ABSTRACT
Rotaxane cross-linkers enhance the toughness of the resulting rotaxane cross-linked polymers through a stress dispersion effect, which is attributed to the mobility of the interlocked structure. To date, the compositional diversity of rotaxane cross-linkers has been limited, and the poor compatibility of these cross-linkers with peptides and proteins has made their use in such materials challenging. The synthesis of a rotaxane composed of peptides may result in a biodegradable cross-linker that is compatible with peptides and proteins, allowing the fortification of polypeptides and proteins and ultimately leading to the development of innovative materials that possess excellent mechanical properties and biodegradability. However, the chemical synthesis of all-peptide-based rotaxanes has remained elusive because of the absence of strong binding motifs in peptides, which prevents an axial peptide from penetrating a cyclic peptide. Here, we synthesized all-peptide-based rotaxanes using an active template method for proline-containing cyclic peptides. The results of molecular dynamics simulations suggested that cyclic peptides with an expansive inner cavity and carbonyl oxygens oriented toward the center are favorable for rotaxane synthesis. This rotaxane synthesis method is expected to accelerate the synthesis of peptides and proteins with mechanically interlocked structures, potentially leading to the development of peptide- and protein-based materials with unprecedented functionalities.
Subject(s)
Peptides, Cyclic , Proline , Rotaxanes , Rotaxanes/chemistry , Rotaxanes/chemical synthesis , Proline/chemistry , Peptides, Cyclic/chemistry , Peptides, Cyclic/chemical synthesis , Molecular Dynamics SimulationABSTRACT
Cyclodextrins (CDs) are essential in the pharmaceutical industry and have long been used as food and pharmaceutical additives. CD-based interlocked molecules, such as rotaxanes, polyrotaxanes, catenanes, and polycatenanes, have been synthesized and have attracted considerable attention in supramolecular chemistry. Among them, CD polyrotaxanes have been employed as slide-ring materials and biomaterials. CD polycatenanes are new materials; therefore, to date, no examples of applied research on CD polycatenanes have been reported. Consequently, we expect that applied research on CD polycatenanes will accelerate in the future. This review article summarizes the syntheses and structural analyses of CD polyrotaxanes and polycatenanes to facilitate their applications in the pharmaceutical industry. We believe that this review will promote further research on CD-based interlocked molecules.
Subject(s)
Cyclodextrins , Poloxamer , Rotaxanes , Rotaxanes/chemistry , Rotaxanes/chemical synthesis , Cyclodextrins/chemistry , Cyclodextrins/chemical synthesis , Catenanes/chemistry , Catenanes/chemical synthesis , Biocompatible Materials/chemistry , Biocompatible Materials/chemical synthesisABSTRACT
Polypseudorotaxanes constructed from pillar[5]arene rings and polyamide chains were successfully synthesized by interfacial polymerization between diamines and dicarbonyl chlorides in the presence of pillar[5]arene. The dicarbonyl chloride length and the assocation constants of dicarbonyl chloride-pillar[5]arene complexes were important factors in producing polypseudorotaxanes with high cover ratio of pillar[5]arene rings.
Subject(s)
Calixarenes/chemistry , Cyclodextrins/chemistry , Nylons/chemistry , Poloxamer/chemistry , Quaternary Ammonium Compounds/chemistry , Rotaxanes/chemistry , Chlorides/chemistry , Cyclodextrins/chemical synthesis , Magnetic Resonance Spectroscopy , Poloxamer/chemical synthesis , Polymerization , Rotaxanes/chemical synthesisABSTRACT
Polypseudorotaxane structure and polydopamine bond-based crosslinked hyaluronic acid (HA) hydrogels including donepezil-loaded microspheres were developed for subcutaneous injection. Both dopamine and polyethylene glycol (PEG) were covalently bonded to the HA polymer for catechol polymerization and inclusion complexation with alpha-cyclodextrin (α-CD), respectively. A PEG chain of HA-dopamine-PEG (HD-PEG) conjugate was threaded with α-CD to make a polypseudorotaxane structure and its pH was adjusted to 8.5 for dopamine polymerization. Poly(lactic-co-glycolic acid) (PLGA)/donepezil microsphere (PDM) was embedded into the HD-PEG network for its sustained release. The HD-PEG/α-CD/PDM 8.5 hydrogel system exhibited an immediate gelation pattern, injectability through single syringe, self-healing ability, and shear-thinning behavior. Donepezil was released from the HD-PEG/α-CD/PDM 8.5 hydrogel in a sustained pattern. Following subcutaneous injection, the weight of excised HD-PEG/α-CD/PDM 8.5 hydrogel was higher than the other groups on day 14. These findings support the clinical feasibility of the HD-PEG/α-CD/PDM 8.5 hydrogel for subcutaneous injection.
