Search Results (62)

Large bone defects resulting from trauma, tumor resection, infection, or degenerative diseases pose a major clinical challenge in orthopedic surgery and regenerative medicine. Despite advances in biomaterials and surgical techniques, successful outcomes are often compromised by poor vascularization, limited osteoinduction, and donor-site morbidity associated with autografts or allografts. However, conventional delivery systems suffer from burst release, rapid clearance, off-target effects, and supraphysiologic dosing, which can lead to undesirable complications such as ectopic ossification and inflammation, with some reports raising concerns about the long-term tumorigenic risk. Heparin, a naturally highly sulfated glycosaminoglycan structurally related to heparan sulfate, has emerged as a particularly attractive candidate for affinity-based biomaterial systems. It naturally binds over 300 growth factors, including bone morphogenetic proteins. By protecting these proteins from enzymatic degradation, enhancing their bioavailability, and mediating receptor clustering, heparin provides both biochemical stability and biofunctional modulation. This review provides a comprehensive overview of heparin-based delivery strategies in bone tissue engineering. We begin by describing the biological functions of heparin in modulating growth factor activity. We then discuss in detail the different heparin-based biomaterials designed to sustain the release of growth factors for bone tissue engineering, including the heparin–polycation coacervate system; heparin-based supramolecules; and heparin-based hydrogels, nanoparticles, and microspheres for sustained release of bone morphogenic proteins and other growth factors for bone tissue engineering. Finally, we assess the clinical and translational relevance of heparin-based systems, identify key challenges, and outline future perspectives, highlighting the potential of these biomaterials for providing safer and more effective therapies for bone regeneration. Full article

Main-chain conjugated and non-conjugated polyelectrolytes are an important class of materials that have many technological applications ranging from fire-retardant materials to carbon-nanotube composites, nonlinear optical materials, electrochromic materials for smart windows, and optical sensors for biomolecules. Here, we describe a series of poly(pyridinium salt)s-fluorene containing 9,9-bis(4-aminophenyl)fluorene moieties with various organic counterions that were synthesized using ring-transmutation polymerization and metathesis reactions, which are non-conjugated polyelectrolytes. Their chemical structures were characterized by Fourier transform infrared (FTIR), proton (¹H) and fluorine 19 (¹⁹F) nuclear magnetic resonance (NMR) spectrometers, and elemental analysis. They exhibited polyelectrolytic behavior in dimethyl sulfoxide. Their lyotropic liquid-crystalline phases were examined by polarizing optical microscopy (POM) and small angle X-ray scattering (SAXS) studies. Their emission spectra exhibited a positive solvatochromism on changing the polarity of solvents. They emitted greenish-yellow lights in polar organic solvents. They formed aggregates in polar aprotic and protic solvents with the addition of water (v/v, 0–90%), whose λ_em peaks were blue shifted. Full article

We report on the preparation and characterization of a new family of hydrogen-bonded nematogenic liquid crystalline dimers. The dimers are supramolecular complexes that consist of a benzoic acid derivative, acting as the proton donor, featuring a spacer with seven methylene groups and a terminal decyloxy chain, paired with an azopyridine derivative as the proton acceptor. The latter was either fluorinated or nonfluorinated with variable alkoxy chain length. The formation of a hydrogen bond between the individual components was confirmed using FTIR and ¹H NMR spectroscopy. All supramolecules were investigated for their liquid crystalline behaviour via a polarized optical microscope (POM) and differential scanning calorimetry (DSC). All materials exhibit enantiotropic nematic phases as confirmed by X-ray diffraction (XRD) and POM investigations. The nematic phase range depends strongly on the degree and position of fluorine atoms. Additionally, the supramolecules demonstrated a rapid and reversible transition between the liquid crystal phase and the isotropic liquid state because of trans-cis photoisomerization upon light irradiation. Therefore, this study presents a straightforward approach to design photo-responsive nematic materials, which could be of interest for nonlinear optics applications. Full article

We demonstrate a rapid and sensitive boron detection method through current amplification mediated by supramolecular interaction. Oxidation peak currents obtained by cyclic voltammetry (CV) measurements of a ferrocene/catechol-functionalized β-cyclodextrin inclusion complex were amplified through an EC’ reaction (where EC’ denotes an electrochemical step followed by a catalytic chemical step). However, the amplified current was decreased by boric acid (the primary form of boron in water) addition at pH 8.6 owing to interactions of boron with the cis-diol structure of dihydroxybenzoic acid-β-cyclodextrin and ferrocene for ester formation. We determined the optimum CyD functionalization sites and measurement conditions and obtained a limit of detection of 0.16 mg B L⁻¹ for ferrocene/3,4-dihydroxybenzoic acid-β-cyclodextrin (Fc/3,4-DHBA-β-CyD). The binding constant (assuming a 1:1 binding model) for the interaction between Fc/3,4-DHBA-β-CyD and boric acid was estimated to be approximately 1500 M⁻¹. Boron concentrations in spiked real samples showed good recoveries and linear calibration curves. The electrochemical response of this system was not significantly affected by the presence of other anions or cations. We also found that an aqueous solution of 3,4-DHBA-β-CyD remained stable for at least 112 days. Full article

