Amphiphilic cyclodextrin nanoparticles

Cyclodextrin microneedles for the delivery of a nanoparticle-based peptide antigen vaccine

In recent years, microneedles (MNs) have gained considerable interest in drug formulation due to their non-invasive and patient-friendly nature. Dissolving MNs have emerged as a promising approach to enhance drug delivery across the skin in a painless manner without generating sharp waste and providing the possibility for self-administration. Cyclodextrins, a group of cyclic oligosaccharides, are well-established in pharmaceutical products due to their safety and unique ability to form inclusion complexes with various drug molecules. In this manuscript, we report the development and characterization of dissolving MNs composed of cyclodextrins for intradermal delivery of a cyclodextrin-based nanoparticulate vaccine. Different cyclodextrins were tested and the most promising candidates were fabricated into MNs by micromolding. The MNs' piercing effectiveness and drug permeation across the skin were tested ex vivo. Furthermore, in vivo studies were carried out to assess the skin's tolerance to cyclodextrin-based MNs, and to evaluate the immune response using a model peptide antigen in a mouse model. The data revealed that the MNs were well-tolerated and effective, even leading to dose-sparing effects. This study highlights the potential of cyclodextrin-based dissolving MNs as a versatile platform for intradermal vaccine delivery, providing a compatible matrix for nanoparticulate formulations to enhance immune responses.

Enhancing Systemic Translocation of Insecticides via Nanoformulations Incorporating β-Cyclodextrin Octadecarboxylate as a Carrier

The conversion of contact-killing pesticides into systemic pesticides can significantly enhance the bioavailability of pesticides, thereby reducing pesticide usage and environmental harm. A series of β-cyclodextrin fatty acid esters with varying branch chains were synthesized and employed as carriers in nanoformulation of insecticide. The investigation revealed that nanoformulations prepared using β-cyclodextrin octadecarboxylate (β-CDs) exhibited superior stability and remarkable systemic translocation within plants. Six contact-killing insecticide nanoformulations were developed utilizing β-CDs as carriers, and tests indicated that β-CDs significantly enhanced the systemic translocation of insecticides in plants compared to carrier-free nanoformulations. It was found that β-CDs increased the level of systemic translocation of insecticides by 5-12 times. Additionally, characterization results from λ-cyhalothrin-β-CDs nanoformulation demonstrated their superior ability to improve photolysis resistance, prolong release time, and extend insecticidal duration. Consequently, β-CDs can be utilized as a green additive in pesticide production to enhance the systemic translocation of pesticides in plants and increase their bioavailability.

Engineered Self-Assembly of Amphiphilic Cyclodextrin Conjugates for Drug Encapsulation

Cyclodextrins are a group of naturally occurring oligosaccharides that have widely been studied and applied in pharmaceutical formulations forming inclusion complexes with a broad variety of drugs exhibiting different hydrophilicity as well as molecular weights. Grafting aliphatic chains onto native cyclodextrins renders them amphiphilic and enables self-assembly into supramolecular structures that have already been explored for drug delivery. Based on the possibility of controlling the inherent physicochemical properties by modifying their chemical structure, amphiphilic cyclodextrin conjugates hold a great potential to become a drug delivery platform adaptable to the individual needs of specific active drug molecules. In this work, a library of amphiphilic cyclodextrin derivatives was synthesized by conjugating aliphatic chains of different lengths to native β-cyclodextrin via thioether or ester bonds. Upon nanoprecipitation, the synthesized amphiphilic cyclodextrin derivatives spontaneously self-assembled into nanosized supramolecular structures with a monodisperse size distribution. We systematically investigated the relationship between the molecular structure of the amphiphilic cyclodextrin derivatives and the corresponding self-assembly into nanosystems as well as the encapsulation of model drugs with different physicochemical properties. Encapsulation efficiencies up to 97% and pH-dependent release profiles were achieved. We found that both the aliphatic chain length and the linker molecule determine the respective self-assembly and drug encapsulation mechanism of the individual system. The colloidal stability and biocompatibility with human cells of all derivatives were proven. Consequently, amphiphilic cyclodextrin conjugates provide a drug delivery platform with tailor-made control over physicochemical properties and high drug encapsulation efficiency for a broad range of drug molecules, thus offering great potential for the development of future therapeutics with improved therapeutic efficiency.

Addressing the complexities in measuring cyclodextrin-sterol binding constants: A multidimensional study

A class of cyclodextrin (CD) dimers has emerged as a potential new treatment for atherosclerosis; they work by forming strong, soluble inclusion complexes with oxysterols, allowing the body to reduce and heal arterial plaques. However, characterizing the interactions between CD dimers and oxysterols presents formidable challenges due to low sterol solubility, the synthesis of modified CDs resulting in varying number and position of molecular substitutions, and the diversity of interaction mechanisms. To address these challenges and illuminate the nuances of CD-sterol interactions, we have used multiple orthogonal approaches for a comprehensive characterization. Results obtained from three independent techniques - metadynamics simulations, competitive isothermal titration calorimetry, and circular dichroism - to quantify CD-sterol binding are presented. The objective of this study is to obtain the binding constants and gain insights into the intricate nature of the system, while accounting for the advantages and limitations of each method. Notably, our findings demonstrate ∼1000× stronger affinity of the CD dimer for 7-ketocholesterol in comparison to cholesterol for the 1:1 complex in direct binding assays. These methodologies and findings not only enhance our understanding of CD dimer-sterol interactions, but could also be generally applicable to prediction and quantification of other challenging host-guest complex systems.

