Frontiers in Chemistry
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2020
·
IF 3.693
Ai Qiushuang,Fu Qiang,Liang Feng
Recognition tunneling technique owns the capability for investigating and characterizing molecules at single molecule level. Here, we investigated the conductance value of cucurbit[7]uril (CB[7]) and melphalan@CB[7] (Mel@CB[7]) complex molecular junctions by using recognition tunneling technique. The conductances of CB[7] and Mel@CB[7] with different pH values were studied in aqueous media as well as organic solvent. Both pH value and guest molecule have an impact on the conductance of CB[7] molecular junction. The conductances of CB[7] and Mel@CB[7] both showed slightly difference on the conductance under different measurement systems. This work extends the molecular conductance measurement to aqueous media and provides new insights of pH-responsive host-guest system for single molecule detection through electrical measurements.
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JOURNAL OF CHEMICAL RESEARCH
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2021
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IF 0.782
Jue Chen,Tengmei Gao,Yinxia Chang,Yanming Wei,Yonghui Wang
Folate (FA) plays a key role in the biosynthesis of amino acids, purines, and pyrimidines in the human body, and intracellular folate metabolism has become an attractive target of tumor chemotherapy. In this work, an inclusion interaction was found between FA and cucurbit[7]uril (CB[7]), and the formation of a CB[7]-FA 2:1 supramolecular inclusion complex was confirmed by fluorescence spectra, UV-Vis absorption spectroscopy, 1H NMR, and molecular modeling calculations. In addition, FA is generally determined through the indirect fluorescent method because it shows weak fluorescence in aqueous solution. Therefore, a simple, direct fluorescence probe method for rapidly measuring FA was investigated, and the linear equation of FA was ΔF = 14.691C + 37.366 within the concentration ranges of 0.82 ~ 18.31 µg mL–1. The proposed direct fluorescence method was applied to the determination of spiked plasma. We demonstrated that this method could provide an experimental basis for the targeted administration of the CB[7]-FA complex, and it could be extended as a promising fluorescence detection method for drugs in vivo.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2025
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IF 4.6
Pengnan Yao,Nan Ma,Jinming Kong,Gengzhi Sun,Xueji Zhang
MicroRNAs (miRNAs) are a class of endogenous, non-coding, single-stranded RNA molecules that are typically 20–25 nucleotides in length. The expression levels of miRNAs in blood, tissue, and other samples are characteristically altered in several disease states. The detection of miRNAs represents a promising avenue for the early diagnosis of various diseases. Consequently, there is a clear need to enhance the sensitivity of miRNA detection to facilitate more accurate disease detection. A fluorescent biosensor was developed that utilizes supramolecular host-guest interactions for assembly and Mo-based materials to initiate a reversible addition-fragmentation chain transfer polymerization (RAFT). The scheme functions by modifying the miRNA on Fe 3 O 4 -magnetic nanoparticles (Fe 3 O 4 -MNPs), followed by linking the initiator of the subsequent RAFT reaction through supramolecular host-guest interaction. Ultimately, polymerization reactions initiated by Mo compounds result in the formation of polymers with fluorescent monomers on Fe 3 O 4 -MNPs. The sensor is extremely sensitive and the detection limit of this sensor is 0.03 fM. Furthermore, the protocol has been demonstrated to be highly effective in the detection of samples in serum, which also serves to illustrate the potential of this fluorescent biosensor for the detection of other kinds of miRNAs.
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NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 43
·期 1
·407-412
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IF 3.201
Pei-Hui Shan,Zhi-Rui Zhang,Dong Bai,Bing Bian,Zhu Tao,Xin Xiao
The interactions between inverted cucurbit[7]uril (iQ[7]) and six biogenic amines, namely tyramine (TA), 2-phenylethylamine (PEA), histamine (HI), tryptamine (TR), spermine (SPM), and spermidine (SPD), were studied through 1H nuclear magnetic resonance (NMR) spectroscopy, UV/vis absorption spectroscopy, fluorescence spectroscopy, isothermal titration calorimetry (ITC), and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The results showed that iQ[7] exhibits binding affinity towards five of these biogenic amines, with the exception of HI, and that the host–guest binding sites differ depending on the structure of the biogenic amine. For the aromatic amines (TA and PEA), the phenyl groups are completely encapsulated within iQ[7]; for the heterocyclic aromatic amine TR, there is deep inclusion of its indole group in the cavity of iQ[7]; for the fatty amines (SPM and SPD), the central alkyl chain is bound within the central cavity of iQ[7].