Structural rearrangements in metal–organic supramolecules constructed from the coordination of Cu(II) with m-xpt (m-xylylenebis(pyridyltriazole)) are investigated upon their interaction with 1,4-diazabicyclo[2.2.2]octane (dabco) and carbon dioxide-enriched air. The binuclear [Cu₂(m-xpt)₂]⁴⁺ complexes react with dabco to produce a carbonate-bridged trinuclear complex, [Cu₃(m-xpt)₃(µ-CO₃)]⁴⁺, and an oxalate-bridged binuclear complex, [Cu₂(m-xpt)₂(µ-C₂O₄)]²⁺, where carbonate and oxalate likely originate from CO₂ and dabco, respectively. The trinuclear complex reassembles the original dimer upon the removal of the carbonate ion. Similarly, polymeric [Cu(o-xpt)(PF₆)]_n, formed from Cu(I) and o-xpt (o-xylylenebis(pyridyltriazole)) coordination, undergoes oxidation in CO₂-enriched air to yield a tetranuclear Cu(II) complex, Cu₄(o-xpt)₃(μ₄-CO₃)(μ₂-OH)(μ₂-OCOCH₃)⁴⁺. The reaction progress is monitored by UV-Vis spectroscopy, and the major products are characterized by single-crystal X-ray diffraction. Full article

Amyloid fibril hydrogels prepared via protein acid heating currently exhibit inadequate gel properties and biological activity. These limitations can be addressed by modifying the amyloid fibrils with polyphenols. In this study, two types of polyphenols—tannic acid (TA) and gallic acid (GA)—were selected to prepare hydrogels with soy protein fibrils (SPIFs) at varying proportions to investigate structure, gel properties, and biological activity. TEM results revealed that polyphenols are deposited on the surface of SPIFs by hydrogen bonding and hydrophobic interaction to form hybrid supramolecules. The greater the mass ratio of polyphenols to SPIF, the more pronounced the structural changes. When the mass ratios of TA, GA, and SPIF were 1:20 and 1:2, respectively, the β-sheet content reached the maximum. The gel strength increased by 6 times and 5 times, respectively, with the modulus reaching 334.91 Pa and 317.79 Pa, respectively. The hydrogels exhibited optimal apparent viscosity and structural recovery properties. Bacteriostatic and cytotoxicity tests demonstrated that the hydrogels exhibited excellent antibacterial properties while maintaining safety. In summary, TA demonstrates significant advantages in remodeling SPIF at low concentrations, thereby enhancing the gel characteristics and antibacterial properties of the hydrogel. Full article

In this paper, we synthesized a chain-like organic cation structure directing agent L·Cl₂ by reacting triethylenediamine with 1,2-bis(2-chloroethoxy)ethane. We then used a room temperature volatilization method to react L·Cl₂ with inorganic metal salts to synthesize five organic–inorganic hybrid supramolecules: {[L][HgI₄]} (1), {[L][CdI₄]} (2), {[(L)(Cu₂I₃)]·[CuI₂]CH₃CN}_n (3) {[L][CoCl₃]₂} (4), and {[L][Ce(NO₃)₅·(H₂O)₂]} (5) (L=1,1′-((ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(1,4-diazabicyclo [2.2.2]octan-1-ium) chloride). The compounds were characterized by X-ray diffraction, infrared spectroscopy, elemental analysis, and thermogravimetric analysis. Compounds 1, 2, and 5 are mononuclear anion compounds, while compound 3 is a 1D chain, and 4 is a binuclear anion compound. The results showed that 10 mg of compound 3 achieved 92.22% of tetracycline degradation efficiency in the initial TC solution pH = 7. The optimal conditions such as solution pH, catalyst dosage, and solution temperature for the photocatalytic degradation of TC wastewater by compound 3 were explored. Moreover, the photocatalytic degradation efficiency of compound 3 was above 86% each time after four cycles, indicating a good recyclability. The mechanism of photocatalytic degradation was also discussed. Full article