CD-MOFs: From preparation to drug delivery and therapeutic application

Cyclodextrin metal-organic frameworks (CD-MOFs) show considerable advantages of edibility, degradability, low toxicity, and high drug loading, which have attracted enormous interest, especially in drug delivery. This review summarizes the typical synthesis approaches of CD-MOFs, the drug loading methods, and the mechanism of encapsulation and release. The influence of the structure of CD-MOFs on their drug encapsulation and release is highlighted. Finally, the challenges CD-MOFs face are discussed regarding biosafety assessment systems, stability in aqueous solution, and metal ion effect.

Self-Assembly Nanochaperone with Tunable Hydrophilic-Hydrophobic Surface for Controlled Protein Refolding

Nanochaperones (nChaps) have significant potential to inhibit protein aggregation and assist in protein refolding. The interaction between nChaps and proteins plays an important role in nChaps performing chaperone-like functions, but the interaction mechanism remains elusive. In this work, a series of nChaps with tunable hydrophilic-hydrophobic surfaces are prepared, and the process of nChaps-assisted denatured protein refolding is systematically explored. It is found that an appropriate hydrophilic-hydrophobic balance on the nChap surface is critical for enhancing protein renaturation. This is because only the optimal interaction between nChap and protein can simultaneously guarantee the suitable capture and sufficient release of client proteins. The findings in this work will provide an effective reference for the design of nChaps and contribute to the development of the potential of nChaps in the future.

Cyclodextrin: A prospective nanocarrier for the delivery of antibacterial agents against bacteria that are resistant to antibiotics

Supramolecular chemistry introduces us to the macrocyclic host cyclodextrin, which has a hydrophobic cavity. The hydrophobic cavity has a higher affinity for hydrophobic guest molecules and forms host-guest complexation with non-covalent interaction. Three significant cyclodextrin kinds are α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. The most often utilized is β-cyclodextrin (β-CD). An effective weapon against bacteria that are resistant to antibiotics is cyclodextrin. Several different kinds of cyclodextrin nanocarriers (β-CD, HP-β-CD, Meth-β-CD, cationic CD, sugar-grafted CD) are utilized to enhance the solubility, stability, dissolution, absorption, bioavailability, and permeability of the antibiotics. Cyclodextrin also improves the effectiveness of antibiotics, antimicrobial peptides, metallic nanoparticles, and photodynamic therapy (PDT). Again, cyclodextrin nanocarriers offer slow-release properties for sustained-release formulations where steady-state plasma antibiotic concentration is needed for an extended time. A novel strategy to combat bacterial resistance is a stimulus (pH, ROS)-responsive antibiotics released from cyclodextrin carrier. Once again, cyclodextrin traps autoinducer (AI), a crucial part of bacterial quorum sensing, and reduces virulence factors, including biofilm formation. Cyclodextrin helps to minimize MIC in particular bacterial strains, keep antibiotic concentrations above MIC in the infection site and minimize the possibility of antibiotic and biofilm resistance. Sessile bacteria trapped in biofilms are more resistant to antibiotic therapy than bacteria in a planktonic form. Cyclodextrin also involves delivering antibiotics to biofilm and resistant bacteria to combat bacterial resistance.

Supramolecular nanomedicines based on host-guest interactions of cyclodextrins

In the biomedical and pharmaceutical fields, cyclodextrin (CD) is undoubtedly one of the most frequently used macrocyclic compounds as the host molecule because it has good biocompatibility and can increase the solubility, bioavailability, and stability of hydrophobic drug guests. In this review, we generalized the unique properties of CDs, CD-related supramolecular nanocarriers, supramolecular controlled release systems, and targeting systems based on CDs, and introduced the paradigms of these nanomedicines. In addition, we also discussed the prospects and challenges of CD-based supramolecular nanomedicines to facilitate the development and clinical translation of these nanomedicines.

A Systematic Review of Clinical Trials on the Efficacy and Safety of CRLX101 Cyclodextrin-Based Nanomedicine for Cancer Treatment

CRLX101 is a cyclodextrin-based nanopharmaceutical designed to improve the delivery and efficacy of the anti-cancer drug camptothecin. Cyclodextrins have unique properties that can enhance drug solubility, stability, and bioavailability, making them an attractive option for drug delivery. The use of cyclodextrin-based nanoparticles can potentially reduce toxicity and increase the therapeutic index compared to conventional chemotherapy. CRLX101 has shown promise in preclinical studies, demonstrating enhanced tumor targeting and prolonged drug release. This systematic review followed PRISMA guidelines, assessing the efficacy and toxicity of CRLX101 in cancer treatment using clinical trials. Studies from January 2010 to April 2023 were searched in PubMed, Scopus, Web of Science, and Cochrane Database of Systematic Reviews, using specific search terms. The risk of bias was assessed using ROBINS-I and Cochrane risk-of-bias tools. After screening 6018 articles, 9 were included in the final review. These studies, conducted between 2013 and 2022, focused on patients with advanced or metastatic cancer resistant to standard therapies. CRLX101 was often combined with other therapeutic agents, resulting in improvements such as increased progression-free survival and clinical benefit rates. Toxicity was generally manageable, with common adverse events including fatigue, nausea, and anemia.

