Β-cyclodextrin Cavity Research Articles

High-efficiency gold recovery by additive-induced supramolecular polymerization of β-cyclodextrin

Developing an eco-friendly, efficient, and highly selective gold-recovery technology is urgently needed in order to maintain sustainable environments and improve the utilization of resources. Here we report an additive-induced gold recovery paradigm based on precisely controlling the reciprocal transformation and instantaneous assembly of the second-sphere coordinated adducts formed between β-cyclodextrin and tetrabromoaurate anions. The additives initiate a rapid assembly process by co-occupying the binding cavity of β-cyclodextrin along with the tetrabromoaurate anions, leading to the formation of supramolecular polymers that precipitate from aqueous solutions as cocrystals. The efficiency of gold recovery reaches 99.8% when dibutyl carbitol is deployed as the additive. This cocrystallization is highly selective for square-planar tetrabromoaurate anions. In a laboratory-scale gold-recovery protocol, over 94% of gold in electronic waste was recovered at gold concentrations as low as 9.3 ppm. This simple protocol constitutes a promising paradigm for the sustainable recovery of gold, featuring reduced energy consumption, low cost inputs, and the avoidance of environmental pollution.

Cyclodextrin-functionalized magnetic alginate microspheres for synchronous removal of lead and bisphenol a from contaminated soil

Currently, functional materials-based soil remediation focused on the stabilization of heavy metals and organics to inhibit their migration, however, the possible second release of these pollutants caused by soil condition variation attracts broad attention. Herein, β-cyclodextrin functionalized magnetic sodium alginate microspheres (MSA-CDMW) were fast and facilely synthesized through microwave-assisted one-pot method for synchronous detachment of Pb and BPA from contaminated soil. The obtained MSA-CDMW presented wide pH adaptability and fast capture for Pb(II)/BPA with superior adsorption capacity of 369.03/165.37 mg/g. Furthermore, the effects of material dosage and soil pH on the remediation ability of MSA-CDMW were explored in detail. After adding 5% MSA-CDMW into the contaminated soil for 3-round successive remediation (12 h for each round), the amount of extractable Pb and total BPA was simultaneously decreased by 56.30 and 0.78 mg/kg, respectively. Meanwhile, the quantity of exchangeable and carbonate bound Pb was significantly decreased to 7.13% with transformation into relatively stable fractions. A series of characterizations revealed that ion exchange, pore filling, complexation, and electrostatic attraction were responsible for Pb binding, while MSA-CDMW could capture BPA through host-guest interaction by the hydrophobic cavity of β-cyclodextrin. Additionally, recovery and floatation results revealed that the MSA-CDMW could be easily separated from the soil using magnets even at extreme drying and wetting conditions, thus providing a novel, fast, and eco-friendly strategy for effective remediation of heavy metals and organics contaminated soil.

Preparation and application of cinnamon-Litsea cubeba compound essential oil microcapsules for peanut kernel postharvest storage

This research developed a novel, efficient and safe antimildew for peanut kernel postharvest storage. The antimildew, cinnamon-Litsea cubeba compound essential oil (CLCEO) microcapsule (CLCEOM), was synthesized with CLCEO as core materials and β-cyclodextrin as wall materials. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry analyses indicated that major antifungal compounds of CLCEO were encapsulated in the cavity of β-cyclodextrin. The inhibition zone experiment showed that CLCEOM retained antifungal effect on Aspergillus spp. strains even after storage for 2 months at 4 ℃. Besides, CLCEOM reduced total number of fungal colonies, relative abundance of Aspergillus spp., and aflatoxin B1 content of peanut kernels, and had positive effect on slowing down the increase in acid value of peanut oil without causing any adverse effect on the viability and sensory properties during storage process. Overall, CLCEOM presented good preservative effects on peanut kernels, providing evidence for its potential use as antimildew for peanut storage.