Subject(s)
Drug Carriers/chemistry , Hyaluronic Acid/analogs & derivatives , Hydrogels/chemistry , Indoles/chemistry , Polymers/chemistry , Animals , Biodegradable Plastics/chemical synthesis , Biodegradable Plastics/chemistry , Biodegradable Plastics/toxicity , Cyclodextrins/chemical synthesis , Cyclodextrins/chemistry , Cyclodextrins/toxicity , Donepezil/chemistry , Drug Carriers/chemical synthesis , Drug Carriers/toxicity , Drug Liberation , Hyaluronic Acid/toxicity , Hydrogels/chemical synthesis , Hydrogels/toxicity , Indoles/chemical synthesis , Indoles/toxicity , Male , Mice, Inbred ICR , Microspheres , Poloxamer/chemical synthesis , Poloxamer/chemistry , Poloxamer/toxicity , Polymers/chemical synthesis , Polymers/toxicity , Rotaxanes/chemical synthesis , Rotaxanes/chemistry , Rotaxanes/toxicity , Viscoelastic Substances/chemical synthesis , Viscoelastic Substances/chemistry , Viscoelastic Substances/toxicityABSTRACT
The precise operation of molecular motion for constructing complicated mechanically interlocked molecules has received considerable attention and is still an energetic field of supramolecular chemistry. Herein, we reported the construction of two tris[2]pseudorotaxanes metallacycles with acid-base controllable molecular motion through self-sorting strategy and host-guest interaction. Firstly, two hexagonal Pt(II) metallacycles M1 and M2 decorated with different host-guest recognition sites have been constructed via coordination-driven self-assembly strategy. The binding of metallacycles M1 and M2 with dibenzo-24-crown-8 (DB24C8) to form tris[2]pseudorotaxanes complexes TPRM1 and TPRM2 have been investigated. Furthermore, by taking advantage of the strong binding affinity between the protonated metallacycle M2 and DB24C8, the addition of trifluoroacetic acid (TFA) as a stimulus successfully induces an acid-activated motion switching of DB24C8 between the discrete metallacycles M1 and M2. This research not only affords a highly efficient way to construct stimuli-responsive smart supramolecular systems but also offers prospects for precisely control multicomponent cooperative motion.
Subject(s)
Organoplatinum Compounds/chemistry , Platinum/chemistry , Rotaxanes/chemistry , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Crown Ethers/chemistry , Molecular Structure , Organoplatinum Compounds/chemical synthesis , Polymers/chemical synthesis , Polymers/chemistry , Rotaxanes/chemical synthesis , Trifluoroacetic Acid/chemistryABSTRACT
The efficacy of many drugs can be limited by undesirable properties, such as poor aqueous solubility, low bioavailability, and "off-target" interactions. To combat this, various drug carriers have been investigated to enhance the pharmacological profile of therapeutic agents. In this work, we demonstrate the use of mechanical protection to "cage" a DNA-targeting metallodrug within a photodegradable rotaxane. More specifically, we report the synthesis of rotaxanes incorporating as a stoppering unit a known G-quadruplex DNA binder, namely a PtII -salphen complex. This compound cannot interact with DNA when it is part of the mechanically interlocked assembly. The second rotaxane stopper can be cleaved by either light or an esterase, releasing the PtII -salphen complex. This system shows enhanced cell permeability and limited cytotoxicity within osteosarcoma cells compared to the free drug. Light activation leads to a dramatic increase in cytotoxicity, arising from the translocation of PtII -salphen to the nucleus and its binding to DNA.