Oxygen-releasing biomaterials for chronic wounds breathing: From theoretical mechanism to application prospect

Chronic wounds have always been considered as "gordian knots" in medicine, in which hypoxia plays a key role in blocking healing. To address this challenge, although tissue reoxygenation therapy based on hyperbaric oxygen therapy (HBOT) has been performed clinically for several years, the bench to bedside still urges the evolution of oxygen-loading and -releasing strategies with explicit benefits and consistent outcome. The combination of various oxygen carriers with biomaterials has gained momentum as an emerging therapeutic strategy in this field, exhibiting considerable application potential. This review gives an overview of the essential relationship between hypoxia and delayed wound healing. Further, detailed characteristics, preparation methods and applications of various oxygen-releasing biomaterials (ORBMs) will be elaborated, including hemoglobin, perfluorocarbon, peroxide, and oxygen-generating microorganisms, those biomaterials are applied to load, release or generate a vast of oxygen to relieve the hypoxemia and bring the subsequent cascade effect. The pioneering papers regarding to the ORBMs practice are presented and trends toward hybrid and more precise manipulation are summarized.

The Role of Cyclodextrin in the Construction of Nanoplatforms: From Structure, Function and Application Perspectives

Cyclodextrins (CyDs) in nano drug delivery systems have received much attention in pursuit of good compatibility, negligible toxicity, and improved pharmacokinetics of drugs. Their unique internal cavity has widened the application of CyDs in drug delivery based on its advantages. Besides this, the polyhydroxy structure has further extended the functions of CyDs by inter- and intramolecular interactions and chemical modification. Furthermore, the versatile functions of the complex contribute to alteration of the physicochemical characteristics of the drugs, significant therapeutic promise, a stimulus-responsive switch, a self-assembly capability, and fiber formation. This review attempts to list recent interesting strategies regarding CyDs and discusses their roles in nanoplatforms, and may act as a guideline for developing novel nanoplatforms. Future perspectives on the construction of CyD-based nanoplatforms are also discussed at the end of this review, which may provide possible direction for the construction of more rational and cost-effective delivery vehicles.

Amphiphilic Cyclodextrin Nanoparticles as Delivery System for Idebenone: A Preformulation Study

Idebenone (IDE), a synthetic short-chain analogue of coenzyme Q10, is a potent antioxidant able to prevent lipid peroxidation and stimulate nerve growth factor. Due to these properties, IDE could potentially be active towards cerebral disorders, but its poor water solubility limits its clinical application. Octanoyl-β-cyclodextrin is an amphiphilic cyclodextrin (ACyD8) bearing, on average, ten octanoyl substituents able to self-assemble in aqueous solutions, forming various typologies of supramolecular nanoassemblies. Here, we developed nanoparticles based on ACyD8 (ACyD8-NPs) for the potential intranasal administration of IDE to treat neurological disorders, such as Alzheimer’s Disease. Nanoparticles were prepared using the nanoprecipitation method and were characterized for their size, zeta potential and morphology. STEM images showed spherical particles, with smooth surfaces and sizes of about 100 nm, suitable for the proposed therapeutical aim. The ACyD8-NPs effectively loaded IDE, showing a high encapsulation efficiency and drug loading percentage. To evaluate the host/guest interaction, UV-vis titration, mono- and two-dimensional NMR analyses, and molecular modeling studies were performed. IDE showed a high affinity for the ACyD8 cavity, forming a 1:1 inclusion complex with a high association constant. A biphasic and sustained release of IDE was observed from the ACyD8-NPs, and, after a burst effect of about 40%, the release was prolonged over 10 days. In vitro studies confirmed the lack of toxicity of the IDE/ACyD8-NPs on neuronal SH-SY5Y cells, and they demonstrated their antioxidant effect upon H2O2 exposure, as a general source of ROS.

Micro and nanotechnologies: The little formulations that could

The first publication of micro- and nanotechnology in medicine was in 1798 with the use of the Cowpox virus by Edward Jenner as an attenuated vaccine against Smallpox. Since then, there has been an explosion of micro- and nanotechnologies for medical applications. The breadth of these micro- and nanotechnologies is discussed in this piece, presenting the date of their first report and their latest progression (e.g., clinical trials, FDA approval). This includes successes such as the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines from Pfizer, Moderna, and Janssen (Johnson & Johnson) as well as the most popular nanoparticle therapy, liposomal Doxil. However, the enormity of the success of these platforms has not been without challenges. For example, we discuss why the production of Doxil was halted for several years, and the bankruptcy of BIND therapeutics, which relied on a nanoparticle drug carrier. Overall, the field of micro- and nanotechnology has advanced beyond these challenges and continues advancing new and novel platforms that have transformed therapies, vaccines, and imaging. In this review, a wide range of biomedical micro- and nanotechnology is discussed to serve as a primer to the field and provide an accessible summary of clinically relevant micro- and nanotechnology platforms.

Mass Spectrometry of Esterified Cyclodextrins

Cyclodextrins are cyclic oligosaccharides that have received special attention due to their cavity-based structural architecture that imbues them with outstanding properties, primarily related to their capacity to host various guest molecules, from low-molecular-mass compounds to polymers. Cyclodextrin derivatization has been always accompanied by the development of characterization methods, able to unfold complicated structures with increasing precision. One of the important leaps forward is represented by mass spectrometry techniques with soft ionization, mainly matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI). In this context, esterified cyclodextrins (ECDs) benefited also from the formidable input of structural knowledge, thus allowing the understanding of the structural impact of reaction parameters on the obtained products, especially for the ring-opening oligomerization of cyclic esters. The current review envisages the common mass spectrometry approaches such as direct MALDI MS or ESI MS analysis, hyphenated liquid chromatography-mass spectrometry, and tandem mass spectrometry, employed for unraveling the structural features and particular processes associated with ECDs. Thus, the accurate description of complex architectures, advances in the gas phase fragmentation processes, assessment of secondary reactions, and reaction kinetics are discussed in addition to typical molecular mass measurements.