Binary and ternary inclusion complexation of lapatinib ditosylate with β-cyclodextrin: preparation, evaluation and in vitro anticancer activity

BackgroundLapatinib ditosylate, an efficient tyrosine kinase inhibitor for breast cancer, poses pharmacokinetic issues, hence developing its oral delivery system is troublesome. The poor aqueous solubility of this medicament is a key impediment in developing its successful formulation. So, the current study aims to improve water solubility of Lapatinib ditosylate by using complexation technique with β-cyclodextrin and a suitable ternary agent.ResultsBinary and ternary complexes of Lapatinib ditosylate were synthesized by means of kneading and lyophilization using β-cyclodextrin and PVP K30. As a ternary agent, various hydrophilic polymers, as well as organic acids, were assessed, and PVP K30 was chosen for the final formulation based on its stability constant and complexation efficiency. When compared to pure Lapatinib ditosylate, both inclusion complexes demonstrated improved solubility, and drug dissolution. Differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), Fourier transform infrared (FTIR), and scanning electron microscopic (SEM) techniques, all validated the complex formation. Docking studies picturized the geometry of Lapatinib ditosylate in β-cyclodextrin cavity. Using MCF-7 cell lines, investigation of anticancer activity of the pure drug and its synthesized complexes was carried out and the results revealed that the complexes had stronger anticancer activity than Lapatinib ditosylate alone.ConclusionsOverall, it can be concluded that Lapatinib ditosylate complexation increased its aqueous solubility, resulting in its increased dissolution and in vitro anticancer activity in a breast cancer cell line.

Bioactivity and Cell Imaging of Antitumor Fluorescent Agents (Curcumin Derivatives) Coated by Two-Way Embedded Cyclodextrin Strategy.

Curcumin has a wide range of pharmacological activities, which can be used to treat tumors, inflammation and other diseases. However, curcumin's poor solubility and low bioavailability limit its application. In this article, the structure of curcumin was modified with boron trifluoride ether to change fluorescent labeling. The compounds were then embedded into the hydrophobic cavity of α-cyclodextrin and hydroxypropyl β-cyclodextrin to form inclusion complexes. The two inclusion complexes have excellent photophysical properties, and the maximum emission wavelength is in the range of 550-565 nm. In addition, the two compounds were applied to the fluorescence imaging of HCT-116 cells and HeLa cells, and the proliferation toxicity of the compounds was detected. Both compounds showed certain inhibitory effects on the proliferation of cancer cells. In short, the fluorescent drug molecule synthesized in this article has great reference value for the development of new dosage forms of curcumin.

‘On and Off’ intercalative binding behaviour of double chain surfactant cobalt(III) complex containing 2, 2′-bipyridyl ligand in β-Cyclodextrin: A detail approach on Host-guest inclusion of surfactant cobalt(III) complex and CT-DNA binding in micro-heterogeneous medium

The binding interaction of surfactant cobalt(III) complex, cis-[Co(bpy)2(HA)2](ClO4)3, in which bpy is 2,2-bipyridine and HA is hexadecylamine or cetylamnine with DNA was through intercalative mode via the long aliphatic chains present in the ligands. The binding was investigated by various techniques, electronic absorption, fluorescence spectroscopy, circular dichroism (CD), cyclic voltametry (CV) and viscosimetry measurements. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that the surfactant cobalt(III) complex binds to calf thymus DNA by intercalation through the aliphatic chain present in the complex into the base pairs of DNA. The presence of bipyridine ligand with larger π-frame work may also enhance intercalation. UV–vis., spectrum showed 4 nm bathochromic shift of the absorption band at 352 nm along with significant hypochromicity for the absorption band of the complex. The intrinsic binding constants(at below and above CMC are Kb = 2.41 × 105M−1, Kb = 3.12 × 106M−1 respectively) is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the surfactant cobalt(III) complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. Competitive binding study with ethidium bromide (EB) shows that the surfactant complex exhibits the ability to displace the DNA-bound EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed. Besides the effect of binding of surfactant cobalt(III) complex to DNA in presence of β-cyclodextrin has also studied. This binding of the surfactant cobalt(III) complex in presence of β-cyclodextrin medium has been prevented (at below and above CMC are Kb = 5.45 × 104M−1, Kb = 6.92 × 105M−1 respectively) due to the incorporation of the aliphatic chains into the cavity of β-cyclodextrin. In presence of β-cyclodextrin the binding occur through surface and (or) groove binding can be attributed to the inclusion of the long aliphatic chain that is present in one of the ligands into cyclodextrin.

