Search Results (530)

Fabricating breast tumor models that mimic the natural breast tissue-like microenvironment (normal or cancerous) both physically and bio-metabolically, despite extended research, is still a challenge. A native-mimicking breast tumor model is the demand since complex biophysiological mechanisms in the native breast tissue hinder deciphering the root causes of cancer initiation and progression. Hydrogels, which mimic the natural extracellular matrix (ECM), are increasingly demanded for various biomedical applications, including tissue engineering and tumor modeling. Their biomimetic 3D network structures have demonstrated significant potential to enhance the breast tumor model, treatment, and recovery. Additionally, 3D tumor organoids cultivated within hydrogels maintain the physical and genetic traits of native tumors, offering valuable platforms for personalized medicine and therapy response evaluation. Hydrogels are broadly classified into static and dynamic hydrogels. Static hydrogels, however, are inert to external stimuli and do not actively participate in biological processes or provide scaffolding systems. Dynamic hydrogels, on the other hand, adapt and respond to the surrounding microenvironment or even create new microenvironments according to physiological cues. Dynamic hydrogels typically involve reversible molecular interactions—through covalent or non-covalent bonds—enabling the fabrication of hydrogels tailored to meet the mechanical and physiological properties of target tissues. Although both static and dynamic hydrogels can be advanced by incorporating active nanomaterials, their combinations with dynamic hydrogels provide enhanced functionalities compared to static hydrogels. Further, engineered hydrogels with adipogenic and angiogenic properties support tissue integration and regeneration. Hydrogels also serve as efficient delivery systems for chemotherapeutic and immunotherapeutic agents, enabling localized, sustained release at tumor sites. This approach enhances therapeutic efficacy while minimizing systemic side effects, supporting ongoing research into hydrogel-based breast cancer therapies and reconstructive solutions. This review summarizes the roles of dynamic hydrogels in breast tumor models. Furthermore, this paper discusses the advantages of integrating nanoparticles with dynamic hydrogels for drug delivery, cancer treatment, and other biomedical applications, alongside the challenges and future perspectives. Full article

Corbicula fluminea protein (CFP) and cyanidin-3-O-glucoside (C3G) are natural nutrient fortifiers. During consumption or processing, they may interact with each other, inducing alternations in their structural and functional properties. However, nothing was known about the mechanism of their interaction and their synergistic antioxidant effect. In this research, C3G was physically mixed with CFP to simulate practical scenarios. The impact of the presence of C3G on the multispectral characteristics, antioxidant activity, and particle properties of CFP was examined and compared to chemically fabricated C3G-CFP covalent conjugates. The results indicate that C3G tended to spontaneously bind to CFP and formed compact non-covalent complex, with hydrophobic forces predominantly governing the interaction. This binding resulted in the statically quenched intrinsic fluorescence of CFP, accompanied by a dynamic model. Moreover, C3G preferentially induced Trp residue in CFP exposed to a more polar microenvironment, yet it exerted nearly no effects on CFP when analyzed using ultraviolet–visible (UV-Vis) spectroscopy and synchronous fluorescence spectroscopy (SFS). Additionally, although the formed non-covalent complex demonstrated strengthened antioxidant capacity, C3G displayed an antagonistic effect with CFP, whereas lower C3G concentrations led to synergistic effects in covalent conjugates. These findings provide new insights into the effective application of C3G and CFP as nutritional antioxidants. Full article

Carmustine (BCNU) is a powerful alkylating agent primarily used in the chemotherapeutic treatment of malignant brain tumors. However, its clinical application faces significant constraints due to its lipophilicity, low thermal stability, and rapid degradation in physiological environments. To tackle these challenges, our research aimed at the development and detailed characterization of α-cyclodextrin (α-CD) inclusion complexes (ICs) with BCNU employing three different synthesis techniques: co-grinding, cryomilling, and co-precipitation. The selected synthetic methods displayed variations dependent on the technique used, affecting the efficiency, inclusion ratios, and drug-loading capacities, with co-precipitation achieving the most favorable complexation parameters. Structural elucidation through ¹H NMR chemical shifts analysis indicated that only partial inclusion of BCNU occurred within α-CD in ICs produced via co-grinding, while cryomilling and co-precipitation allowed for complete inclusion. Multimodal spectroscopic analyses (FT-IR, UV-Vis, ¹³C CP MAS NMR, and ESI-MS) further substantiated the effective encapsulation of BCNU within α-CD, and systematic solubility assessments via Job’s continuous variation and the Benesi-Hildebrand method revealed a 1:1 host-guest stoichiometry. The ICs obtained were evaluated for BCNU release in vitro at pH levels of 4, 5, 6.5, and 7.4. The mechanism of BCNU drug release was determined to be Fickian diffusion, with the highest cumulative release noted in the acidic microenvironment. These findings collectively validate the effectiveness of α-CD as a functional excipient for the modulation of BCNU’s physicochemical properties through non-covalent complexation. This strategy shows potential for increasing the stability and solubility of BCNU, which may enhance its therapeutic effectiveness in the treatment of brain tumors. Full article