Progress of polymer-based strategies in fungal disease management: Designed for different roles

Fungal diseases have posed a great challenge to global health, but have fewer solutions compared to bacterial and viral infections. Development and application of new treatment modalities for fungi are limited by their inherent essential properties as eukaryotes. The microorganism identification and drug sensitivity analyze are limited by their proliferation rates. Moreover, there are currently no vaccines for prevention. Polymer science and related interdisciplinary technologies have revolutionized the field of fungal disease management. To date, numerous advanced polymer-based systems have been developed for management of fungal diseases, including prevention, diagnosis, treatment and monitoring. In this review, we provide an overview of current needs and advances in polymer-based strategies against fungal diseases. We high light various treatment modalities. Delivery systems of antifungal drugs, systems based on polymers' innate antifungal activities, and photodynamic therapies each follow their own mechanisms and unique design clues. We also discuss various prevention strategies including immunization and antifungal medical devices, and further describe point-of-care testing platforms as futuristic diagnostic and monitoring tools. The broad application of polymer-based strategies for both public and personal health management is prospected and integrated systems have become a promising direction. However, there is a gap between experimental studies and clinical translation. In future, well-designed in vivo trials should be conducted to reveal the underlying mechanisms and explore the efficacy as well as biosafety of polymer-based products.

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.

β-cyclodextrin based nano gene delivery using pharmaceutical applications to treat Wolfram syndrome

Wolfram syndrome is a rare multisystem autosomal recessive neurodegenerative disorder that affects the brain and central nervous system. Currently, there is no cure or treatment for Wolfram syndrome. Therefore, new techniques are needed to target the loss of the WFS1 gene. Gene therapy approach to introduce a functional gene using a viral or a non-viral vector could be a treatment strategy for Wolfram syndrome 1 (WS1). Viral vectors have therapeutic benefits and greater efficiency; however, they pose a high health risk. Recently pharmaceutical therapeutic research has developed cell-penetrating non-viral nano molecules that could be used as vectors for gene delivery. Among nonviral vectors, the unique properties of β-cyclodextrin suggest that it can be a promising safe vector for gene delivery.

Encapsulation of Essential Oils in Nanocarriers for Active Food Packaging

Active packaging improves a packaging system's effectiveness by actively integrating additional components into the packaging material or the headspace around the packaging. Consumer demand and awareness have grown enough to replace chemical agents with natural active agents. Essential oils (EOs) are extensively distributed throughout nature but at low levels and sometimes with poor recovery yields, which poses an issue with their application in food. Due to the instability of EOs when added directly into a food product, they require encapsulation before being added to a packaging matrix such as liposomes, solid-lipid nanoparticles, nano-emulsions, cyclodextrins, and nanostructured lipid nano-carriers. This article is focused on the encapsulation of EOs in different types of nanocarriers. Nanocarriers can improve the efficiency of active substances by providing protection, stability, and controlled and targeted release. The advantages of the many types of nanocarriers that contain active substances that can be used to make antibacterial and antioxidant biopolymeric-based active packaging are discussed. A nanocarrier-encapsulated EO enables the controlled release of oil, stabilizing the packaging for a longer duration.

Multicharged cyclodextrin supramolecular assemblies

Multicharged cyclodextrin (CD) supramolecular assemblies, including those based on positively/negatively charged modified mono-6-deoxy-CDs, per-6-deoxy-CDs, and random 2,3,6-deoxy-CDs, as well as parent CDs binding positively/negatively charged guests, have been extensively applied in chemistry, materials science, medicine, biological science, catalysis, and other fields. In this review, we primarily focus on summarizing the recent advances in positively/negatively charged CDs and parent CDs encapsulating positively/negatively charged guests, especially the construction process of supramolecular assemblies and their applications. Compared with uncharged CDs, multicharged CDs display remarkably high antiviral and antibacterial activity as well as efficient protein fibrosis inhibition. Meanwhile, charged CDs can interact with oppositely charged dyes, drugs, polymers, and biomacromolecules to achieve effective encapsulation and aggregation. Consequently, multicharged CD supramolecular assemblies show great advantages in improving drug-delivery efficiency, the luminescence properties of materials, molecular recognition and imaging, and the toughness of supramolecular hydrogels, in addition to enabling the construction of multistimuli-responsive assemblies. These features are anticipated to not only promote the development of CD-based supramolecular chemistry but also contribute to the rapid exploitation of these assemblies in diverse interdisciplinary applications.

