Ferroelectric hydrogels from amino acids and oleic acid

Ferroelectric bio-based materials with a high water content (≈90 wt %) were not previously developed. Here, we develop hydrogels containing ≈90 wt % water, amino acids (lysine and arginine) and oleic acid. The NH and CH groups of lysine hydrogen bond water, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy, yielding electrically conductive solutions. Lysine also interacts with oleic acid, yielding hard materials with a lamellar crystal structure, as revealed by synchrotron small angle X-ray scattering. Polarized light microscopy and shear rheology show that aqueous mixtures of amino acids and oleic acid are birefringent gels. These gels have a columnar, hexagonal crystal structure with 54-85 wt % water, and a bi-continuous sponge crystal structure with 89 wt % water. They are piezoelectric, as demonstrated by cyclic voltammetry. Thus, they deform and undergo crystalline phase transitions when exposed to electric fields. The piezoelectric materials developed can find use in medical applications and clean energy harvesting.

Investigation of Host-Guest Inclusion Complex of Mephenesin with α-Cyclodextrin for Innovative Application in Biological System

The goal of this study was to use coevaporation to look into how polyether compounds like mephenesin (MEP) can be encapsulated into the host molecule α-cyclodextrin's nanohydrophobic cage. Fourier transform infrared spectroscopy (FT-IR) investigations, powder X-ray diffraction (PXRD), and 1H NMR were among the spectroscopic techniques used to describe the inclusion complex. Additionally, Job's plot has been utilized to illustrate how MEP is encapsulated with α-cyclodextrin (α-CD) at a 1:1 molar ratio. The thermal stability of MEP increased after encapsulation according to thermogravimetric analysis (TGA) and differential thermal analysis (DTA) experiments. Mephenesin fits into the cavity of α-cyclodextrin in a 1:1 ratio, as observed by molecular docking for the inclusion complex to find the most appropriate orientation. This observation is further supported by the Job plot. Furthermore, a comparison was carried out based on a cell viability study between the medication and its inclusion complex.

Evaluating the Potential of Cyclodextrins in Reducing Aggregation of Antibody-Drug Conjugates with Different Payloads

Cyclodextrins (CDs) are versatile agents used to solubilize small drugs and stabilize proteins. This dual functionality may be particularly beneficial for antibody-drug conjugates (ADCs), as CDs may "mask" the hydrophobicity of the drug payloads. In this study, we explored the effect of CDs on the physical stability of ADCs composed of the same antibody but with different payloads (maytansinoid, auristatin, and fluorophore payloads). The aggregation of ADCs was evaluated under shaking stress conditions and elevated temperatures using size-exclusion chromatography, turbidity, and backgrounded membrane imaging. Our results showed that hydroxypropyl-(HP)-CDs effectively stabilized all ADCs during shaking stress, with increasing stabilization in the order of HPαCD < HPγCD < HPβCD at concentrations of 7.5 mM and (near) complete stabilization at 75 mM. Native CDs without surface activity also stabilized certain ADCs, although less effectively than HP-CDs under agitation stress. During quiescent incubation, the HP-CD effects were small for most ADCs. However, for an ADC with a fluorophore payload that rapidly aggregated after conjugation, HPγCD substantially reduced aggregate levels, in line with fluorescence data supporting CD-ADC interactions. In contrast, sulfobutylether-β-CD (SBEβCD) increased the aggregation rates in all ADCs under all stress conditions. In conclusion, this study highlights the potential of appropriate CD formulations to improve the physical stability of ADCs.

Exploring inclusion complex of an anti-cancer drug (6-MP) with β-cyclodextrin and its binding with CT-DNA for innovative applications in anti-bacterial activity and photostability optimized by computational study

The co-evaporation approach was used to examine the host-guest interaction and to explore the cytotoxic and antibacterial properties of an important anti-cancer medication, 6-mercaptopurine monohydrate (6-MP) with β-cyclodextrin (β-CD). The UV-Vis investigation confirmed the inclusion complex's (IC) 1 : 1 stoichiometry and was also utilized to oversee the viability of this inclusion process. FTIR, NMR, and XRD, among other spectrometric techniques, revealed the mechanism of molecular interactions between β-CD and 6-MP which was further hypothesized by DFT to verify tentative outcomes. TGA and DSC studies revealed that 6-MP's thermal stability increased after encapsulation. Because of the protection of drug 6-MP by β-CD, the formed IC was found to have higher photostability. This work also predicts the release behavior of 6-MP in the presence of CT-DNA without any chemical changes. An evaluation of the complex's antibacterial activity in vitro revealed that it was more effective than pure 6-MP. The in vitro cytotoxic activity against the human kidney cancer cell line (ACHN) was also found to be significant for the IC (IC50 = 4.18 μM) compared to that of pure 6-MP (IC50 = 5.49 μM). These findings suggest that 6-MP incorporation via β-CD may result in 6-MP stability and effective presentation of its solubility, cytotoxic and antibacterial properties.

