Adamantoid Scaffolds for Multiple Cargo Loading and Cellular Delivery as β-Cyclodextrin Inclusion Complexes

Fluorescence enhancement of cyanine/hemicyanine dyes with adamantane as an auxochrome through host-guest inclusion with methylated cyclodextrin in water

Fluorescence of cyanine dyes is often quenched in aqueous solution, limiting their application in water or biological system. In this work, a novel strategy of host-guest interaction based on cyanine derivatives containing auxochromes was proposed to enhance fluorescence in aqueous solution and cell imaging. By using the host (methylated β-cyclodextrin, M-β-CD) to inclusion and suppress the TICT effect of the dye, the fluorescence was significantly enhanced at lower host concentration. Cyanine and hemicyanine dyes (Ad-NH-1a, Ad-NH-1b and Ad-NH-2) with adamantyl group as auxochrome were designed and prepared by using host-guest complexation to inhibit the TICT effect of dyes, thus realizing the purpose of significantly enhancing the fluorescence of dyes at lower concentration. After adding M-β-CD, the fluorescence quantum yields of these dyes increased to 15.9 %, 21.8 %, and 6.08 %, respectively. In comparison, the fluorescence quantum yield of the dyes Ad-CONH-1 and Ad-CONH-2 containing adamantyl groups, increased only modestly from 1.78 to 2.83 times. Encouraged by these satisfactory results, further cell experiments were conducted with Ad-NH-1a, Ad-NH-1b, and Ad-NH-2. The experiment showed that adding a lower concentration of M-β-CD significantly reduced the clear imaging dosage of the probe (0.3 μM) without altering the organelle targeting of the probes.

From dansyl-modified biofilm disruptors to β-cyclodextrin-optimized multifunctional supramolecular nanovesicles: their improved treatment for plant bacterial diseases

BACKGROUND

Bacterial diseases caused by phytopathogenic Xanthomonas pose a significant threat to global agricultural production, causing substantial economic losses. Biofilm formation by these bacteria enhances their resistance to environmental stressors and chemical treatments, complicating disease control. The key to overcoming this challenge lies in the development of multifunctional green bactericides capable of effectively breaking down biofilm barriers, improving foliar deposition properties, and achieving the control of bacterial diseases.

RESULTS

We have developed a kind of innovative green bactericide from small-molecule conception to eco-friendly supramolecular nanovesicles (DaPA8@β -CD) by host-guest supramolecular technology. These nanoscale assemblies demonstrated the ability to inhibit and eradicate biofilm formation, while also promoted foliar wetting and effective deposition properties, laying the foundation for improving agrochemical utilization. Studies revealed that DaPA8@β -CD exhibited significant biofilm inhibition (78.66% at 7.0 µ g mL- 1) and eradication (83.50% at 25.0 µ g mL- 1), outperforming DaPA8 alone (inhibition: 59.71%, eradication: 66.79%). These nanovesicles also reduced exopolysaccharide formation and bacterial virulence. In vivo experiments showed enhanced control efficiency against citrus bacterial canker (protective: 78.04%, curative: 50.80%) at a low dose of 200 µ g mL- 1, superior to thiodiazole-copper-20%SC and DaPA8 itself.

CONCLUSION

This study demonstrates the potential of DaPA8@β -CD nanovesicles as multifunctional bactericides for managing Xanthomonas -induced plant diseases, highlighting the advantages of using host-guest supramolecular technology to enhance agrochemical bioavailability.

β-cyclodextrin/spiropyran-functionalized optical-driven hydrogel film for bisphenol A detection in food packaging

Bisphenol A (BPA), an endocrine disruptor, is widely used in food packaging materials, including drink containers. Sensitive detection of BPA is crucial to food safety. Herein, we have developed a novel optical-driven hydrogel film sensor for sensitive BPA detection based on the displacement of spiropyran (SP) from β-cyclodextrin (β-CD) cavity by BPA followed by the photochromism of the released SP. The released SP converts to the ring-opened merocyanine form which shows an enhanced red fluorescence in the dark. The sensor demonstrates a linear detection range from 0.1 to 20 μg mL-1 with a limit of detection at 0.027 μg mL-1 and a limit of quantification at 0.089 μg mL-1. Notably, the proposed β-CD/SP hydrogel can be reused due to the reversible isomerization of SP and the reversible host-guest interaction. This sensor also shows good performance for BPA determination in real samples, indicating its great potential for food safety monitoring.