Conventional cancer drugs are small molecules that target specific pathways. We introduced PCMS, a 26 kDa supramolecule combining sensors (S), molecular motors (M), and switching molecules (C), integrated within a fourth-generation PAMAM structure (P). PCMS identifies and deactivates cancer cell nucleus dynamics. A decade ago, we demonstrated programmable, clock-like interactions among the S-C-M components. In this study, we captured images of fractal patterns formed by chromosomal compartments and developed a theoretical model of their fractal dynamics. We showed that the nucleus behaves like a cavity, producing resonance effects similar to Chladni patterns. When the external agent, PCMS, interacts with this cavity, it generates a fractal pattern. We identified and mapped five key phase transitions that ultimately lead to the breakdown of cancer cell nuclei. Full article

As a key means to solve energy and environmental problems, photocatalytic technology has made remarkable progress in recent years. Organic semiconductor materials offer structural diversity and tunable energy levels and thus attracted great attention. Among them, porphyrin and its derivatives show great potential in photocatalytic reactions and light therapy due to their unique large-π conjugation structure, high apparent quantum efficiency, tailorable functionality, and excellent biocompatibility. Compared to unassembled porphyrin molecules, supramolecular porphyrin assemblies facilitate the solar light absorption and improve the charge transfer and thus exhibit enhanced photocatalytic performance. Herein, the research progress of porphyrin-based supramolecular assemblies, including the construction, the regulation of charge separation and transfer, stability, and application in photocatalysis, was systematically reviewed. The construction strategy of porphyrin supramolecules, the mechanism of charge separation, and the intrinsic relationship of assembling structure-charge transfer-photocatalytic performance received special attention. Surfactants, peptide molecules, polymers, and metal ions were introduced to improve the stability of the porphyrin assemblies. Donor-acceptor structure and co-catalysts were incorporated to inhibit the recombination of the photoinduced charges. These increase the understanding of the porphyrin supramolecules and provide ideas for the design of high-performance porphyrin-based photocatalysts. Full article

Photocatalytic degradation of organic pollutants is one of the green ways to solve environmental problems. In this study, the PDI-COOH/PDINH composite photocatalysts were successfully synthesized by electrostatic self-assembly. Under visible light irradiation, the degradation efficiency of the optimal PDI-COOH/PDINH sample reached 67%, which was 1.7 and 1.6 times higher than that of the self-assembled PDINH supramolecule and PDI-COOH supramolecule, respectively. The excellent photocatalytic performance of PDI-COOH/PDINH can be attributed to the enhancement of the separation and transport efficiency of photogenerated carriers by the construction of a heterojunction and the expanded electronic conjugated structure by the combination of organic–organic semiconductors. This study offers a new idea for the preparation of organic–organic composite photocatalysts. Full article

Isoamyl 4-methoxycinnamate (IMC) is widely used in various fields because of its exceptional UV-filter properties. However, due to its cytotoxicity and anti-microbial degradability, the potential eco-environmental toxicity of IMC has become a focus of attention. In this study, we propose a host–guest supramolecule approach to enhance the functionality of IMC, resulting in a more environmentally friendly and high-performance materials. Sulfobutyl-β-cyclodextrin sodium salt (SBE-β-CD) was used as the host molecule. IMC-SBE-β-CD supramolecular substances were prepared through the “saturated solution method”, and their properties and biosecurity were evaluated. Meanwhile, we conducted the AOS tree evaluation system that surpasses existing evaluation approaches based on apoptosis, oxidative stress system, and signaling pathways to investigate the toxicological mechanisms of IMC-SBE-β-CD within human hepatoma SMMC-7721 cells as model organisms. The AOS tree evaluation system aims to offer the comprehensive analysis of the cytotoxic effects of IMC-SBE-β-CD. Our findings showed that IMC-SBE-β-CD had an encapsulation rate of 84.45% and optimal stability at 30 °C. Further, IMC-SBE-β-CD promoted cell growth and reproduction without compromising the integrity of mitochondria and nucleus or disrupting oxidative stress and apoptosis-related pathways. Compared to IMC, IMC-SBE-β-CD is biologically safe and has improved water solubility with the UV absorption property maintained. Our study provides the foundation for the encapsulation of hydrophobic, low-toxicity organic compounds using cyclodextrins and offers valuable insights for future research in this field. Full article