Modified β-cyclodextrins: Rosmarinic acid inclusion complexes as functional food ingredients show improved operations (solubility, stability and antioxidant activity)

The objective of our study is to investigate rosmarinic acid (RoA) functionalities (antioxidant activity) and eliminate practical limitations (bitter taste, poor solubility, and low stability) when included in two modified β-cyclodextrin cavities (2-HP & AC)-β-CyD. The binding 1: 1 stoichiometry of (2-HP & AC)-β-CyD: RoA inclusion complexes (ICs) were prepared with AL type solubility as an enthalpy-driven process and recognized by various experimental methods. All molecular docking and molecular dynamic simulation results indicated that accompanying one and two hydrogen bonds, van der Waals interactions play a significant role in the inclusion of RoA into modified β-CyD cavities. These methods proved that the 2-HP-β-CyD: RoA IC is more stable than AC- β-CyD: RoA IC. Finally, the effect of modified β-CDs on photo- and chemical stability of RoA monitored can be interesting in its potential application as a food supplement with antioxidant activity and lowering the risk of cancers and heart disease.

ENCAPSULATION OF EXEMESTANE WITH β-CYCLODEXTRIN AND TERNARY AGENT: FORMULATION, EVALUATION AND ANTICANCER ACTIVITY

Objective: A potent aromatase inhibitor, Exemestane, is well known for its anticancer action in breast neoplasm. The vital problem of this medicament is its poor aqueous solubility, which hinders its dissolution in body fluids. Therefore, the present study targets to enhance the water solubility of Exemestane by means of its complexation with β-cyclodextrin and a suitable ternary agent. Methods: Inclusion complexes of Exemestane with β-cyclodextrin and ternary agent were prepared by kneading and lyophilization technique. Different hydrophilic polymers and organic acids were screened for their influential ability as a co-complex with a carrier; β-cyclodextrin. The validation of complex formation was carried out by various solid-state techniques. The geometry of Exemestane in the β-cyclodextrin cavity was picturized in docking studies. The in vitro anticancer activity of prepared inclusion complex formulations carried out using MCF-7 cell lines Results: Phase solubility analysis proved HPMC E5 as the best ternary agent for complexation of Exemestane with β-cyclodextrin as it improved the stability constant of the drug from 665.92 M-1 to 1238.38 M-1. The synthesized binary and ternary inclusion complexes exhibited 2.74 and 4.62 times enhanced solubilization of Exemestane. Likewise, the dissolution characteristics of Exemestane were improved, and drug release was increased by 1.18 and 1.42 times with binary and ternary freeze-dried formulations. Differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) study results presented the formation of binary and ternary complexes with significantly drooped crystallinity. Docking studies predicted encapsulation of rings A, B, and C of Exemestane in the cavity of β-cyclodextrin. In-line results were obtained in Fourier transform infrared (FTIR) studies. The cell growth inhibition of 62.78 % was achieved with a ternary complex of Exemestane which was far superior than the pure active moiety that showed mere 44.56 % of inhibition. Conclusion: Altogether, it can be concluded that the inclusion complex of Exemestane boosted its aqueous solubility, resulting in its increased dissolution and in vitro anticancer activity in a breast cancer MCF-7 cell line.

Noncovalent Polymerization-Activated Ultrastrong Near-Infrared Room-Temperature Phosphorescence Energy Transfer Assembly in Aqueous Solution.