Ratiometric Thermometers Based on Rhodamine B and Fluorescein Dye-Incorporated (Nano) Cyclodextrin Metal-Organic Frameworks

Macro- and nanosized core, as well as core-shell, γ-cyclodextrin metal-organic frameworks (γ-CD-MOFs) have been designed and used as platforms for the encapsulation of dye molecules to develop the first CD-MOF-based ratiometric optical thermometer materials. A novel dye combination was employed for this purpose, i.e., the duo rhodamine B (RhB) and fluorescein (FL). RhB is highly temperature-sensitive, whereas FL is less temperature-sensitive, and its luminescence emission peak is used as a reference. Promising results in terms of thermometric properties were obtained for a series of dye-encapsulated γ-CD-MOF materials based on this dye combination, with high relative sensitivities, even up to 5%K^-1, for the dye-encapsulated 75%RhB-25%FL nanosized γ-CD-MOF, among the highest performance values reported so far for luminescent dual thermometers. In our study, we have additionally developed a simple yet effective preparation method for core-shell γ-CD-MOFs, allowing effective manipulation of the γ-CD-MOF shell growth. The proposed method allows incorporation of the FL and RhB dyes in the γ-CD-MOFs in a more controlled manner, enhancing the efficiency of the developed ratiometric (macro) γ-CD-MOF thermometers.

Topological defects in polycrystalline hexosomes from β-cyclodextrin fatty esters

Colloidal nanoparticles were prepared by aqueous self-assembly of amphiphilic β-cyclodextrins (βCDs) acylated on their secondary face with C₁₄ chains to a total degree of substitution of 7.0, via a thermolysin-catalyzed transesterification process. The small-angle X-ray scattering pattern of the nanoparticles was consistent with a reverse hexagonal organization. Cryo-transmission electron microscopy images revealed particles with spectacular tortuous shapes and consisting of misoriented domains with a regular columnar hexagonal structure, separated by sharp interfaces. Edge dislocations as well as a variety of stepped tilt grain boundaries (GBs) composed of symmetrical and asymmetrical sections, together with one twist GB, were identified from axial views of the columnar organization. The tilt GB structure was analyzed using the concepts of coincidence site lattice and structural units developed to describe the atomic structure of interfaces in various types of polycrystals. The tilt GBs were described using sequences of βCD-C₁₄ columns that differed by the number of neighboring columns (5, 6 or 7) and exhibiting distinctive contrasts. To our knowledge, this is the first time that these types of topological defects are described at the nanometric scale by direct observation of colloidal polycrystalline hexosomes of self-organized amphiphiles.

Preparation of MSZ Hydrogel and Its Treatment of Colitis

In order to control the release of mesalazine (MSZ) in the gastrointestinal tract to achieve better pharmacological effects in the colon, in this study, MSZ was added to hydroxypropyl-β-cyclodextrin (HP-β-CD) to form a water-soluble HP-β-CD/MSZ inclusion complex. Then, the inclusion compound was loaded into the structure of the bilayer polyelectrolyte complex microsphere formed by alginate (Alg), chitosan (Cs), and kappa carrageenan (κ-Car) as the hydrogel carrier, and the hydrogel beads with colon-specific release MSZ after oral administration were formed. The formed hydrogel beads have different swelling capabilities in different pH media and have the greatest swelling degree under pH 7.4. The encapsulation efficiency and drug loading of hydrogel beads can reach up to 83.23 and 18.31%, respectively, and the size of hydrogel beads can be reduced to less than 1 mm after drying, so that the size of oral administration can be reached. In vivo experiments also showed that the formed hydrogel beads had a better therapeutic effect on colitis than free drugs, and the microspheres were biodegradable, so the double-layer pH-sensitive microspheres could be effectively used in colon-targeting drug delivery.

Modifications of polysaccharide-based biomaterials under structure-property relationship for biomedical applications

Polysaccharides are well accepted biomaterials that have attracted considerable attention. Compared with other materials under research, polysaccharides show unique advantages: they are available in nature and are normally easily acquired, those acquired from nature show favorable immunogenicity, and are biodegradable and bioavailable. The bioactivity and possible applications are based on their chemical structure; however, naturally acquired polysaccharides sometimes have unwanted flaws that limit further applications. For this reason, carefully summarizing the possible modifications of polysaccharides to improve them is crucial. Structural modifications can not only provide polysaccharides with additional functional groups but also change their physicochemical properties. This review based on the structure-property relation summarizes the common chemical modifications of polysaccharides, the related bioactivity changes, possible functionalization methods, and major possible biomedical applications based on modified polysaccharides.

Principles and applications of cyclodextrin liquid crystals

Cyclodextrin-based liquid crystals and their emerging applications are described in this tutorial review, which covers reports from the last decade with a focus on recent developments. Although cyclodextrins are among the best studied macrocyclic host molecules and liquid crystals have found widespread technological application, the integration of cyclodextrins in liquid crystals as versatile supramolecular materials has been barely explored. However, in the last few years promising innovations in molecular design as well as proof-of-concept applications such as ion-conductive and proton-conductive liquid crystals, nanoparticle additives for liquid crystal display technology, polyrotaxane-based liquid crystals and liquid crystal-based sensors have been reported. We discuss various examples of cyclodextrin-based liquid crystals that demonstrate the significant potential of these unique soft materials for future research and interdisciplinary applications.

Role of Calixarene in Chemotherapy Delivery Strategies

Since cancer is a multifactorial disease with a high mortality rate, the study of new therapeutic strategies is one of the main objectives in modern research. Numerous chemotherapeutic agents, although widely used, have the disadvantage of being not very soluble in water or selective towards cancerous cells, with consequent side effects. Therefore, in recent years, a greater interest has emerged in innovative drug delivery systems (DDSs) such as calixarene, a third-generation supramolecular compound. Calixarene and its water-soluble derivatives show good biocompatibility and have low cytotoxicity. Thanks to their chemical–physical characteristics, calixarenes can be easily functionalized, and by itself can encapsulate host molecules forming nanostructures capable of releasing drugs in a controlled way. The encapsulation of anticancer drugs in a calixarene derivate improves their bioavailability and efficacy. Thus, the use of calixarenes as carriers of anticancer drugs could reduce their side effects and increase their affinity towards the target. This review summarizes the numerous research advances regarding the development of calixarene nanoparticles capable of encapsulating various anticancer drugs.

