Preparation, characterization and biological evaluation of β-cyclodextrin-biotin conjugate based podophyllotoxin complex

Renewable and Switchable Biofunctional Modification of Poly(dimethylsiloxane) Surfaces via Host-Guest Interactions for Enhanced Capture of Circulating Tumor Cells in Microfluidics

Circulating tumor cells (CTCs) are crucial for understanding cancer metastasis. Poly(dimethylsiloxane) (PDMS) microfluidic chips utilizing aptamers (APTs) effectively separate CTCs, but the hydrophobicity of PDMS causes issues with nonspecific adsorption and reduces cell viability. Therefore, it is imperative to develop innovative surface modification techniques for PDMS to enhance its biocompatibility and optimize its performance in microfluidic applications. In this study, oligo(ethylene glycol) methacrylate (OEGMA) and adamantane-modified OEGMA were copolymerized onto an initiator-containing PDMS surface. Poly(OEGMA) prevents nonspecific adsorption, and biotin-modified β-cyclodextrin (β-CD) was introduced through host-guest interaction between β-CD and adamantane. By using the biotin-streptavidin interaction, streptavidin and biotin-modified aptamers (TD05 APT and Sgc8 APT) were sequentially immobilized on the copolymer-grafted PDMS substrate. The data indicate that the PDMS substrate functionalized with TD05 APT achieved a capture efficiency of 91% and a selectivity of 30.2 for Ramos cells, while the substrate functionalized with Sgc8 APT achieved a capture efficiency of 93% and a selectivity of 33.3 for CEM cells. Furthermore, treating the APT-functionalized surfaces with sodium dodecyl sulfate released the β-CD component, allowing for the regeneration and switching of the surface biofunctionality by reimmobilizing TD05 APT or Sgc8 APT. Finally, the PDMS microfluidic chips modified using this strategy achieved high capture efficiency (96% for Ramos cells, 93% for CEM cells) and high selectivity (11.4 for Ramos cells, 9.2 for CEM cells). The host-guest chemistry endows the modified PDMS substrate with renewable and switchable biofunctionality, offering insights into the potential applications in the isolation and enrichment of CTCs.

From Natural Product Derivative to Hexagonal Prism Supermolecule: Potent Biofilm Disintegration, Enhanced Foliar Affinity, and Effective Management of Tomato Bacterial Canker

Clavibacter michiganensis (Cmm), designated as an A2 quarantine pest by the European and Mediterranean Plant Protection Organization (EPPO), incites bacterial canker of tomato, which presently eludes rapid and effective control methodologies. Dense biofilms formed by Cmm shield internal bacteria from host immune defenses and obstruct the ingress of agrochemicals. Even when agrochemicals disintegrate biofilms, splashing and bouncing during application disperse active ingredients away from target sites. Herein, we present a supramolecular strategy to fabricate a hexagonal prism-shaped material, BPGA@CB[8], assembled from an 18β-glycyrrhetinic acid derivative (PBGA) and host molecule-cucurbit[8]uril (CB[8]) via host-guest recognition. This positively charged material manifests multifaceted functionalities, notably the ability to surmount biofilm barriers, annihilate the encased pathogenic bacteria, and enhance foliar affinity of droplets. The strong in vitro potency and effective deposition of BPGA@CB[8] foster optimal conditions for robust in vivo efficacy, demonstrating superior protective and curative activities (56.9 %/53.4 %) against canker of tomato at a low-dose of 100 μg⋅mL-1 compared to BPGA (44.6 %/42.2 %), kasugamycin (30.1 %/28.4 %), and thiodiazole copper (35.4 %/31.0 %). This supramolecular material, based on natural product derivatives, provides a potent treatment for high-risk canker of tomato, and exemplifies the utility of supramolecular strategies in optimizing the attributes of natural products for managing plant bacterial diseases.