Noncovalent macrocycle-confined supramolecular purely organic room-temperature phosphorescence (RTP) is a current research hotspot. Herein, a high-efficiency noncovalent polymerization-activated near-infrared (NIR)-emissive RTP-harvesting system in aqueous solution based on the stepwise confinement of cucurbit[7]uril (CB[7]) and β-cyclodextrin-grafted hyaluronic acid (HACD), is reported. Compared with the dodecyl-chain-bridged 6-bromoisoquinoline derivative (G), the dumbbell-shaped assembly G⊂CB[7] presents an appeared complexation-induced RTP signal at 540nm via the first confinement of CB[7]. Subsequently, benefitting from the stepwise confinement encapsulation of the β-cyclodextrin cavity, the subsequent noncovalent polymerization of the binary G⊂CB[7] assembly enabled by HACD can contribute to the further-enhanced RTP emission intensity approximately eighttimes in addition to an increased lifetime from 59.0µs to 0.581ms. Moreover, upon doping a small amount of two types of organic dyes, Nile blue or tetrakis(4-sulfophenyl)porphyrin as an acceptor into the supramolecular confinement assembly G⊂CB[7] @ HACD, efficient RTP energy transfer occurs accompanied by a long-lived NIR-emitting performance (680 and 710nm) with a high donor/acceptor ratio. Intriguingly, the prepared RTP-harvesting system is successfully applied for targeted NIR imaging of living tumor cells by utilizing the targeting ability of hyaluronic acid, which provides a new strategy to create advanced water-soluble NIR phosphorescent materials.

L-Arginine-Derived Polyamidoamine Oligomers Bearing at Both Ends β-Cyclodextrin Units as pH-Sensitive Curcumin Carriers.

The aza-Michael polyaddition of L-arginine and N,N′-methylene-bis-acrylamide gives the biocompatible and easily cell-internalized polyamidoamine ARGO7. By controlled synthesis, two ARGO7 oligomers, namely a trimer and a pentamer, bearing acrylamide terminal units, were obtained as precursors of the β-cyclodextrin-end-terminated oligomers P3 and P5, which have been shown to encapsulate curcumin at both pH 7.4 and 4.5. After lyophilization, P3- and P5-curcumin complexes gave stable water solutions. The apparent solubility of encapsulated curcumin was in the range 20–51 μg mL−1, that is, three orders of magnitude higher than the water solubility of free curcumin (0.011 μg mL−1). The drug release profiles showed induction periods both at pH levels 4.5 and 7.4, suggesting a diffusive release mechanism, as confirmed by kinetic studies. The release rate of curcumin was higher at pH 7.4 than at pH 4.5 and, in both cases, it was higher for the P5 complex. Encapsulated curcumin was more photostable than the free drug. Molecular mechanics and molecular dynamics simulations explain at atomistic level the formation of aggregates due to favorable van der Waals interactions. The drug molecules interact with the external surface of carriers or form inclusion complexes with the β-cyclodextrin cavities. The aggregate stability is higher at pH 4.5.

(-)-Menthol-β-cyclodextrin inclusion complex production and characterization

Abstract (-)-Menthol has been widely used in clinical medicine, flavor, and fragrance. However, high volatility, short retention time, low solubility in water, and whisker growth of menthol are crucial problems for its application. In this paper, (-)-menthol-β-cyclodextrin inclusion complex was fabricated to solve these problems. The product was characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The results showed that menthol was successfully encapsulated in the cavity of β-cyclodextrin. Menthol itself vaporized almost completely at around 120 oC, while the maximum menthol release rate occurred at 267.5 oC after the formation of the inclusion complex. The stability and retention time were improved. The menthol release reaction order, apparent activation energy and the pre-exponential factor were obtained and their values were 0, 142.9 kJ/mol and 1.6 × 1013 respectively. The structure of menthol-β-cyclodextrin inclusion complex was investigated by molecular simulation and the minimum energy, –116.7 kJ/mol, was obtained at –0.8 × 10–10 m.

β-cyclodextrin microencapsulation enhanced antioxidant and antihyperlipidemic properties of Tunisian Periploca angustifolia roots condensed tannins in rats.