UV SPECTROSCOPY AND KINETIC RESEARCH OF PHOTODEGRADATION OF METHYL ORANGE IN THE PRESENCE OF TITANIUM DIOXIDE AND β-CYCLODEXTRIN OR ITS DERIVATIVES

The research is devoted to the study of the effect of β-cyclodextrin (β-CD) and its derivatives on the photocatalytic degradation of methyl orange in aqueous solutions in the presence of titanium dioxide. It has been shown that the kinetics of photodegradation of methyl orange is more accurately described by the pseudo first order equation for all investigated pH values. In the presence of cyclodextrins β-CD and 2-hydroxypropyl-β-cyclodextrin, acceleration of photodegradation was observed only after 30 min of irradiation. As a result, the oxidation of hydroxyl groups of cyclodextrin occurred. A significant slowdown in photodestruction in the TiO2-β-CD sample during the first 45 min is explained by the formation of inclusion complexes of cyclodextrin with methyl orange, which prevented the destruction of dye. The use of the β-cyclodextrin, its derivatives and increasing the acidity of the medium accelerates the processes of photodestruction of methyl orange in distilled and natural waters. Methyl orange was decolorized for 20 – 25 min in solutions of all investigated cyclodextrin derivatives at pH 2.5. The destruction of methyl orange was most effective with the use of sulfobutyl ether β-CD. The bactericidal lamp (λ = 254 nm) allows to increase the rate of destruction during the irradiation process. Methyl orange discolored much faster under the action of a bactericidal lamp than using only ultraviolet lamps with λ = 365 nm. A slight slowdown in the decomposition process is observed after several irradiation cycles. This may be due to the influence of the formed products of destruction. However, under such conditions, the by-products of reactions decompose much faster. The use of cyclodextrins is possible without significant loss of efficiency up to 8 cycles.

Curcumin Encapsulated in Crosslinked Cyclodextrin Nanoparticles Enables Immediate Inhibition of Cell Growth and Efficient Killing of Cancer Cells

The efficiency of anti-cancer drugs is commonly determined by endpoint assays after extended incubation times, often after days. Here we demonstrate that curcumin encapsulated in crosslinked cyclodextrin nanoparticles (CD-NP) acts extremely rapidly on cell metabolism resulting in an immediate and complete inhibition of cell growth and in efficient cancer-cell killing only few hours after incubation. This early onset of anti-cancer action was discovered by live-cell high-throughput fluorescence microscopy using an environmental stage. To date, only very few examples of covalently crosslinked nanoscale CD-based (CD-NP) drug carriers exist. Crosslinking cyclodextrins enables the adsorption of unusually high payloads of hydrophobic curcumin (762 µg CC/mg CD-NP) reflecting a molar ratio of 2.3:1 curcumin to cyclodextrin. We have investigated the effect of CD-NP encapsulated curcumin (CD-CC-NP) in comparison to free, DMSO-derived curcumin nanoparticles (CC-NP) on 4 different cell lines. Very short incubations times as low as 1 h were applied and cell responses after medium change were subsequently followed over two days. We show that cell proliferation is inhibited nearly immediately in all cell lines and that a cell- and concentration dependent cancer-cell killing occurs. Anti-cancer effects were similar with free and encapsulated curcumin, however, encapsulation in CD-NP drastically extends the long-term photostability and anti-cancer activity of curcumin. Curcumin-sensitivity is highest in HeLa cells reaching up to 90% cell death under these conditions. Sensitivity decreased from HeLa to T24 to MDA MB-231 cells. Strikingly, the immortalized non-cancerous cell line MCF-10A was robust against curcumin concentrations that were highly toxic to the other cell lines. Our results underline the potential of curcumin as gentle and yet effective natural anti-cancer agent when delivered solvent-free in stabilizing and biocompatible drug carriers such as CD-NP that enable efficient cellular delivery.

Polycationic cyclodextrin nanoparticles induce apoptosis and affect antitumoral activity in HepG2 cell line: An evaluation at the molecular level

Hepatocellular carcinoma (HCC) is a highly metastatic primary liver cancer generating molecular alterations that end up escaping the apoptotic machinery and conferring multidrug resistance. Targeted medicines with increased and selective cytotoxicity and minimal drug resistance are essential for the treatment of HCC. In this study, a self-assembled polycationic (PC) amphiphilic β-cyclodextrin (βCDC6) nanoparticle formulation was characterized and its efficacy over HCC cell line HepG2 was evaluated in terms of cytotoxicity, apoptotic potential, chemosensitivity and mitochondrial balance utilizing biochemical, gene expression and proteomic approaches without encapsulating an anti-neoplastic agent. Blank PC βCDC6 exerted an anti-proliferative effect on 3D multicellular HepG2 spheroid tumors. These nanoparticles were able to trigger apoptosis proved by caspase 3/7 activity, gene expression and flow cytometry studies. The subjection of PC restored the chemosensitivity of HepG2 cells by suppressing the function of p-glycoprotein. The proteomic studies with Q-TOF LC/MS revealed 73 proteins that are aberrantly encoded after cells were treated with the blank PC. Metabolomic analysis further confirmed the shift in certain biological pathways. Thus, we confirmed that the hepatocellular carcinoma-targeting βCDC6 PC nanoparticles induce apoptosis, lower the rate of cell proliferation, hinder multidrug resistance and they are convenient carriers for eventual therapeutic administrations in HCC patients.