Application of γ-cyclodextrin-lysozyme as host materials for encapsulation of curcumin: characterization, stability, and controlled release properties

BACKGROUND

In this study, a safe and relatively stable γ-cyclodextrin-lysozyme (γ-CD-Lys) was synthesized using epichlorohydrin as the cross-linking agent, and curcumin was successfully encapsulated in γ-CD-Lys.

RESULTS

The successful Lys grafting onto γ-CD can be demonstrated by a high grafting ratio (79.02%) and was further confirmed by Fourier transform infrared (FTIR) band shifts and the new signal obtained at δ 2.75 in proton nuclear magnetic resonance. The encapsulation efficiency value of γ-CD-Lys was 76.74%, and the successful encapsulation of curcumin into γ-CD-Lys was confirmed by crystal structure change, increased melting point, and FTIR band shifts. The intermolecular bonds results suggested that associative forces between curcumin and γ-CD-Lys were electrostatic interaction, hydrogen bonds interaction, and hydrophobic interaction. The designed nanoparticles had excellent stability at low pH and low salt concentration. The release rate of these nanoparticles was inhibited in simulated gastric conditions, whereas it increased significantly in intestinal media. Simulated gastrointestinal digestion experiments further confirmed that nanoparticles showed higher bioaccessibility (86.05%) compared with curcumin (58.82%).

CONCLUSION

Overall, our study showed that the nanoparticles were highly promising for delivering curcumin because of their enhanced functional attributes and stabilization in acid or low salt environments. Also, it was an excellent wall material for targeting hydrophobic bioactive compounds in the intestinal tract via oral administration. © 2022 Society of Chemical Industry.

Probing the Molecular Assembly of a Metabolizer Drug with β-Cyclodextrin and Its Binding with CT-DNA in Augmenting Antibacterial Activity and Photostability by Physicochemical and Computational Methodologies

The assembly of an inclusion complex in an aqueous medium using a metabolizer drug (dyphylline) as guest and β-cyclodextrin as host has been established, which is extremely appropriate for a variety of applications in modern biomedical sciences. The formation of the inclusion complex is established by ¹H NMR, and surface tension and conductivity measurements demonstrate that the inclusion complex was produced with 1:1 stoichiometry. The thermodynamic parameters based on density, viscosity, and refractive index measurements were used to determine the nature of the complex. This research also forecasts how dyphylline will release in the presence of CT-DNA without any chemical modifications. The produced insertion complex (IC) has a higher photostability due to the drug dyphylline being protected by β-CD. The antibacterial activity of dyphylline greatly improved after complexation and exhibited higher toxicity against Gram-negative (highest against Escherichia coli) in comparison to Gram-positive bacteria. The encapsulation mode of the dyphylline molecule into the cavity of the β-CD was also investigated using DFT to confirm preliminary results.

Chemiluminescent self-reporting supramolecular transformations on macromolecular scaffolds

We introduce the synthesis of a self-reporting system with chemiluminescent output, which is regulated via dynamic supramolecular complex formation.

Probing Inclusion Complexes of Pentoxifylline and Pralidoxim inside Cyclic Oligosaccharides by Physicochemical Methodologies

Structurally different Molecules namely Pentoxifylline and Pralidoxim were chosen along with α-cyclodextrin and β-cyclodextrin to study host-guest inclusion phenomena. The formations of host guest inclusion complexes were confirmed by studying 1H-NMR spectra, FT-IR spectra, apparent molar volume and viscosity co-efficient. The stabilities of inclusion complexes were compared calculating the binding constant from UV-VIS spectroscopic study. The 1:1 stoichiometry of the inclusion complexes were also determined by analysing the Jobs plot and surface tension data. The values for Gibbs’ free energy were found negative for both the processes. Based on all the above experiments the inclusion processes were found feasible for both the compounds. These types of inclusion complexes are of high interest in the field of research and industry as these are used as drug delivery systems.