This study aimed to investigate the microencapsulation of novel condensed tannins isolated from Periploca angustifolia roots, using β-cyclodextrin macrocyclic oligosaccharides, in order to enhance their antioxidant and antihyperlipidemic potentials. Scanning electron microscopy and Fourier transform infrared spectroscopy results revealed that tannin fraction was successfully included into β-cyclodextrin cavities proved with an encapsulation efficacy of 70%. Our in vitro findings highlighted that both pure and encapsulated tannins have efficient inhibition capacities of pancreatic lipase activity. However, the inclusion complex has the greatest, in vivo, antioxidant, and antihyperlipidemic effects. In fact, results showed that complexed tannins had markedly restored serum lipid biomarkers, lipid peroxidation, protein carbonyl oxidation, and antioxidant enzyme defense. These findings were additionally confirmed by aortic and myocardial muscle sections of histological examination. Consequently, β-cyclodextrin microencapsulation may be considered as an effective and promising technique for tannin delivery with improved antioxidant and antihyperlipidemic activities.

Competitive Self-Assembly Interaction between Ferrocenyl Units and Amino Acids for Entry into the Cavity of β-Cyclodextrin for Chiral Electroanalysis.

At present, chiral electroanalysis of nonelectroactive chiral compounds still remains a challenge because they cannot provide an electrochemical signal by themselves. Here, a strategy based on a competitive self-assembly interaction of a ferrocene (Fc) unit and the testing isomers entering into the cavity of β-cyclodextrin (β-CD) was carried out for chiral electroanalysis. First of all, the Fc derivative was directly bridged to silica microspheres, followed by inclusion into the cavity of β-CD. As expected, once it was modified onto the surface of a carbon working electrode as an electrochemical sensor, SiO2@Fc-CD-WE, its differential pulse voltammetry signal would markedly decrease compared with the uncovered Fc. Next, when l- and d-isomers of amino acids that included histidine, threonine, phenylalanine, and glutamic acid were examined using SiO2@Fc-CD-WE, it showed an enantioselective entry of amino acids into the cavity of β-cyclodextrin instead of Fc, resulting in the release of Fc with signal enhancement. For histidine, glutamic acid, and threonine, l-isomers showed a higher peak current response compared with d-isomers. The peak current ratios between l- and d-isomers were 2.88, 1.21, and 1.40, respectively. At the same time, the opposite phenomenon occurred for phenylalanine with a peak current ratio of 3.19 between d- and l-isomers. In summary, we are assured that the recognition strategy based on the supramolecular interaction can enlarge the detection range of chiral compounds by electrochemical analysis.

β-cyclodextrin encapsulation of curcumin elicits an altered mode of angiogenin inhibition: In vitro and in vivo studies

The interaction of curcumin (Cur) with human angiogenin (hAng), a potent blood vessel inducer responsible for angiogenesis is found to change following encapsulation within the β-cyclodextrin (βCD) cavity. The enhanced bioavailability and increase in the binding stoichiometry of hAng:Cur-βCD (1:2) leads to increased affinity, hence an increase in the association constant. The altered mode of hAng inhibition of Cur from a non-competitive (KI = 23.7 ± 2.2 μM) to a mixed type (KI = 19.8 ± 1.4 μM), after encapsulation provides an insight into interaction patterns. Isothermal titration calorimetry (ITC) experiments indicate the formation of multiple favorable non-covalent interactions (also confirmed by docking studies), which implies negative enthalpy changes (−ΔHo) and restriction in the dynamic mobility of the free protein molecule resulting in a very less positive entropy change (TΔSo). This leads to a medium magnitude for the spontaneous free energy change associated with the interaction/binding process. The spontaneity of binding indicates a more favorable value for the Cur-βCD (ΔGo = −7.75 kcal/mol) compared to Cur (ΔGo = −7.49 kcal/mol). In vivo studies also demonstrate the anti-angiogenic effect of Cur/Cur-βCD confirmed by the significant decrease in blood vessel density and branching index.