Approaches for Inclusion Complexes of Ezetimibe with Cyclodextrins: Strategies for Solubility Enhancement and Interaction Analysis via Molecular Docking

This study aimed to improve the solubility of ezetimibe (EZT), which has low aqueous solubility, by preparing complexes using β-cyclodextrin (β-CD) derivatives. Phase solubility studies and Job's plot confirmed a high apparent stability constant for EZT with β-CD and even higher constants with its derivatives, establishing a 1:1 stoichiometric ratio. The composites were prepared using spray drying over a range of molar ratios, and their physicochemical properties were evaluated using techniques such as scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FT-IR). Saturation solubility and in vitro dissolution tests revealed that solubility increased with higher CD molar ratios. EZT/RM-β-CD inclusion complexes (ICs) and EZT/DM-β-CD ICs exhibited a similar solubility, which was greater than that of EZT/HP-β-CD ICs and EZT/SBE-β-CD ICs (where RM, DM, HP, and SEB represent H, CH3, -CH2-CHOH-CH3 and -(CH2)4-SO3Na synthetic derivatives, respectively). Most complexes, except for EZT/SBE-β-CD at 1:2 or higher ratios, showed superior solubility compared with EZT powder and commercial products. Molecular docking simulations confirmed EZT inclusion within the CD, revealing hydrogen bonds and binding energies that aligned with solubility trends. These findings suggest that EZT complexes with β-CD derivatives significantly improve solubility, highlighting their potential for developing more effective oral solid formulations for hyperlipidemia treatment.

The effects of ligand distribution and density on the targeting properties of dual-targeting folate/biotin Pluronic F127/Poly (lactic acid) polymersomes

Targeted drug delivery systems modified with two or more ligands were expected to have better anti-tumor ability than those with just one ligand due to the complexity and heterogeneity of tumors. Thus, dual-targeting Pluronic/poly (lactic acid) polymersomes containing biotin (BT) and folic acid (FA) ligands (BT/FA-F127-PLA) were designed to study their targeting properties over human ovarian cancer cells (OVCAR-3). Two kinds of dual-ligand targeting polymersomes, BT/FA-F127-PLA and (BT + FA)-F127-PLA, were prepared to study the effect of the dual-ligand distribution on the cell targeting of polymersomes. BT/FA-F127-PLA had two ligands distributed in the same polymersomes whereas (BT + FA)-F127-PLA had two ligands distributed in different polymersomes. The in vitro cytotoxicity and cellular uptake, and in vivo pharmacokinetic behaviors of BT/FA-F127-PLA were superior to those of (BT + FA)-F127-PLA. It suggested that biotin and folate ligands distributed on the same polymersomes could have the targeting effect of synergistic promotion. Further experiments on cell uptake mechanisms of polymersomes showed that the uptake of targeted polymersomes was associated with energy-dependent endocytosis, involving clathrin, caveolin protein, macropinocytosis and ligand receptor-mediated endocytosis. In addition, the effect of different density ratios of dual ligands for BT/FA-F127-PLA was further studied. The results showed that the cellular targeting effect of BT/FA-F127-PLA was the strongest when the molar ratio of biotin to folic acid was 7.5 %: 7.5 %. In conclusion, BT/FA-F127-PLA dual-targeting polymersomes could be good candidates as targeted drug delivery carriers.

Cyclodextrin Dimers Functionalized with Biotin as Nanocapsules for Active Doxorubicin Delivery Against MCF-7 Breast Cell Line

Cyclodextrin dimers have been investigated as potential nanocapsules of biomolecules. The presence of two cavities can improve the stability of inclusion complexes, working as a hydrophilic sandwich of poorly water-soluble species. Here, we designed new β- and γ-cyclodextrin dimers functionalized with biotin as a targeting unit and tested the new bioconjugates as doxorubicin delivery systems in cancer cells. Biotin can recognize the Sodium-dependent Multivitamin Transporter (SMVT) receptor, encoded by the Solute Carrier Family 5 Member 6 (SLC5A6) gene and improve the uptake of drugs. We evaluated the expression of the SLC5A6 transcript in human cell lines to select the best cell model (MCF-7) for the in vitro studies. Furthermore, in the cell lines, we investigated the transcript levels of genes correlated to biotin cell availability, Holocarboxylase Synthetase (or HCS encoded by HLCS gene) and Biotinidase (encoded by BTD gene) enzymes. Moreover, the expression of ATP Binding Cassette Subfamily G Member 2 transporter (encoded by ABCG2 gene), which may play a role in doxorubicin resistance, has been investigated. The antiproliferative activity of the doxorubicin complexes with the dimers has been determined to study the effect of the biotin moiety on the cytotoxicity in MCF-7 cancer cells.