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ChemPlusChem
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2020
·Vol. 85
·期 4
·679-683
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IF 2.753
Shengke Li,Kit Ieng Kuok,Xia Ji,Anni Xu,Hang Yin,Jun Zheng,Huaping Tan,Ruibing Wang
Graphical Antibacterial switch : The capability of cucurbit[7]uril (CB[7]) in modulating the antibacterial activity of ambroxol hydrochloride (ABX) was successfully demonstrated by using two strains of Pseudomonas aeruginosa and Escherichia coli . The antibacterial activity of ABX was “turned off” upon encapsulation by CB[7] and “turned on” after ABX was released from the CB[7]-ABX host–guest complex upon addition of a competitive guest amantadine hydrochloride. Supramolecular encapsulation by cucurbit[7]uril (CB[7]) was recently demonstrated to provide a simple and efficient method for antibacterial activity regulation of antibiotics. In this work, CB[7] was shown to form binary host-guest complex with ambroxol hydrochloride (ABX), a clinical mucokinetic and expectorant drug, which was reported to exhibit certain antibacterial activity. 1 H NMR titration and isothermal titration calorimetry experiment results suggested that the 4-hydroxyl cyclohexylamine group of ABX was included inside the CB[7] cavity, with a binding constant K a of (6.69±0.11)×10 5 M −1 in phosphate buffered saline (PBS) solution, thermodynamically driven by both enthalpy change (ΔH=−12.2 kJ/mol) and entropy change (TΔS=21.1 kJ/mol). More importantly, ABX's inhibitory activity (MIC 50 ) against bacillary strains towards Pseudomonas aeruginosa and Escherichia coli strains was decreased from (5.11±0.31)×10 −6 M −1 and (2.63±0.34)×10 −5 M −1 to zero upon encapsulation by CB[7], and was subsequently recovered to almost its original activity when a competitive guest, amantadine hydrochloride, for disassembling CB[7]-ABX complex, was added, suggesting that the antibacterial activity of ABX could be readily “turned off/on” upon its complexation and decomplexation with CB[7].
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JOURNAL OF CHROMATOGRAPHY A
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2014
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IF 4.258
Liyun Ma,Si-Min Liu,Lin Yao,Li Xu
Cucurbit[7]uril (CB7), one host macromolecule, possesses a hydrophobic inner cavity and two identical hydrophilic carbonyl fringe portals, thus interacting with a variety of guest molecules through hydrophobic, hydrogen bonding and ion–dipole interactions. These characteristics make CB7 a good candidate as the stationary phase (SP) modifier in high performance liquid chromatography (HPLC). In the present work, CB7 was immobilized onto silica (CB7-SiO 2 ) by a sol–gel approach. The obtained CB7-SiO 2 was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and elemental analysis. The chromatographic performance of CB7-SiO 2 was then studied in detail, in both reversed phase (RP) and hydrophilic interaction liquid chromatographic (HILIC) modes. For probe aromatic compounds and dyes, the typical RP behavior was observed, mainly due to the predominant hydrophobic interaction between the analytes and CB7-SiO 2 . For probe alkaloids, the “U-shape” curves were obtained; in the methanol-rich part, HILIC performance was obvious, probably owing to hydrogen bonding and ion–dipole interactions. Compared to bare SiO 2 SP, the stronger retention and different selectivity were observed on CB7-SiO 2 . The CB7-SiO 2 SP remained stable within at least 11,000 column volumes of the MP, revealing the satisfactory stability of it. The proposed method integrated the advantages of CB7 and sol–gel method provided a feasible way for the wider application of CBs in separation science.