Green synthesis and chemometric characterization of hydrophobic xanthan matrices: Interactions with phenolic compounds

Polysaccharides such as xanthan, locust bean gum or chitosan are easily crosslinked and purified using citric acid in an ecofriendly process. In order to achieve an improved sorption capability towards hydrophobic solutes, β-cyclodextrin, a cyclic oligosaccharide, and lignin, a natural aromatic polymer, are incorporated in the same process. Once crosslinked, the influence of these on the sorption capacities towards model solutes has been assessed by comparing the sorption isotherms of matrices with or without the hydrophobic modifications. The sorption capacities of these materials for different phenolic compounds have also been tested to ascertain their efficiencies as a function of their affinities to β-cyclodextrin cavities and/or their partition coefficients. In addition, these functionalized carbohydrate matrices were successfully characterized by principal component analysis, which is a useful tool to select the most appropriate polymers to interact with a specific molecule.

Molecular encapsulation by eosin yellow-β-cyclodextrin conjugate: Differential binding to quadruplex and duplex DNA

G-Quadruplexes exist in cells and are involved in several cancer-related processes. Thus, G-quadruplex binding is an effective way of aiming at cancer cells. In this paper, the binding of a new β-cyclodextrin conjugate, eosin yellow-CD, with quadruplex DNAs viz., kit22, myc22, telo24 and duplex calf-thymus DNA, is studied by UV–vis and fluorescence spectroscopic methods. Berberine, a known G-quadruplex binder, is loaded in the modified cyclodextrin. The binding constant of the host: guest complex is 1.9 × 106 mol−1 dm3. The proximity of the protons of the conjugate and Berberine with those of the internal cavity of β-cyclodextrin in the conjugate is confirmed by two-dimensional rotating-frame Overhauser effect spectroscopy. The conjugate displays a quenching of fluorescence selectively to the quadruplex kit22 and telo24 that contrasts the spectral characteristics of the ligand-bound complexes of myc22 and ctDNA. The Stern-Volmer quenching constants are 1.08 × 106 mol−1 dm3 and 1.6 × 106 mol−1 dm3, respectively for binding to kit22 and telo24. The duplex ctDNA exhibits an enhanced fluorescence in the absence and the presence of Berberine complex, whereas the quadrulex DNAs exhibit dissimilar emission profiles when the eosin yellow-CD encapsulates Berberine. We report the differences in the binding constants and the mode of binding of free- and Berberine-loaded eosin yellow-CD to the duplex and quadruplex DNAs.

Hydrophobic Localized Enrichment of Co-reactants to Enhance Electrochemiluminescence of Conjugated Polymers for Detecting SARS-CoV-2 Nucleocapsid Proteins.

The enrichment of co-reactants is one of the keys to improving the sensitivity of electrochemiluminescence (ECL) detection. This work developed a novel hydrophobic localized enrichment strategy of co-reactants utilizing the inner hydrophobic cavity of β-cyclodextrin (β-CD). Pt nanoparticles (Pt NPs) were grown in situ on the coordination sites for metal ions of β-CD to prepare the β-CD-Pt nanocomposite, which could not only enrich co-reactant 3-(dibutylamino) propylamine (TDBA) highly efficiently through its hydrophobic cavity but also immobilize TDBA via the Pt–N bond. Meanwhile, the carboxyl-functionalized poly[2,5-dioctyl-1,4-phenylene] (PDP) polymer nanoparticles (PNPs) were developed as excellent ECL luminophores. With SARS-CoV-2 nucleocapsid protein (ncovNP) as a model protein, the TDBA-β-CD-Pt nanocomposite combined PDP PNPs to construct a biosensor for ncovNP determination. The PDP PNPs were modified onto the surface of a glassy carbon electrode (GCE) to capture the first antibody (Ab1) and further capture antigen and secondary antibody complexes (TDBA-β-CD-Pt@Ab2). The resultant biosensor with a sandwich structure achieved a highly sensitive detection of ncovNP with a detection limit of 22 fg/mL. TDBA-β-CD-Pt shared with an inspiration in hydrophobic localized enrichment of co-reactants for improving the sensitivity of ECL detection. The luminophore PDP PNPs integrated TDBA-β-CD-Pt to provide a promising and sensitive ECL platform, offering a new method for ncovNP detection.