Distinguishing enantiomeric amino acids with chiral cyclodextrin adducts and structures for lossless ion manipulations

Enantiomeric molecular evaluations remain an enormous challenge for current analytical techniques. To date, derivatization strategies and long separation times are generally required in these studies, and the development and implementation of new approaches are needed to increase speed and distinguish currently unresolvable compounds. Herein, we describe a method using chiral cyclodextrin adducts and structures for lossless ion manipulations (SLIM) and serpentine ultralong path with extended routing (SUPER) ion mobility (IM) to achieve rapid, high resolution separations of d and l enantiomeric amino acids. In the analyses, a chiral cyclodextrin is added to each sample. Two cyclodextrins were found to complex each amino acid molecule (i.e. potentially sandwiching the amino acid in their cavities) and forming host-guest noncovalent complexes that were distinct for each d and l amino acid pair studied and thus separable with IM in SLIM devices. The SLIM was also used to accumulate much larger ion populations than previously feasible for evaluation and therefore allow enantiomeric measurements of higher sensitivity, with gains in resolution from our ultralong path separation capabilities, than previously reported by any other IM-based approach.

Study to Probe Subsistence of Host-Guest Inclusion Complexes of α and β-Cyclodextrins with Biologically Potent Drugs for Safety Regulatory Dischargement

Host-guest interaction of two significant drugs, phenylephrine hydrochloride and synephrine with α and β-cyclodextrins were studied systematically. Initially two simple but reliable physicochemical techniques namely conductance and surface tension were employed to find out saturation concentration for the inclusion and its stoichiometry. The obtained 1:1 stoichiometry was further confirmed by two spectrometric methods, UV-Vis study and spectrofluorimetry. Significant shifts in IR stretching frequency also support the inclusion process. Relative stabilities of the inclusion complexes were established by the association constants obtained from UV-Vis spectroscopic measurements, program based mathematical calculation of conductivity data. Calculations of the thermodynamic parameters dictates thermodynamic feasibility of the inclusion process. Spectrofluorometric measurement scaffolds the UV-Vis spectroscopic measurement validating stability of the ICs once again. Mass spectroscopic measurement gives the molecular ion peaks corresponding to the inclusion complex of 1:1 molar ratio of host and guest molecules. The mechanism of inclusion was drawn by ¹H-NMR and 2D ROESY spectroscopic analysis. Surface texture of the inclusion complexes was studied by SEM. Finally, the cytotoxic activities of the inclusion complexes were analyzed and found, Cell viability also balances for non-toxic behavior of the ICs. Moreover, all the studies reveal the formation of inclusion complexes of two ephedra free, alternatively emerging drugs (after their banned product having ephedra) SNP, PEH with α and β-CD which enriches the drug delivery system with their regulatory release without any chemical modification.

Host–guest complexation of ionic liquid with α- and β-cyclodextrins: a comparative study by 1H-NMR, 13C-NMR and COSY

The inclusion complexation of 1-butyl-3-methylimidazolium octylsulphate [Bmim][OS] with host α- and β-cyclodextrins (CDs) has been explored by ¹H NMR, ¹³C NMR and COSY methods. The insertion of a guest molecule into the cavity of CD is clearly reflected by changes in ¹H-NMR and ¹³C-NMR chemical shift values and COSY NMR suggest that both H-bonding and electrostatic interactions involved to the complexation.

Binding and Selectivity of Essential Amino Acid Guests to the Inverted Cucurbit[7]uril Host

Interactions between inverted cucurbit[7]uril (iQ[7]) and essential amino acids have been studied at pH = 7.0 by ¹H NMR spectroscopy, electronic absorption spectroscopy, isothermal titration calorimetry, and mass spectrometry. The interactions can be divided into three binding types at pH = 7.0. Experimental results from the present study showed that the host displays a strong binding to the aromatic amino acids, Trp and Phe, and the guests of Lys, Arg, and His lie outside the cavity portal of the host. Meanwhile, the alkyl moieties of the guests Met, Leu, and Ile were accommodated within the cavity of iQ[7], but there was no significant interaction between iQ[7] and Thr or Val. The complexation behavior of iQ[7] with essential amino acids was explored at pH = 3, and the binding of Lys, Arg, and His revealed an unexpected behavior, with their side chains located in the cavity of iQ[7], whereas those of the aromatic Trp and Phe were deeper within the iQ[7] cavity. The alkyl side chains of the guests Met, Leu, Ile, Thr, and Val were also located inside the iQ[7] cavity and formed the host-guest complexes.