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ANALYTICA CHIMICA ACTA
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2026
·
IF 6.1
Nurimangul Muntiza,Qun Wang,Yanan Liu,Jiayi Wang,Xuejia Chang,Meifang Xiao,Boyu Yuan,Qinran Li,Haijie Li,Yanjun Yu,Qiliang Deng
Developing highly fluorescent COFs represents a challenging task due to their aggregation-caused quenching effect. In this research, highly fluorescent COFs were successfully constructed by introducing Q[7] as a macrocyclic framework unit into their backbone via a mechanical interlocking strategy. These Q[7]-based polycyclic COFs exhibited fluorescence quantum yields that were 10 times higher than those of their Q[7]-free counterparts, owing to the weakened interlayer aggregation and the cavity confinement effect of Q[7]. The recognition sites from Q[7] and also endowed these Q[7]-based polycyclic COFs with a prominent fluorescence response to various targets. These prominent properties enable COFs as a sensor array for highly sensitive identification and detection of 13 sulfonamide antibiotics (SAs) with detection limits down to the nanomolar range, with recovery rates of 90.3%–104.7% in real samples. The supramolecular isolation strategy and cavity confinement effect caused by Q[7] will drive increased interest in fabricating COFs using macrocyclic molecules.
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CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Hong-Si Guo,Wenfeng Zhao,Qingmei Ge,Nan Jiang,Mao Liu,Hang Cong
A promising method for producing hydrogen from solar energy and converting it into chemical fuels is photoelectrochemical (PEC) water splitting. In this paper, a novel photoanode is prepared by hydrothermal growing of nanorod CdS/g-C 3 N 4 /Q[7] heterojunction on FTO substrate for photoelectrochemical water splitting to produce hydrogen. In this method, Q[7]-doped g-C 3 N 4 is tightly combined with CdS composite and substrate, which significantly improves the separation and migration of photogenerated carriers in g-C 3 N 4 /Q[7] and CdS, and effectively reduces the internal resistance of the photoanode. Compared with the free CdS NRs, the PEC performance of the heterojunction CdS/g-C 3 N 4 /Q[7]-10 is significantly enhanced with the improved photocurrent density of 1049.7 μA/cm 2 under AM 1.5 G (100 mW/cm 2 ) simulated sunlight, which is 3.6 times that of pristine CdS and 2.6 times that of FTO-CdS/g-C 3 N 4 under the same conditions. The external bias photocurrent conversion efficiency and photohydrogen conversion efficiency of CdS/g-C 3 N 4 /Q[7]-10 photoanode at 0.7 V (relative to RHE) are measured to be both 0.31 %, as 3.1 times high as that of the original CdS NRs (0.10 %), and 2.07 times high as that of FTO-CdS/g-C 3 N 4 (0.15 %). The generation of heterostructure with interfacial interaction reduces the recombination of photogenerated electron-hole pairs, to enhance the charge transfer of water oxidation kinetics, allowing electrons to quickly transfer through the external circuit to the counter electrode for H + reduction to produce H 2 . A schematic diagram of the photoelectrochemical water splitting hydrogen evolution process with the heterojunction CdS/g-C 3 N 4 /Q[7]-10 is systematically proposed.