Previous studies have found that the self-assembled supramolecules of Azumapecten farreri meat peptides have antioxidant effects. Therefore, this study aims to isolate and identify novel antioxidant peptides with self-assembly characteristics and analyze their structure–activity relationship through molecular docking and molecular dynamics simulation. The in vitro results show that as the purification steps increased, the antioxidant activity of peptides became stronger. Additionally, the purification step did not affect its pH-responsive self-assembly. Using LC-MS/MS, 298 peptide sequences were identified from the purified fraction PF1, and 12 safe and antioxidant-active peptides were acquired through in silico screening. The molecular docking results show that they had good binding interactions with key antioxidant-related protein ligands (KEAP1 (Kelch-like ECH-associated protein 1) and MPO (myeloperoxidase)). The peptide QPPALNDSYLYGPQ, with the lowest docking energy, was selected for a 100 ns molecular dynamics simulation. The results show that the peptide QPPALNDSYLYGPQ exhibited excellent stability when docked with KEAP1 and MPO, thus exerting antioxidant effects by regulating the KEAP1-NRF2 pathway and inhibiting MPO activity. This study further validates the antioxidant and self-assembling properties of the self-assembled supramolecules of Azumapecten farreri meat peptide and shows its potential for developing new, effective, and stable antioxidants. Full article

The organic–inorganic hybrid compound, (o-BrAH)[H₂Co(CN)₆]_0.5·(18-crown-6)_0.5·H₂O, was synthesized and characterized by variable-temperature X-ray diffraction, single-crystal diffraction, infrared spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and dielectric measurements. Single-crystal X-ray diffraction revealed a three-dimensional cage-like structure formed through the hydrogen bonds of cobalt hexacyanide, supermolecular cations, and water molecules. Temperature variation triggered an abrupt change in the cage structure and simultaneously caused dynamic oscillation of the supramolecules within the framework of [Co(CN)₆]₃⁻, inducing a phase transition accompanied by a step-like change in the dielectric physical properties. Full article

Humic substances are naturally occurring materials composed of complex biogenic mixtures of substituted aromatic and aliphatic hydrocarbon core materials derived from the degradation and decomposition of dead plant and animal matter. They are ubiquitous in both terrestrial and aquatic systems constituting biotic pools and are characterized by unique properties; they are amphiphilic redox compounds with exceptional chelating features. Humic substances play a crucial role in both agriculture and the environment as carbon sequestrators, soil improvers, plant health promoters, as well as stabilizers of soil aggregates and regulators of organic/inorganic nutrients bioavailability. This review article attempts to summarize current knowledge about the molecular nature and characterization techniques employed for the study of humic substances worldwide as the chemistry of their components differs markedly and depends on natural processes, several abiotic and biotic factors, the origin of the organic matter, and their complexation with inorganic, e.g., metal-ion, compounds. This work is equally concerned with the association of humic substances with dyes, a notorious pollutant, responsible for various environmental issues generally arising from the discharge of untreated effluents into soils and water bodies. Azo dyes, in particular, negatively affect soil microbial communities, as well as plant germination and growth. The aim is to feature the potential contribution of humic substances as novel materials for environment-friendly and sustainable processes. Full article

This review article presents the biomimetic helical inclusion of amylose toward hydrophobic polyesters as guests through a vine-twining polymerization process, which has been performed in the glucan phosphorylase (GP)-catalyzed enzymatic polymerization field to fabricate supramolecules and other nanostructured materials. Amylose, which is a representative abundant glucose polymer (polysaccharide) with left-handed helical conformation, is well known to include a number of hydrophobic guest molecules with suitable geometry and size in its cavity to construct helical inclusion complexes. Pure amylose is prepared through enzymatic polymerization of α-d-glucose 1-phosphate as a monomer using a maltooligosaccharide as a primer, catalyzed by GP. It is reported that the elongated amylosic chain at the nonreducing end in enzymatic polymerization twines around guest polymers with suitable structures and moderate hydrophobicity, which is dispersed in aqueous polymerization media, to form amylosic nanostructured inclusion complexes. As the image of this system is similar to how vines of a plant grow around a support rod, this polymerization has been named ‘vine-twining polymerization’. In particular, the helical inclusion behavior of the enzymatically produced amylose toward hydrophobic polyesters depending on their structures, e.g., chain lengths and substituents, has been systematically investigated in the vine-twining polymerization field. Furthermore, amylosic supramolecular network materials, such as hydrogels, are fabricated through vine-twining polymerization by using copolymers, where hydrophobic polyester guests or maltooligosaccharide primers are covalently modified on hydrophilic main-chain polymers. The vine-twining polymerization using such copolymers in the appropriate systems induces the formation of amylosic nanostructured inclusion complexes among them, which act as cross-linking points, giving rise to supramolecular networks at the nanoscale. The resulting materials form supramolecular hydrogels, films, and microparticles. Full article