Study on Host-Guest Inclusion Complexation of a Drug in Cucurbit [6]uril

Assembly of pyridine-2-aldoxime drug with cucurbit [6]uril (CB[6]) has been investigated by 1H-NMR and 2D-ROESY NMR, UV-Vis spectroscopy, FT-IR spectroscopy, surface tension and conductivity measurements in aqueous saline environment. The distinct cationic receptor feature and the cavity dimension of the CB[6] emphasize that the macro-cyclic host molecule remain as complex with the nerve stimulus drug molecule. The results obtained from surface tension and specific conductivity measurements suggest 1:1 inclusion complex formation between drug and CB[6]. The stability constant evaluated by UV-Vis spectroscopic approach is 2.21×105 M−1 at 298.15 K, which indicates that the complex is sufficiently stable at physiological temperature.

Free-energy patterns in inclusion complexes: the relevance of non-included moieties in the stability constants

A MD/PMF-based procedure is designed for quantification of the interaction and respective components, guiding complex formation in water between β-CD and several naphthalene derivatives, highlighting the relevance of substituents.

Inclusion complexes of norepinephrine with β-cyclodextrin, 18-crown-6 and cucurbit[7]uril: experimental and molecular dynamics study

Binary and ternary complexes of norepinephrine with 18C6, βCD and CB7 have been characterized using various experimental and theoretical techniques.

Cage to cage study of ionic liquid and cyclic oligosaccharides to form inclusion complexes

Encapsulation of trihexyltetradecylphosphonium chloride inside α and β-cyclodextrins in both aqueous solution and solid state with 1 : 1 stoichiometry.

Study to explore the mechanism to form inclusion complexes of β-cyclodextrin with vitamin molecules

Host–guest inclusion complexes of β-cyclodextrin with two vitamins viz., nicotinic acid and ascorbic acid in aqueous medium have been explored by reliable spectroscopic, physicochemical and calorimetric methods as stabilizer, carrier and regulatory releaser of the guest molecules. Job’s plots have been drawn by UV-visible spectroscopy to confirm the 1:1 stoichiometry of the host-guest assembly. Stereo-chemical nature of the inclusion complexes has been explained by 2D NMR spectroscopy. Surface tension and conductivity studies further support the inclusion process. Association constants for the vitamin-β-CD inclusion complexes have been calculated by UV-visible spectroscopy using both Benesi–Hildebrand method and non-linear programme, while the thermodynamic parameters have been estimated with the help of van’t Hoff equation. Isothermal titration calorimetric studies have been performed to determine the stoichiometry, association constant and thermodynamic parameters with high accuracy. The outcomes reveal that there is a drop in ΔS^o, which is overcome by higher negative value of ΔH^o, making the overall inclusion process thermodynamically favorable. The association constant is found to be higher for ascorbic acid than that for nicotinic acid, which has been explained on the basis of their molecular structures.

Probing inclusion complexes of cyclodextrins with amino acids by physicochemical approach

Formations of host-guest inclusion complexes of two natural amino acids, viz., l-Leucine and l-Isoleucine as guests with α and β-cyclodextrins have been investigated which include diverse applications in modern science such as controlled delivery in the field of pharmaceuticals, food processing etc. Surface tension and conductivity studies establish the formation of inclusion complexes with 1:1 stoichiometry. The interactions of cyclodextrins with amino acids have been supported by density, viscosity, refractive index, hydration and solvation number measurements indicating higher degree of inclusion in case of α-cyclodextrin. l-Leucine interacts more with the hydrophobic cavity of cyclodextrin than its isomer. With the help of stability constant by NMR titration, hydrophobic effect, H-bonds and structural effects the formations of inclusion complexes have been explained.

Insertion behavior of imidazolium and pyrrolidinium based ionic liquids into α and β-cyclodextrins: mechanism and factors leading to host–guest inclusion complexes

The encapsulation of [BMIm]Cl and [BMP]Cl within α and β-cyclodextrin in both the solid state and aqueous solution with 1 : 1 supramolecular assembly.

Host–guest inclusion complexes of RNA nucleosides inside aqueous cyclodextrins explored by physicochemical and spectroscopic methods

Spectroscopic and physicochemical studies reveal formation of host–guest inclusion complexes of RNA nucleosides inside hydrophobic cavity of α and β-cyclodextrins.