The coordination chemistry of a hydrazinylpyrazine-derived Schiff base ligand (L1), formed in situ from salicylaldehyde and 2-hydrazinopyrazine, with Fe(III) salts has been systematically investigated under varied synthetic conditions. Six discrete Fe(III) complexes (1a–1e and 2) were isolated and structurally characterised via single-crystal X-ray diffraction, revealing diverse coordination geometries ranging from five-coordinate pseudo-trigonal bipyramidal to six-coordinate pseudo-octahedral environments. The supramolecular architectures are governed by a rich interplay of non-covalent interactions, including hydrogen bonding, halogen bonding, and π–π stacking, which significantly influence the crystallisation pathways and final solid-state structures. Continuous shape measure (CShM) analysis highlights substantial geometric distortion in the bis-tridentate complexes, attributed to the steric and electronic constraints imposed by the ligand. Powder X-ray diffraction and infrared spectroscopy confirm the presence of multiple phases in bulk samples, underscoring the kinetic competition between crystallisation and coordination. The results demonstrate that supramolecular stabilisation of monoligated species can kinetically inhibit bis-ligation, with ligand excess and solvent polarity serving as key parameters to direct complex speciation. These findings provide insight into the delicate balance between coordination geometry, ligand strain, and supramolecular assembly in Fe(III) Schiff base complexes. Full article

The WHO considers the Epidermal Growth Factor Receptor (EGFR) one of the key biomarkers of glioblastoma (GB). EGFR can be identified and targeted using molecular recognition elements (MoREs), like aptamers and aptamer–drug conjugates (ApDCs). Understanding the kinetics of anti-EGFR ApDC interactions with EGFR as well as the kinetics of their internalization into the cells is a crucial step for the further development of anti-EGFR ApDCs. For the first time, a novel approach was implemented to study real-time kinetics by measuring the cellular index (CI) using impedance (xCELLigence). Doxorubicin (DOX) was used as an indicator drug. Because DOX intercalates into the DNA double helix, aptamer–DOX non-covalent complexes were obtained. For the anti-EGFR DNA aptamer GR20, an additional duplex was constructed by synthesizing the extra region (GR20h) and via hybridization with the complementary oligonucleotide (h’) to form a duplex (hh’), thus creating the aptamer construct with complementary oligonucleotide (ACCO) GR20hh’. The original HPLC method quantified the assembly efficiency of an ACCO. The ACCO GR20hh’ retained affinity for the recombinant extracellular domain of EGFR, as measured using Biolayer Interferometry (BLI). According to cytofluorimetry, the ACCO GR20hh’ interacts with cells of continuous culture from GB patient (CCGBP) surgical samples. The DOX–ACCO GR20hh’ complexes are more efficiently internalized by EGFR+ cells lines A-431 and CCGBP 107 than DOX alone. Full article

This study aims to address the poor extensibility, brittleness, and limited hydration stability of pure sodium alginate (SA) hydrogels, which hinder their use in flexible, skin-adherent applications such as facial masks, by developing bio-based composites incorporating five representative functional additives: xanthan gum, guar gum, hydroxyethyl cellulose (HEC), poly(ethylene glycol)-240/hexamethylene diisocyanate copolymer bis-decyl tetradeceth-20 ether (GT-700), and Laponite^® XLG. Composite hydrogels were prepared by blending 1.5 wt% SA with 0.3 wt% of each additive in aqueous humectant solution, followed by ionic crosslinking using 3% (w/w) CaCl₂ solution. Physicochemical characterization included rotational viscometry, uniaxial tensile testing, ATR-FTIR spectroscopy, swelling ratio analysis, and pH measurement. Among them, the SA/XLG composite exhibited the most favorable performance, showing the highest viscosity, shear-thickening behavior, and markedly enhanced extensibility with an elongation at break of 14.8% (compared to 2.5% for neat SA). It also demonstrated a mean swelling ratio of 0.24 g/g and complete dissolution in water within one year. ATR-FTIR confirmed distinct non-covalent interactions between SA and XLG without covalent modification. The hydrogel also demonstrated excellent conformability to complex 3D surfaces, consistent hydration retention under centrifugal stress (+23.6% mass gain), and complete biodegradability in aqueous environments. Although its moderately alkaline pH (8.96) may require buffering for dermatological compatibility, its mechanical resilience and environmental responsiveness support its application as a sustainable, single-use skin-contact material. Notably, the SA/XLG composite hydrogel demonstrated compatibility with personalized fabrication strategies integrating 3D scanning and additive manufacturing, wherein facial topography is digitized and transformed into anatomically matched molds—highlighting its potential for customized cosmetic and biomedical applications. Full article