Curcumin-based residue-free and reusable photodynamic inactivation system for liquid foods and its application in freshly squeezed orange juice

To enhance curcumin's application in photodynamic inactivation (PDI) of liquid foods, a supramolecular complex of biotin-modified β-cyclodextrin and curcumin (Biotin-CD@Cur) was synthesized. This complex significantly improves curcumin's solubility, stability, and PDI efficiency. Following PDI, Biotin-CD@Cur can be magnetically separated from the liquid matrix using streptavidin-coated magnetic beads (SA-MBs). Leveraging the reversible binding between streptavidin and biotin, Biotin-CD@Cur and SA-MBs fully dissociate in ultrapure water at 70 °C, enabling reuse. Antibacterial tests in freshly squeezed orange juice demonstrated that a low dose of 1.5 J/cm2 from a 420 nm LED array and 10 μg/mL of Biotin-CD@Cur achieved log reductions of 3.287 ± 0.015 for Staphylococcus aureus and 2.961 ± 0.011 for Listeria monocytogenes, while preserving the juice's flavor and nutritional contents. The PDI system remained effective for at least four cycles. Ultra-performance liquid chromatography and atomic absorption spectroscopy confirmed no residues of system components in the juice after magnetic separation.

Synthesis and bioevaluation of water-soluble β-cyclodextrin-diterpene acid conjugates

A series of β-cyclodextrin (β-CD)-conjugates were prepared by combining three abietane-type diterpene acids with two azide-functionalized β-CDs via click chemistry, and the antiviral activity against wild-type and omicron SARS-CoV-2 spike pseudovirus as well as the antibacterial activity against Escherichia coli were investigated. All the synthesised conjugates exhibited no significant cytotoxicity to BHK-21-hACE2 cells with cell viability over 80% at concentration of 15 µM. Among the conjugates, the heptavalent β-CD-dehydroabietic acid conjugate 6b exhibited higher anti-SARS-CoV-2 activity against the omicron variant compared to the other conjugates. This study suggested that the multivalent diterpene acid derivatives may have potential application against coronaviruses as entry inhibitors.

Enhancement of the solubility and oral bioavailability of altrenogest through complexation with hydroxypropyl-β-cyclodextrin

Altrenogest (ALT), a synthetic progestogen, serves a critical role in estrus synchronization among animals like gilts and mares. However, its practical application in animal husbandry is hampered due to its poor solubility and limited oral bioavailability. To address this challenge, a solvent evaporation method was employed to create an inclusion complex of ALT with hydroxypropyl-β-cyclodextrin (ALT/HP-β-CD). The formation of this inclusion complex was confirmed by scanning electron microscopy, power X-ray diffraction, differential scanning calorimetry, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and docking calculations. In addition, we further conducted pharmacokinetic investigation involving gilts, comparing ALT/HP-β-CD inclusion complex to an ALT oral solution. The physicochemical characterization results unveiled a transformation of ALT's crystal morphology into an amorphous state, with ALT effectively entering the cavity of HP-β-CD. Compared with ALT, the solubility of ALT/HP-β-CD inclusion complex increased by 1026.51-fold, and its dissolution rate demonstrated significant improvement. Pharmacokinetic assessments further revealed that the oral bioavailability of ALT/HP-β-CD inclusion complex surpassed that of the ALT oral solution, with a relative bioavailability of 114.08 %. In conclusion, complexation with HP-β-CD represents a highly effective approach to improve both the solubility and oral bioavailability of ALT.

Chemistry and Biology of Podophyllotoxins: An Update

Podophyllotoxin is an aryltetralin lignan lactone derived from different plants of Podophyllum. It consists of five rings with four chiral centers, one trans-lactone and one aryl tetrahydronaphthalene skeleton with multiple modification sites. Moreover, podophyllotoxin and its derivatives showed lots of bioactivities, including anticancer, anti-inflammatory, antiviral, and insecticidal properties. The demand for podophyllotoxin and its derivatives is rising as a result of their high efficacy. As a continuation of our previous review (Chem. Eur. J., 2017, 23, 4467-4526), herein, total synthesis, biotransformation, structural modifications, bioactivities, and structure-activity relationships of podophyllotoxin and its derivatives from 2017 to 2022 are summarized. Meanwhile, a piece of update information on the origin of new podophyllotoxin analogues from plants from 2014 to 2022 was compiled. We hope that this review will provide a reference for future high value-added applications of podophyllotoxin and its analogues in the pharmaceutical and agricultural fields.