Controlled release and antibacterial properties of PEO/casein nanofibers loaded with Thymol/β-cyclodextrin inclusion complexes in beef preservation

There are still many limitations in the application of natural active compounds in meat preservation. Herein, thymol was first inserted into the cavity of β-cyclodextrin (β-CD) to form a stable inclusion complex (THY/β-CD-IC). The computational investigation showed that the optimized complexation energy for THY/β-CD-IC was −12.95 kcal mol−1. It contributed to the improvement of the thermal stability of thymol in the inclusion compound. Furthermore, the functionalized nanofibers (THY/β-CD-IC-NFs) loaded with THY/β-CD-IC were successfully fabricated by electrospinning of the mixture of casein and polyethylene oxide. When dealing with protease-producing bacteria, controllable release of thymol from THY/β-CD-IC-NFs was achieved through the response of casein to the hydrolysis of bacterial protease. The application results indicated that the prepared THY/β-CD-IC-NFs had a long-term antimicrobial activity for chilled beef preservation during 7-days storage. The information from this study presents a feasible strategy for the development of natural extracts for use in meat preservation.

Cationic cyclodextrin-adamantane poly(vinyl alcohol)-poly(ethylene glycol) assembly for siRNA delivery

In this research, the inclusion complex of cationic β-cyclodextrins (bcd) and adamantane (Ad) conjugated poly (vinyl alcohol), PVA, containing a poly (ethylene glycol) (PEG) polymer or Ad-PVA-PEG has been designed and synthesized as a siRNA carrier. Three different amino groups, i.e., putrescine, spermidine, and spermine substituted β-cyclodextrin (bcd1-3), were prepared. Their chemical structures were confirmed by 1H NMR and mass analysis. PVA was substituted by 4-hydroxy benzaldehyde connected to adamantane, which can fit in the β-cyclodextrin cavity. PEG was attached to the PVA chain. From the experiments, three cationic β-cyclodextrins can form the spherical nanoparticles with siRNA and Ad-PVA-PEG, as confirmed by 1H NMR and SEM analysis. The nanoparticles of Ad-PVA-PEG and bcd1-3 with various ratios have been studied, including the siRNA binding efficiency using gel electrophoresis. The nanoparticle size and zeta potential were investigated by using dynamic light scattering (DLS). It was found that the average size of the particles was less than 300 nm in range with the negative zeta potential buffer pH 7.4. In vitro evaluation showed that the siRNA nanoparticles knocked down GFP expression in A549 cells. The cytotoxicity test of siRNA nanoparticles show the same trend with Lipofectamine® 2000. Therefore, the self-assembly cationic bcd with Ad-PVA-PEG containing siRNA was a safe and efficient system for siRNA delivery.

A Dispersion Corrected DFT Investigation of the Inclusion Complexation of Dexamethasone with β-Cyclodextrin and Molecular Docking Study of Its Potential Activity against COVID-19.

The encapsulation mode of dexamethasone (Dex) into the cavity of β-cyclodextrin (β-CD), as well as its potential as an inhibitor of the COVID-19 main protease, were investigated using density functional theory with the recent dispersion corrections D4 and molecular docking calculations. Independent gradient model and natural bond orbital approaches allowed for the characterization of the host–guest interactions in the studied systems. Structural and energetic computation results revealed that hydrogen bonds and van der Waals interactions played significant roles in the stabilization of the formed Dex@β-CD complex. The complexation energy significantly decreased from −179.50 kJ/mol in the gas phase to −74.14 kJ/mol in the aqueous phase. A molecular docking study was performed to investigate the inhibitory activity of dexamethasone against the COVID-19 target protein (PDB ID: 6LU7). The dexamethasone showed potential therapeutic activity as a SARS CoV-2 main protease inhibitor due to its strong binding to the active sites of the protein target, with predicted free energy of binding values of −29.97 and −32.19 kJ/mol as calculated from AutoDock4 and AutoDock Vina, respectively. This study was intended to explore the potential use of the Dex@β-CD complex in drug delivery to enhance dexamethasone dissolution, thus improving its bioavailability and reducing its side effects.