Subject(s)
DNA/drug effects , Rotaxanes/chemistry , Small Molecule Libraries/pharmacology , Binding Sites/drug effects , Cell Survival/drug effects , DNA/chemistry , Humans , Molecular Structure , Rotaxanes/chemical synthesis , Small Molecule Libraries/chemistryABSTRACT
The development of integrated systems that mimic the multi-stage stiffness change of marine animals such as the sea cucumber requires the design of molecularly tailored structures. Herein, we used an integrated biomimicry design to fabricate a sea cucumber mimic using sidechain polypseudorotaxanes with tunable nano-to-macroscale properties. A series of polyethylene glycol (PEG)-based sidechain copolymers were synthesized to form sidechain polypseudorotaxanes with α-cyclodextrins (α-CDs). By tailoring the copolymers' molecular weights and their PEG grafting densities, we rationally tuned the sizes of the formed polypseudorotaxanes crystalline domain and the physical crosslinking density of the hydrogels, which facilitated 3D printing and the mechanical adaptability to these hydrogels. After 3D printing and photo-crosslinking, the obtained hydrogels exhibited large tensile strain and broad elastic-to-plastic variations upon α-CD (de)threading. These discoveries enabled a successful fabrication of a sea cucumber mimic, demonstrating multi-stage stiffness changes.
Subject(s)
Polymers/chemical synthesis , Rotaxanes/chemical synthesis , Animals , Molecular Structure , Polyethylene Glycols/chemistry , Polymers/chemistry , Rotaxanes/chemistry , Sea CucumbersABSTRACT
A twin-axial pseudorotaxane is constructed using a phenylpyridine salt with diethanolamine (DA-PY) and cucurbit[8]uril (CB[8]), and it not only displays phosphorescence in aqueous solution but it can also be used for targeted cell-imaging.
Subject(s)
Luminescent Agents/chemical synthesis , Rotaxanes/chemical synthesis , Single-Cell Analysis/methods , A549 Cells , Humans , Luminescent Agents/chemistry , Luminescent Agents/metabolism , Rotaxanes/chemistry , Rotaxanes/metabolismABSTRACT
In this study, novel copillar[4+1]arenes were used as central heteromultivalent scaffolds via orthogonal couplings with a series of biologically relevant molecules such as carbohydrates, α-amino acids, biotin and phenylboronic acid. Further modifications by introducing maleimides or cyclooctyne groups provided molecular probes adapted to copper-free click chemistry. An octa-azidated fluorescent rotaxane bearing two distinct ligands was also generated in a fully controlled manner.
Subject(s)
Macrocyclic Compounds/chemistry , Molecular Probes/chemistry , Rotaxanes/chemistry , Macrocyclic Compounds/chemical synthesis , Molecular Probes/chemical synthesis , Molecular Structure , Rotaxanes/chemical synthesisABSTRACT
The entrapment of squaraine (SQ) within a molecular container to form rotaxane has been shown to improve the dye stability and the fluorescence proficiency inside the mitochondria. The macrocycle provides shelter and protects the near-infrared (NIR) SQ chromophore from nucleophilic attacks made by the exposed thiol of Cys-containing mitochondrial proteins and mitochondrial glutathione. Herein a microwave-assisted template-directed clipping reaction on low-loading 2-chlorotrityl chloride resin is used to develop an NIR unsymmetrical squaraine rotaxane in high quantum yield.
Subject(s)
Cyclobutanes/chemical synthesis , Fluorescent Dyes/chemistry , Mitochondria , Phenols/chemical synthesis , Rotaxanes/chemistry , Infrared Rays , Magnetic Resonance Spectroscopy , Molecular Structure , Rotaxanes/chemical synthesisABSTRACT
We present a simple strategy for the synthesis of main chain oligonucleotide rotaxanes with precise control over the position of the macrocycle. The novel DNA-based rotaxanes were analyzed to assess the effect of the mechanical bond on their properties.