Plug-and-Play Biointerfaces: Harnessing Host-Guest Interactions for Fabrication of Functional Polymeric Coatings

Polymeric surface coatings capable of effectively integrating desired functional molecules and ligands are attractive for fabricating bio-interfaces necessary for various applications. Herein, we report the design of a polymeric platform amenable to such modifications in a modular fashion through host-guest chemistry. Copolymers containing adamantane (Ada) moieties, diethylene glycol (DEG) units, and silyloxy groups to provide functionalization handles, anti-biofouling character, and surface attachment, respectively, were synthesized. These copolymers were employed to modify silicon/glass surfaces to enable their functionalization using beta-cyclodextrin (βCD) containing functional molecules and bioactive ligands. Moreover, surface functionalization could be spatially controlled using a well-established technique like microcontact printing. Efficient and robust functionalization of polymer-coated surfaces was demonstrated by immobilizing a βCD-conjugated fluorescent rhodamine dye through the specific noncovalent binding between Ada and βCD units. Furthermore, biotin, mannose, and cell adhesive peptide-modified βCD were immobilized onto the Ada-containing polymer-coated surfaces to direct noncovalent conjugation of streptavidin, concanavalin A (ConA), and fibroblast cells, respectively. It was demonstrated that the mannose-functionalized coating could selectively bind to the target lectin ConA, and the interface could be regenerated and reused several times. Moreover, the polymeric coating was adaptable for cell attachment and proliferation upon noncovalent modification with cell-adhesive peptides. One can envision that the facile synthesis of the Ada-based copolymers, mild conditions for coating surfaces, and their effective transformation to various functional interfaces in a modular fashion offers an attractive approach to engineering functional interfaces for several biomedical applications.

Evaluation on the inclusion behavior of β-cyclodextrins with lycorine and its hydrochloride

Lycorine (Lyc) and its hydrochloride (Lyc∙HCl) as effective drugs can fight against many diseases including novel coronavirus (COVID-19) based on their antiviral and antitumor mechanism. Beta-cyclodextrin (β-CD) is considered a promising carrier in improving its efficacy while minimizing cytotoxicity due to the good spatial compatibility with Lyc. However, the detailed mechanism of inclusion interaction still remains to be further evaluated. In this paper, six inclusion complexes based on β-CDs, Lyc and Lyc∙HCl were processed through ultrasound in the mixed solvent of ethanol and water, and their inclusion behavior was characterized after lyophilization. It was found that the inclusion complexes based on sulfobutyl-beta-cyclodextrin (SBE-β-CD) and Lyc∙HCl had the best encapsulation effect among prepared inclusion complexes, which may be attributed to the electrostatic interaction between sulfonic group of SBE-β-CD and quaternary amino group of Lyc∙HCl. Moreover, the complexes based on SBE-β-CD displayed pH-sensitive drug release property, good solubilization, stability and blood compatibility, indicating their potential as suitable drug carriers for Lyc and Lyc∙HCl.

Enhanced oral bioavailability of koumine by complexation with hydroxypropyl-β-cyclodextrin: preparation, optimization, ex vivo and in vivo characterization

Koumine (KME) is an active alkaloid extracted from Gelsemium elegans, and its diverse bioactivities have been studied for decades. However, KME exhibits poor solubility and low oral bioavailability, which hampers its potential therapeutic exploitation. This work aimed to develop optimized inclusion complexes to improve the bioavailability of KME. The KME/hydroxypropyl-β-cyclodextrin (KME/HP-β-CD) inclusion complexes were prepared by the solvent evaporation method and later optimized using the Box-Behnken design. The optimal KME/HP-β-CD was characterized by scanning electron microscopy, Fourier transforms infrared spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance spectroscopy. The physicochemical characterization results revealed that the crystalline state of KME was transformed into an amorphous form, forming KME/HP-β-CD inclusion complexes. Compared with KME, the solubility and in vitro release rate of KME/HP-β-CD was significantly enhanced by 52.34- and 1.3-fold, respectively. Further research was performed to investigate the intestinal absorption characteristics and in vivo bioavailability in rats. The optimal KME/HP-β-CD showed enhanced absorptive permeability and relative bioavailability increased more than two-fold compared to that of raw KME. These results indicate that the optimal KME/HP-β-CD can be used as an effective drug carrier to improve the solubility, intestinal absorption, and bioavailability of KME.