A long-term controlled drug-delivery with anionic beta cyclodextrin complex in layer-by-layer coating for percutaneous implants devices

This study demonstrated a drug-delivery system with anionic beta cyclodextrin (β-CD) complexes to retain tetracycline (TC) and control its release from multilayers of poly(acrylic acid) (PAA) and poly(l-lysine) (PLL) in a ten double layers ([PAA/PLL]₁₀) coating onto titanium. The drug-delivery capacity of the multilayer system was proven by controlled drug release over 15 days and sustained released over 30 days. Qualitative images confirmed TC retention within the layer-by-layer (LbL) over 30 days of incubation. Antibacterial activity of TC/anionic β-CD released from the LbL was established against Staphylococcus aureus species. Remarkably, [PAA/PLL]₁₀/TC/anionic β-CD antibacterial effect was sustained even after 30 days of incubation. The non-cytotoxic effect of the multilayer system revealed normal human gingival fibroblast growth. It is expected that this novel approach and the chemical concept to improve drug incorporation into the multilayer system will open up possibilities to make the drug release system more applicable to implantable percutaneous devices.

Erlotinib entrapped in cholesterol-depleting cyclodextrin nanoparticles shows improved antitumoral efficacy in 3D spheroid tumors of the lung and the liver

Erlotinib (ERL), a tyrosine kinase inhibitor approved for therapeutic use in non-small cell lung cancer is further researched for eventual liver cancer treatment. However, conventional ERL has important bioavailability problems resulting from oral administration, poor solubility and gastrointestinal degradation into inactive metabolites. Alternative administration routes and nanoparticulate drug delivery systems are studied to prevent or reduce these drawbacks. In this study, ERL-loaded CD nanosphere and nanocapsule formulations capable of cholesterol depletion in resistant cancer cells were evaluated for ERL delivery. Drug loading and release profile depended largely on the surface charge of nanoparticles. Antiproliferative activity data obtained from 2D and 3D cell culture models demonstrated that polycationic βCD nanocapsules were the most effective formulation for ERL delivery to lung and liver cancer cells. 3D tumour tumoral penetration studies further revealed that nanocapsule formulations penetrated deeper into the tumour through the multilayered cells. Furthermore, all formulations were able to extract membrane cholesterol from lung and liver cancer cell lines, indicating the induction of apoptosis and overcoming drug resistance. In conclusion, given their tumoral penetration and cell membrane cholesterol depletion abilities, amphiphilic CD nanocapsules emerge as promising alternatives to improve the safety and efficiency of ERL treatment of both liver and lung tumours.

CD Oxyanions as a Tool for Synthesis of Highly Anionic Cyclodextrin Polymers

Water soluble highly anionic β-cyclodextrin-based polymers were synthesized by reaction between cyclodextrin oxyanion and pyromellitic anhydride. The synthesis method utilizes activation hydroxyl groups in anhydrous glucopyranosyl units (AGU) in the DMF solution with the use of NaH. In these conditions, like in the case of the cyclodextrin reactions in the highly alkaline media, there is a nucleophilic substitution of difunctional compounds, which develops a polymer network with various cyclodextrin substitution. Different molar ratios of the reagents were investigated in terms of molecular size, chemical structure and water solubility of the polymers. The separation of the polymer due to particle size by ultrafiltration process and HPSEC-MALLS-RI and MALDI-TOF MS measurements for molecular mass analysis were employed. The IR, H NMR, SEM, DSC and TG measurements were taken for the structural characterization of the polymers. Additionally, the solubility test and metal ion complexation processes were also investigated in a wide range of pH. These polymers could be used in several areas such as: improving the aqueous solubility of poor water-soluble molecules, removing heavy metals from waste water, protecting degradable substances or synthesizing new drug delivery systems.

Shell-by-Shell Functionalization of Inorganic Nanoparticles

The current state of the hierarchical chemical functionalization of inorganic nanoparticles (NPs) by shell-by-shell (SbS)-assembly of organic layers around the NP cores is summarized. This supramolecular functionalization concept is based on two steps: 1) the covalent grafting of a first ligand-shell consisting of, for example, long chain phosphonic acids and 2) the noncovalent interdigitation of amphiphiles forming the second ligand shell. The latter process is guaranteed predominantly by solvophobic interactions. These highly order organic-inorganic hybrid architectures are currently an emerging field at the interface of synthetic chemistry, nanotechnology, and materials science. The doubly functionalized NPs display tunable materials properties, such a controlled dispersibility and stability in various solvents, highly efficient trapping of guest molecules in between the ligand shells (water cleaning) as well as compartmentalization and modification of electronic interactions between photoactive components integrated in such complex nano-architectures. Such SbS-functionalized NPs have a high potential as water-cleaning materials and also some first prototype applications as biomedicinal therapeutics have been presented.