An Artificial Light-Harvesting System based on Supramolecular AIEgen Assembly

Photosynthesis is a complex multi-step process in which light collection is the initial step of photosynthesis and plays an important role in the utilization of solar energy. In order to improve the utilization of sunlight, researchers have developed a variety of artificial light-harvesting systems to simulate photosynthesis in nature. Here, we report a supramolecular artificial light-harvesting system in aqueous solution. Since β-cyclodextrin (β-CD) has a hydrophobic cavity and a hydrophilic outer surface, we adopt β-cyclodextrin (β-CD) as the host molecule and use adamantane as the guest molecule. At the same time, we modified β-CD with the donor molecule naphthalimide and adamantane with the tetraphenylethylene molecule which has aggregation-induced emission (AIE) effects. By using fluorescent molecules with AIE, the self-quenching effect caused by aggregation in aqueous solution can be effectively avoided. Due to the host-guest interaction of β-CD and adamantane, nanoparticles with stable structure and uniform size can be spontaneously assembled in water. Because of the close distance and strong spectral overlap between naphthalimide and tetraphenylethylene, Förster resonance energy transfer (FRET) was realized, and artificial light-harvesting system was successfully constructed in aqueous solution. Therefore, this study provides a new strategy for constructing artificial light-harvesting system, and the artificial light-harvesting system shows broad application prospects in aqueous solutions.

Formulation of Ensulizole with Beta-Cyclodextrins for Improved Sunscreen Activity and Biocompatibility

In today's context, prolonged exposure to sunlight is widely recognized as a threat to human health, leading to a range of adverse consequences, including skin cancers, premature skin aging, and erythema. To mitigate these risks, preventive actions mainly focus on advocating the application of sunscreen lotions and minimizing direct exposure to sunlight. This research study specifically centered on ensulizole (ENS), a prominent ingredient in sunscreens. The objective was to create inclusion complexes (ICs) with Beta-cyclodextrin (B-CD) and its hydroxypropyl derivatives (H-CD). Using phase solubility measurements, we determined that both B-CD and H-CD form 1:1 stoichiometric ICs with ENS. Proton nuclear magnetic resonance spectral (1H NMR) analysis confirmed that the phenyl portion of ENS is encapsulated within the B-CD cavity. Significant changes in surface morphology were observed during the formation of these ICs compared to ENS and CDs alone. Quantum mechanical calculations were employed to further support the formation of ICs by providing energy data. Particularly, the photostability of the ENS:B-CD ICs remained intact for up to four hours of UV exposure, with no significant alterations in the structure of ENS. Furthermore, comprehensive biocompatibility assessments yielded encouraging results, suggesting the potential application of these inclusion complexes in cosmetics as a UVB sunscreen. In summary, our research underscores the successful creation of inclusion complexes characterized by enhanced photostability and safe biocompatibility.

Cyclodextrin Inclusion Complexes for Improved Drug Bioavailability and Activity: Synthetic and Analytical Aspects

Many active pharmaceutical ingredients show low oral bioavailability due to factors such as poor solubility and physical and chemical instability. The formation of inclusion complexes with cyclodextrins, as well as cyclodextrin-based polymers, nanosponges, and nanofibers, is a valuable tool to improve the oral bioavailability of many drugs. The microencapsulation process modifies key properties of the included drugs including volatility, dissolution rate, bioavailability, and bioactivity. In this context, we present relevant examples of the stabilization of labile drugs through the encapsulation in cyclodextrins. The formation of inclusion complexes with drugs belonging to class IV in the biopharmaceutical classification system as an effective solution to increase their bioavailability is also discussed. The stabilization and improvement in nutraceuticals used as food supplements, which often have low intestinal absorption due to their poor solubility, is also considered. Cyclodextrin-based nanofibers, which are polymer-free and can be generated using environmentally friendly technologies, lead to dramatic bioavailability enhancements. The synthesis of chemically modified cyclodextrins, polymers, and nanosponges based on cyclodextrins is discussed. Analytical techniques that allow the characterization and verification of the formation of true inclusion complexes are also considered, taking into account the differences in the procedures for the formation of inclusion complexes in solution and in the solid state.