively positioned onto substrates by unconventional soft lithography. This makes them a powerful tool for designing environments where different cues can be externally supplied to the cells helping to achieve good control of their fate. Lithographically controlled wetting (LCW) of amβCD nanovesicles loaded with fluorescein isothiocyanate (FITC), amβCD/FITC, has been used here to fabricate geometrically functionalized surfaces, thus achieving multiscale control of the cell environment. The amβCD functionalization was strongly influenced by the surface energy of the underlying substrates that, according to their hydrophobicity, orient the amβCD in a different way, thus “offering” different portions to the cells. The structure of the pattern was characterized both over large scales exploiting the FITC fluorescence and at the nanoscale by atomic force microscopy. Cell guidance and aCD/FITC cell internalization were demonstrated in human neuroblastoma SHSY5Y cells.

Micelles via self-assembly of amphiphilic beta-cyclodextrin block copolymers as drug carrier for cancer therapy

We developed intelligent, star-shaped amphiphilic β-cyclodextrin (β-CD) co-polymer nanocarriers to circumvent the poor drug loading and water-solubility of β-CD. The secondary hydroxyl groups of β-CD were methylated to improve solubility, and the primary hydroxyl groups were conjugated with mPEG-b-PCL-SH through disulfide linkage to amplify the hydrophobic cavity and enhance the stability of the nanocarrier. A series of amphiphilic β-CD block copolymers (CCPPs) differing in molecular weights were synthesized that could self-assemble into core-shell nanospheres measuring 50–70 nm in water. The different CCPP carriers were screened for their drug loading, encapsulation and release efficiencies, and CCPP-2 showed the highest drug loading capacity of 31.9% by weight. These nanocarriers accumulated at the tumor site through the EPR effect and released the drug in a controlled manner in the reductive tumor microenvironment, with negligible premature leakage and side effects. Therefore, CCPP-2 shows significant potential as a smart and efficient nanovehicle for anticancer drug delivery.

Amphipathic β-cyclodextrin nanocarriers serve as intelligent delivery platform for anticancer drug

A novel glutathione-responsive (GSH-responsive) star-like amphiphilic polymer (C12H25)14-β-CD-(S-S-mPEG)7 (denoted as CCSP) was designed for efficient antitumor drug delivery. The amphiphilic β-cyclodextrin (β-CD) self-polymerize in water to form a sphere with a diameter of 40–50 nm. The secondary hydroxyl groups of β-CD were modified by dodecyl to form a hydrophobic core and the primary hydroxyl groups of β-CD were decorated with PEG through disulfide bond to form a hydrophilic shell. Since the hydrophobic cavity of β-CD was maintained, the hydrophobic core formed by dodecyl as well as cavity of β-CD provided CCSP with a loading content as high as 39.6 wt%. Importantly, DOX@CCSP exhibited low drug leakage and negligible cytotoxicity in non-reductive physiological environment, while it showed rapid release and high cytotoxicity in reductive tumorous environment via the breakage of disulfide bond. In view of the above-mentioned advantages of DOX@CCSP nanocarriers such as high loading content, proper size, favorable stimulus-response release performance and low leakage, it is believed that CCSP may offer great potential to be used as an intelligent nanocarrier for anticancer drug delivery.

Design and application of cationic amphiphilic β-cyclodextrin derivatives as gene delivery vectors

The nano self-assembly profiles of amphiphilic gene delivery vectors could improve the density of local cationic head groups to promote their DNA condensation capability and enhance the interaction between cell membrane and hydrophobic tails, thus increasing cellular uptake and gene transfection. In this paper, two series of cationic amphiphilic β-cyclodextrin (β-CD) derivatives were designed and synthesized by using 6-mono-OTs-β-CD (1) as the precursor to construct amphiphilic gene vectors with different building blocks in a selective and controlled manner. The effect of different type and degree of cationic head groups on transfection and the endocytic mechanism of β-CD derivatives/DNA nanocomplexes were also investigated. The results demonstrated that the designed β-cyclodextrin derivatives were able to compact DNA to form stable nanocomplexes and exhibited low cytotoxicity. Among them, PEI-1 with PEI head group showed enhanced transfection activity, significantly higher than commercially available agent PEI25000 especially in the presence of serum, showing potential application prospects in clinical trials. Moreover, the endocytic uptake mechanism involved in the gene transfection of PEI-1 was mainly through caveolae-mediated endocytosis, which could avoid the lysosomal degradation of loaded gene, and had great importance for improving gene transfection activity.

Cavity Orientation Regulated by Mixture Composition and Clustering of Amphiphilic Cyclodextrins in Phospholipid Monolayers.