Subject(s)
Copper/chemistry , DNA/chemical synthesis , Oligonucleotides/chemical synthesis , Rotaxanes/chemical synthesis , Alkynes/chemical synthesis , Alkynes/chemistry , Azides/chemical synthesis , Azides/chemistry , Click Chemistry , Cycloaddition Reaction , DNA/chemistry , Macrocyclic Compounds/chemical synthesis , Macrocyclic Compounds/chemistry , Oligonucleotides/chemistry , Rotaxanes/chemistryABSTRACT
Drug delivery carriers hold tremendous promise for improving cancer treatment, and polyrotaxane (PR) has shown excellent drug-carrying properties. However, there have been some reports that, when used as a drug carrier, water-soluble PR is not easily labeled with organic fluorescent dyes. Herein, we synthesized a drug-loaded fluorescent porphyrin-terminated PR (PR-COOH) which can be used as a tracer material in drug and gene delivery. The structure, morphology and zeta potential of PR-COOH were characterized by nuclear magnetic resonance, high-resolution transmission electron microscopy and zeta potentiometry. In this research, cisplatin (CDDP) is used as a model drug. The zeta potential, drug encapsulation efficiency and drug release of CDDP-loaded PR (PR-COOH-Pt) were studied. Confocal laser scanning microscopy showed that PR-COOH could be internalized by HeLa and CT26 cells. The antitumor efficacy of PR-COOH-Pt was investigated in vitro by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and in vivo by a xenograft tumor model. The results showed that PR-COOH-Pt could significantly inhibit tumor growth; thus PR-COOH-Pt has a promising role in cancer therapy.
Subject(s)
Antineoplastic Agents/administration & dosage , Cisplatin/administration & dosage , Cyclodextrins/chemical synthesis , Liver Neoplasms/drug therapy , Poloxamer/chemical synthesis , Porphyrins/chemistry , Rotaxanes/chemical synthesis , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Cisplatin/chemistry , Cisplatin/pharmacology , Cyclodextrins/chemistry , Drug Carriers/chemistry , Drug Liberation , HeLa Cells , Humans , Magnetic Resonance Spectroscopy , Mice , Nanoparticles , Poloxamer/chemistry , Rotaxanes/chemistry , Xenograft Model Antitumor AssaysABSTRACT
Diphenanthrioctaphyrin(1.1.1.0.1.1.1.0), an expanded carbaporphyrinoid incorporating two phenanthrenylene moieties, exists as two separate, yet interconvertible, locked stereoisomers. These species demonstrate complex dynamic behavior upon protonation, consisting in multiple conformational rearrangements and anion-binding events. The formation of one of the final dicationic forms is accompanied by the inclusion of a complex anion(s) within the macrocyclic cavity yielding a pseudorotaxane-like host-guest complex. Protonation with trifluoroacetic or dichloroacetic acids followed by neutralization afforded a conformation-switching cycle, which involves six structurally different species. Analogous acidification with chiral 10-camphorsulfonic acid and subsequent neutralization generated one of the free base stereoisomers with enantiomeric excess. Therefore, it was shown that the simple acid-base chemistry of diphenanthrioctaphyrin can act as stimulus, inducing chirality into the system, allowing for the manipulation of the stereochemical information imprinted into the enantiomers of the macrocycle.
Subject(s)
Anions/chemistry , Rotaxanes/chemistry , Hydrogenation , Molecular Conformation , Rotaxanes/chemical synthesis , StereoisomerismABSTRACT
Polyrotaxanes, consisting of poly(ethylene glycol) and α-cyclodextrins, are mechanically interlocked supermolecules. The structure allows α-cyclodextrins to move along the polymer, referred to as molecular mobility. Here, polyrotaxane-based triblock copolymers, composed of polyrotaxanes with different degrees of methylation and poly(benzyl methacrylate) at both terminals, are coated on culture surfaces to fabricate dynamic biointerfaces for myocyte differentiation. The molecular mobility increases with the degree of methylation and the contact angle hysteresis of water droplets and air bubbles. When the mouse myoblast cell line C2C12 is cultured on methylated polyrotaxane surfaces, the expression levels of myogenesis-related genes, myogenin (Myog) and myosin heavy chain (Myhc) are altered by the degree of methylation. Polyrotaxane surfaces with intermediate degrees of methylation promote the highest expression levels among all the surfaces. The polyrotaxane surface provides an appropriate environment for myocyte differentiation by accurately adjusting the degrees of methylation.