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SUPRAMOLECULAR CHEMISTRY
·
2019
·
IF 1.66
Danhong Yan,Xiangyang Miao,Ronghua Ma,Huashan Yao,Jinlong Li,Ya Cao
Herein, we develop a switchable peptide-equipped protein/cucurbit[7]uril (CB[7]) supramolecular assembly as novel targeted drug vector. Specifically, bovine serum albumin (BSA) is used to interact with CB[7], serving as the core of drug vector. Then, a peptide shield layer is formed on the surface of BSA/CB[7], yielding peptide-equipped supramolecular assembly (Pep@BSA@CB[7]). The equipped peptide shield layer is composed of switchable peptide probes consisting of a polycationic cell-penetrating peptide (CPP) motif, a polyanionic motif and a linking motif, and therefore provides a variety of desirable properties. First, the CPP motif displays excellent cell penetration ability and can facilitate internalisation of the drug vector. Secondly, the polyanionic motif performs intramolecular electrostatic interaction with CPP motif and thereby can reduce non-targeted delivery towards normal cells. Thirdly, the linking motif can be specifically cleaved by matrix metalloproteinases 2 that is up-regulated in tumour microenvironment, thus enabling precise cancer-targeting. As a consequent, Pep@BSA@CB[7] can serve as a promising drug vector that exhibits superior targeting ability and high uptake efficiency towards cancer cells, which may be of great potential in cancer-targeted treatment.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2025
·
IF 2.8
Lei Zou,Jiajun Ren,Fangdong Ning,Xianmei Ma,Matthew J. Webber,Yongjun Zhang
Slide-ring hydrogels have been shown to have exceptional toughness and stretchability. Current designs typically rely on polyrotaxane architectures of cyclodextrin (CD) macrocycles treaded onto polyethylene glycol (PEG) chains. The use of alternative macrocycles to prepare slide-ring hydrogels remains largely unexplored. In this study, we present a cucurbit[7]uril (CB[7]) slide-ring hydrogel prepared from multiblock PEG polymers segmented with guest moieties of varying affinity for binding to CB[7]. Following threading with allyl-modified CB[7] to form pseudopolyrotaxane structures, the side-chains are then covalently cross-linked to yield the slide-ring architecture. The resulting hydrogels exhibit unique mechanical properties modulated by host–guest binding affinity and dynamics. Given the exceptional molecular recognition capabilities of the CB[n] family of macrocycles for diverse guests, using these as alternatives to CDs offers an opportunity to expand the design space for slide-ring hydrogel architectures.
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Advanced Healthcare Materials
·
2018
·Vol. 8
·期 2
·1801458
·
IF 5.609
Haishi Qiao,Jing Jia,Wei Chen,Bin Di,Oren A. Scherman,Chi Hu
The fabrication, characterization, and therapy efficiency of a noncovalent-bonded hydrogel network, which is assembled by utilizing cucurbit[7]uril as a supramolecular linker to “stick” superparamagnetic γ-Fe 2 O 3 nanoparticles onto the polymer backbone of catechol-functionalized chitosan are described. The unique barrel-shaped structure of cucurbit[7]uril not only facilitates host–guest recognition with the catechol derivatives, but also forms robust electrostatic interactions between its carbonyl portals and the γ-Fe 2 O 3 nanoparticles in a supramolecular manner, which leaves the physical and chemical properties of the nanoparticles intact. The γ-Fe 2 O 3 nanoparticles display vibrational movement and heat generation under an alternating magnetic field, endowing the formed hybrid supramolecular hydrogel with both thermo- and chemotherapy modalities, which are demonstrated both in vitro and in vivo. Here, a facile strategy is introduced to construct noncovalent interactions between a polymer matrix and the incorporated nanoparticles, which is amendable to a wide range of biomedical and industrial applications.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2021
·
IF 4.098
Qin Wang,Li-Bing Lü,Zhu Tao,Tao Sun,Qing Tang,Ying Huang
In the present work, we have investigated the effect of pH and mercury ions on the host–guest complex formed between cucurbit[7]uril (Q[7]) and Hoechst 33342 (H33342). 1 H NMR, UV–vis and fluorescence spectroscopy revealed that acid/base stimulation could change the binding stoichiometry between Q[7] and H33342. The results suggest that two complexation equilibria (1:1 and 2:1) may exist between H33342 and Q[7] at pH 2.0 and 4.5, respectively. However, a 1:1 host–guest complex was formed between H33342 and Q[7] at pH 7.0 and 10.0. Q[7] shows differential affinities for the protonated and neutral forms of H33342 dye. Moreover, the switching between H33342∙2H + @2Q[7](1:2) at pH 4.5 and H33342∙H + @Q[7](1:1) at pH 7.0 was reversible. Furthermore, as a metal stimulus, Hg 2+ ions could push (i) Q[7] from the piperazine ring to the benzimidazole position with a 1:1 guest–host ratio and (ii) a second Q[7] onto the ethyl position with a 1:2 guest–host stoichiometry. This stimulus response system will have potential applications in the field of molecular switch design.
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