Artificial supramolecular-hierarchical structures that emulate nature represent an overcoming alternative for the design of new drug delivery systems. Thermodynamic and topographic properties of films formed by a monoacylated amphiphilic β-cyclodextrin (βCD-C16) with the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at the air/water interface were studied. βCD-C16 formed stable mixed films with POPC at several proportions when spread together at the air/water interface. The orientation of βCD-C16 cavity at the interface depends on its mole fraction in the film as reveled by the analysis of partial mean molecular areas as a function of composition. Furthermore, βCD-C16 was able to penetrate POPC preformed films in a broad range of initial surface pressures, including that near the collapse pressure of the phospholipid. These results demonstrated the strong tendency of βCD-C16 to be inserted into this lipid matrix commonly used in liposome formulations. Topography studies show that βCD-C16 segregate from POPC forming clusters enriched in βCD-C16. Segregation of βCD-C16 was especially noticeable when βCD-C16 were incorporated by themselves into a preformed POPC matrix leading to ordered and highly birefringent structures that suggest the formation of hierarchical stacked βCD-C16 arrangement at the interface.

A Self-Assembled Sensor for Carbohydrates on the Surface of Cyclodextrin Vesicles.

A supramolecular carbohydrate sensor was prepared by self-assembly of unilamellar bilayer vesicles of amphiphilic β-cyclodextrin with a boronic acid-adamantane conjugate (PBA-AD), which binds strongly to β-cyclodextrin through host-guest interactions (Ka ≈4×104 m-1 ), so the vesicle surface exhibits multiple boronic acid receptors for carbohydrates. The binding of diols to the functionalized vesicles was tested with alizarin red S (ARS) as a reporter dye by using fluorescence and UV/Vis spectroscopy. Analysis of the competitive binding of monosaccharides revealed pH-dependent (pH 7.4-10.1) binding constants in the range of 100-3000 m-1 for d-fructose and 5-400 m-1 for d-glucose. Interestingly, the self-assembled sensor showed fluorescence intensity enhanced by about fivefold and a binding affinity to the reporter dye increased by about eightfold in comparison to PBA-AD and ARS without vesicles. This is attributed to increased local concentration of ARS and PBA-AD on the surface of the vesicles. Detection of d-fructose and d-glucose was possible in the physiologically relevant range in dilute aqueous solution.

Synthesis and thermo-responsive self-assembly behavior of amphiphilic copolymer β-CD–(PCL–P(MEO2MA-co-PEGMA))21 for the controlled intracellular delivery of doxorubicin

Well-defined amphiphilic β-cyclodextrin star-shaped copolymers with poly(ε-caprolactone)–poly(2-(2-methoxyethoxy)ethyl methacrylate)-co-poly(ethylene glycol)methacrylate) (β-CD–(PCL–P(MEO2MA-co-PEGMA))21 were synthesized via (ROP) and (ATRP).

NMR study of inclusion complexes formation between amphiphilic dimeric β-cyclodextrin derivative and some pharmacologically important compounds

With the use of monotosyl β-cyclodextrin derivative and 1,6-hexanediamine the new dimeric (bridged) amphiphilic derivative was obtained, and the opportunity to form on its base inclusion complexes of “guest–host” type with some pharmacologically important compounds was demonstrated by 1H and 13C NMR spectroscopy.

Probing into the Supramolecular Driving Force of an Amphiphilic β-Cyclodextrin Dimer in Various Solvents: Host-Guest Recognition or Hydrophilic-Hydrophobic Interaction?

Tuning of the morphology and size of supramolecular self-assemblies is of theoretical and practical significance. To date, supramolecular driving forces in different solvents remain unclear. In this study, we first synthesized an amphiphilic β-cyclodextrin (β-CD) dimer that consists of one hydrophobic ibuprofen (Ibu) and two hydrophilic β-CD moieties (i.e., Ibu-CD2). Ibu-CD2 possesses double supramolecular driving forces, namely, the host-guest recognition and hydrophilic-hydrophobic interaction. The host-guest interaction of Ibu-CD2 induced the formation of branched supramolecular polymers (SPs) in pure water, whereas the hydrophilic-hydrophobic interaction generated spherical or irregular micelles in water/organic mixtures. The SP size increased with the increase in Ibu-CD2 concentration in pure water. By contrast, the size of micelles decreased with the increase in volume ratio of water in mixtures.

Back Cover: Ultrasound-Driven Secondary Self-Assembly of Amphiphilic β-Cyclodextrin Dimers (Chem. Eur. J. 13/2015)

Controlled secondary self-assembly of amphiphilic molecules in solution has theoretical and practical significance in amphiphilic molecular applications. In their Full Paper on page 5000 ff., X.-D. Fan, W. Tian, and co-workers describe the design of an amphiphilic β-cyclodextrin dimer, which can self-assemble into spherical micelles in aqueous solution without ultrasonication. While the primary micelles were dissociated under the action of ultrasonication; the secondary self-assemblies possessing branched morphology could be formed by further increasing the ultrasonication time.