Subject(s)
Biocompatible Materials/chemical synthesis , Cyclodextrins/chemical synthesis , Muscle Cells/drug effects , Muscle Development/drug effects , Myoblasts/drug effects , Poloxamer/chemical synthesis , Polymethacrylic Acids/chemistry , Rotaxanes/chemical synthesis , Air/analysis , Animals , Biocompatible Materials/pharmacology , Biomarkers/metabolism , Cell Differentiation/drug effects , Cell Line , Cyclodextrins/pharmacology , Gene Expression , Methylation , Mice , Muscle Cells/cytology , Muscle Cells/metabolism , Muscle Development/genetics , Myoblasts/cytology , Myoblasts/metabolism , Myogenin/genetics , Myogenin/metabolism , Myosin Heavy Chains/genetics , Myosin Heavy Chains/metabolism , Poloxamer/pharmacology , Rotaxanes/pharmacology , Structure-Activity Relationship , Water/chemistryABSTRACT
The interlocking of ring and axle molecular components in rotaxanes provides a way to combine chromophoric, electron-donor and electron-acceptor moieties in the same molecular entity, in order to reproduce the features of photosynthetic reaction centers. To this aim, the photoinduced electron transfer processes involving a 1,8-naphthalimide chromophore, embedded in several rotaxane-based dyads, were investigated by steady-state and time-resolved absorption and luminescence spectroscopic experiments in the 300â fs-10â ns time window. Different rotaxanes built around the dialkylammonium/ dibenzo[24]crown-8 ether supramolecular motif were designed and synthesized to decipher the relevance of key structural factors, such as the chemical deactivation of the ammonium-crown ether recognition, the presence of a secondary site for the ring along the axle, and the covalent functionalization of the macrocycle with a phenothiazine electron donor. Indeed, the conformational freedom of these compounds gives rise to a rich dynamic behavior induced by light and may provide opportunities for investigating and understanding phenomena that take place in complex (bio)molecular architectures.
Subject(s)
Naphthalimides/chemistry , Rotaxanes/chemistry , Crown Ethers/chemistry , Electron Transport , Light , Phenothiazines/chemistry , Quantum Theory , Rotaxanes/chemical synthesis , Spectrometry, FluorescenceABSTRACT
In this study, an electroactive rotaxane, (S,S)-crown-3, consisting of a polymeric chiral ionic liquid as a flexible axle and 18-crown-6 as the wheel, was designed and synthesized. It is worth noting that a stimuli-responsive system was developed, in which the wheel could switch its location between the chiral carbamido group and ionic pair of the ionic polymers under an external force. Next, (S,S)-crown-3 was employed as a modification on the surface of glassy electrode. In contrast to previous study, the developed probe presented a clear discrimination of an electrochemical signal in the absence of Cu(ii). Under the external force (different pH values), l-isomers of amino acids (tryptophan, tyrosine, and cysteine) could form stable host-guest interactions with the chiral carbamido group, producing higher peak currents than the d-isomers. Compared to the absence of the crown, (S,S)-crown-3 showed much better recognition efficiency. The value of IL/ID for tryptophan could reach 39.8. In brief, the present study describes a powerful method for the synthesis of an electroactive rotaxane with great enantiorecognition capability.
Subject(s)
Amino Acids/chemistry , Rotaxanes/chemistry , Rotaxanes/chemical synthesis , Chemistry Techniques, Synthetic , Electrochemistry , Spectrum Analysis , StereoisomerismABSTRACT
A rotaxane-based molecular shuttle has been synthesized in which the switching of the position of a fluorescent macrocycle on the thread turns "on" or "off" the circularly polarized luminescence (CPL) of the system while maintaining similar fluorescence profiles and quantum yields in both states. The chiroptical activity relies on the chiral information transfer from an ammonium salt incorporating d- or l-phenylalanine residues as chiral stereogenic covalent units to an otherwise achiral crown ether macrocycle bearing a luminescent 2,2'-bipyrene unit when they interact through hydrogen bonding. Each enantiomeric thread induces CPL responses of opposite signs on the macrocycle. Upon addition of base, the switching of the position of the macrocycle to a triazolium group disables the chiral information transfer to the macrocycle, switching "off" the CPL response. The in situ switching upon several acid/base cycles is also demonstrated.