Efficient modification of PAMAM G1 dendrimer surface with β-cyclodextrin units by CuAAC: impact on the water solubility and cytotoxicity

The toxicity of the poly(amidoamine) dendrimers (PAMAM) caused by the peripheral amino groups has been a limitation for their use as drug carriers in clinical applications. In this work, we completely modified the periphery of PAMAM dendrimer generation 1 (PAMAM G1) with β-cyclodextrin (β-CD) units through the Cu(i)-catalyzed azide–alkyne cycloaddition (CuAAC) to obtain the PAMAM G1-β-CD dendrimer with high yield. The PAMAM G1-β-CD was characterized by ¹H- and ¹³C-NMR and mass spectrometry studies. Moreover, the PAMAM G1-β-CD dendrimer showed remarkably higher water solubility than native β-CD. Finally, we studied the toxicity of PAMAM G1-β-CD dendrimer in four different cell lines, human breast cancer cells (MCF-7 and MDA-MB-231), human cervical adenocarcinoma cancer cells (HeLa) and pig kidney epithelial cells (LLC-PK1). The PAMAM G1-β-CD dendrimer did not present any cytotoxicity in cell lines tested which shows the potentiality of this new class of dendrimers.

The toxicity of the poly(amidoamine) dendrimers (PAMAM) caused by the peripheral amino groups has been a limitation for their use as drug carriers in clinical applications.

Preparation and characterization of cyclodextrin nanosponges for organic toxic molecule removal

Cyclodextrin-based nanosponges (CD-NS) are considered as safe and biocompatible systems for removing toxic molecules from the body. Rapid removal of toxic molecules that are formed in the body from certain food constituents, is relevant especially for patients affected by chronic kidney disease. Within the scope of this study, innovative cyclodextrin polymers were synthesized to form nanosponges able to remove indole, before it could form the toxic indoxyl sulfate in the body. Furthermore, in vivo studies were carried out using the two optimal CD-NS formulations by assessing physicochemical properties, stability, indole adsorption capacity and in vitro cytotoxicity. NS prepared from β-cyclodextrin cross-linked with toluene diisocyanate was found to be the most effective NS with an in vitro indole adsorption capacity of over 90%. In addition, this derivative was more stable in gastrointestinal media. Animal studies further revealed that oral CD-NSs did not tend to accumulate and damage gastrointestinal tissues and are excreted from the GI tract with minimal absorption. In conclusion, this study suggests that CD-NS formulations are effective and safe in removing toxic molecules from the body. Their potential use in veterinary or human medicine could reduce dialysis frequency and avoid hepatic and cardiac toxicity avoiding the indole formation.

Cyclodextrin nanoparticle bound oral camptothecin for colorectal cancer: Formulation development and optimization

Chemotherapeutic drugs for colorectal cancer(CRC) which is currently the third most lethal cancer globally, are administered intravenously (iv) due to their low oral bioavailability resulting from their physicochemical properties. Non-selective biodistribution and difficulties of parenteral administration reduce treatment efficacy. The aim of this work is to develop cyclodextrin (CD) based cationic nanoparticles (NPs) for CRC treatment with model drug camptothecin (CPT) that can be administered orally, protecting CPT through gastrointestinal tract (GIT), accumulating at mucus layer and providing an effective local treatment for the tumor area. NPs using two different amphiphilic CDs were prepared and coated with polyethylenimine (PEI) or chitosan (CS) to obtain positively charged surface for all formulations. Pre-formulation studies resulted in optimal formulation, CPT loaded Poly-β-CD-C6 NPs, with 135 nm diameter and zeta potential of + 40 mV. In vitro release study was designed to represent gastrointestinal pH and transit time revealing 52% of encapsulated CPT successfully delivered all the way to simulated colon. CPT bound to Poly-β-CD-C6 NPs exhibited higher cytotoxicity on HT-29 cells compared to equivalent CPT in solution. Caco-2 cell permeability studies showed 276% increase in CPT permeability and significantly higher mucosal penetration in cationic CD nanoparticle form.

COVID-19: A Recommendation to Examine the Effect of Mouthrinses with β-Cyclodextrin Combined with Citrox in Preventing Infection and Progression

Considered to be a major portal of entry for infectious agents, the oral cavity is directly associated with the evolutionary process of SARS-CoV-2 in its inhalation of ambient particles in the air and in expectorations. Some new generations of mouth rinses currently on the market have ingredients that could contribute to lower the SARS-CoV-2 viral load, and thus facilitate the fight against oral transmission. If chlorhexidine, a usual component of mouth rinse, is not efficient to kill SARS-CoV-2, the use of a mouth rinses and/or with local nasal applications that contain β-cyclodextrins combined with flavonoids agents, such as Citrox, could provide valuable adjunctive treatment to reduce the viral load of saliva and nasopharyngeal microbiota, including potential SARS-CoV-2 carriage. We urge national agencies and authorities to start clinical trials to evaluate the preventive effects of βCD-Citrox therapeutic oral biofilm rinses in reducing the viral load of the infection and possibly disease progression.

Liposomal membrane permeability assessment by fluorescence techniques: Main permeabilizing agents, applications and challenges

Liposomes are lipid vesicles made of one or multiple lipid bilayers surrounding an internal aqueous core. They are broadly employed as models to study membrane structure and properties. Among these properties, liposome membrane permeability is crucial and widely assessed by fluorescence techniques. The first part of this review is devoted to describe the various techniques used for membrane permeability assessment. Attention is paid to fluorescence techniques based on vesicle leakage of self-quenching probes, dye/quencher pair or cation/ligand pair. Secondly, the membrane-active agents inducing membrane permeabilization is presented and details on their mechanisms of action are given. Emphasis is also laid on the intrinsic and extrinsic factors that can modulate the membrane permeability. Hence, a suitable liposomal membrane should be formulated according to the aim of the study and its application.