Subject(s)
Rotaxanes/chemistry , Luminescence , Luminescent Measurements , Proof of Concept Study , Rotaxanes/chemical synthesis , StereoisomerismABSTRACT
Reversible covalent bonds yield polymeric materials with functional characteristics such as self-healing, shape memory, stress relaxation, and stimuli-responsiveness. Here, photo-reversibly cappable polyrotaxanes are designed and the on-off controlled dissociation of their supramolecular architectures is demonstrated. The polyrotaxanes are synthesized by capping dithiobenzoates at both terminals of polyethylene glycol threaded through multiple α-cyclodextrins. Since dethreading of the α-cyclodextrins is prevented by the dithiobenzoate stoppers, the supramolecular dissociation is induced by their photo-cleavage. Subsequently, the cleaved dithiobenzoates spontaneously re-cap the polyrotaxane terminals in darkness. Thus, the supramolecular dissociation can be modulated by photo-reversible capping of the dithiobenzoate stoppers. These polyrotaxanes with dithiobenzoate stoppers are promising functional materials for photo-controlling physical properties and structures.
Subject(s)
Cyclodextrins/chemistry , Light , Poloxamer/chemistry , Rotaxanes/chemistry , Benzoates/chemistry , Cyclodextrins/chemical synthesis , Poloxamer/chemical synthesis , Polyethylene Glycols/chemistry , Rotaxanes/chemical synthesis , alpha-Cyclodextrins/chemistryABSTRACT
Room temperature phosphorescent (RTP) γ-CD-CB[6]-cowheeled [4]rotaxanes were synthesized by implanting a naphthalene axle into the cavity of iodine-substituted γ-CDs. The strong green RTP was quenched exclusively by Trp while no RTP quenching was observed with other major physiological amino acids or with the Trp-containing protein HSA, demonstrating a highly specific sensing of free Trp.
Subject(s)
Bridged-Ring Compounds/chemistry , Imidazoles/chemistry , Luminescent Agents/chemistry , Rotaxanes/chemistry , Tryptophan/analysis , gamma-Cyclodextrins/chemistry , Bridged-Ring Compounds/chemical synthesis , Humans , Imidazoles/chemical synthesis , Luminescent Agents/chemical synthesis , Luminescent Measurements/methods , Rotaxanes/chemical synthesis , Temperature , Tryptophan/blood , gamma-Cyclodextrins/chemical synthesisABSTRACT
Macrophages play an important role in the regulation of inflammation and immune response as well as the pathogenesis of chronic inflammatory diseases and cancer. Therefore, targeted delivery of therapeutic reagents to macrophages is an effective method for treatment and diagnosis. We previously examined the therapeutic applications of polyrotaxanes (PRXs) comprised of multiple cyclodextrins (CDs) threaded on a polymer chain and capped with bulky stopper molecules. In the present study, we designed an α-d-mannose-modified α-CD/poly(ethylene glycol)-based PRX (Man-PRX). The intracellular uptake of Man-PRX through the interaction with macrophage mannose receptor (MMR) in macrophage-like RAW264.7 cells was examined. Intracellular Man-PRX uptake was observed in MMR-positive RAW264.7 cells but was negligible in MMR-negative NIH/3T3 cells. In addition, the intracellular Man-PRX uptake in RAW264.7 cells was significantly inhibited in the presence of free α-d-mannose and an anti-MMR antibody, which suggests that MMR is involved in the intracellular uptake of Man-PRX. Moreover, the polarization of RAW264.7 cells affected the Man-PRX internalization efficiency. These results indicate that Man-PRX is an effective candidate for selective targeting of macrophages through a specific interaction with the MMR.