Europium mononuclear complexes are able to form organic molecular crystals by aggregation of molecules through non-covalent bonding interactions. These crystals have many unique optical properties. However, this kind of crystal still faces some difficulties and challenges in the process of research and application, such as the high difficulty of synthesis and purification, and the difficulty of spectral property modulation. In this work, an europium-containing rare-earth molecular crystal material [Eu(BA)₄(pip)], was prepared via a solvothermal method. It is characterized by low melting point, low polarity, stable structure, high luminescence intensity, and has the potential for the preparation of quantum optical devices. After that, optimized the structure of the molecular crystals by petroleum ether solvent. Through the recrystallization process, a uniform and continuous film was formed, which resulted with a more regular surface morphology, and the changes in the optimized crystal structure had an effect on the europium ion electron-leap energy level, the fluorescence emission spectra also showed higher fluorescence resolving ratio. This study particular emphasis on enhancing the quality of [Eu(BA)₄(pip)] molecular crystals and investigating their impact on their spectral properties. Full article

Carbon dioxide is naturally present in the Earth’s atmosphere and plays a role in regulating and balancing the planet’s temperature. However, due to various human activities, the amount of carbon dioxide is increasing beyond safe limits, disrupting the Earth’s natural temperature regulation system. Today, CO₂ is the most prevalent greenhouse gas; as its concentration rises, significant climate change occurs. Therefore, there is a need to utilize anthropogenically released carbon dioxide in valuable fuels, such as formic acid (HCOOH). Single-atom catalysts are widely used, where a single metal atom is anchored on a surface to catalyze chemical reactions. In this study, we investigated the potential of Cu@Phosphorene as a single-atom catalyst (SAC) for CO₂ reduction using quantum chemical calculations. All computations for Cu@Phosphorene were performed using density functional theory (DFT). Mechanistic studies were conducted for both bimolecular and termolecular pathways. The bimolecular mechanism involves one CO₂ and one H₂ molecule adsorbing on the surface, while the termolecular mechanism involves two CO₂ molecules adsorbing first, followed by H₂. Results indicate that the termolecular mechanism is preferred for formic acid formation due to its lower activation energy. Further analysis included charge transfer assessment via NBO, and interactions between the substrate, phosphorene, and the Cu atom were confirmed using quantum theory of atoms in molecules (QTAIM) and non-covalent interactions (NCI) analysis. Ab initio molecular dynamics (AIMD) calculations examined the temperature stability of the catalytic complex. Overall, Cu@Phosphorene appears to be an effective catalyst for converting CO₂ to formic acid and remains stable at higher temperatures, supporting efforts to mitigate climate change. Full article

Rice bran protein (RBP) is an important plant protein, but its functional properties are reduced due to the presence of disulfide bonds in the structure. Polyphenol modification is an effective strategy to improve protein functional properties. However, the interactions between quercetin (Que) and RBP have not been well-studied. In this study, we explored the mechanism of non-covalent interactions between RBP and Que and systematically evaluated the improvement of functional properties of the RBP–Que complex. The results revealed that the addition of Que can significantly affect the particle size, ζ-potential and protein flexibility of the RBP–Que complex, and the non-covalent interactions significantly altered the secondary structure (α-helix content decreased to 20.28%, β-sheet decreased to 22.02%, β-turn increased to 29.30% and random coil increased to 28.40%) and the tertiary conformation of RBP. Spectroscopic data showed that static quenching occurred. Thermodynamic parameters showed that ΔG, ΔH, and ΔS were negative, revealing that the binding process was spontaneous and exothermic and the main reactive bonds were the hydrogen bond and the van der Waals force. When the Que concentration was 120 μmol/g, the emulsifying and foaming properties were improved by 57.72% and 71.88% compared with the RBP, respectively. The study will expand the application of RBP in the food and beverage processing industry. Full article

With the recent development of accurate protein structure prediction tools, virtually all protein sequences now have an experimental or a modeled structure. It has therefore become essential to develop fast algorithms capable of detecting non-covalent interactions not only within proteins but also in protein-protein, protein-DNA, protein-RNA, and protein-ligand complexes. Interactions involving aromatic compounds, particularly their $\pi$ molecular orbitals, hold unique significance among molecular interactions due to the electron delocalization, which is known to play a key role in processes such as protein aggregation. In this paper, we present PInteract, an algorithm that detects $\pi$-involving interactions in input structures based on geometric criteria, including $\pi$-$\pi$, cation-$\pi$, amino-$\pi$, His-$\pi$, and sulfur-$\pi$ interactions. In addition, it is capable of detecting chains and clusters of $\pi$ interactions as well as particular recurrent motifs at protein-DNA and protein-RNA interfaces, called stair motifs, consisting of a particular combination of $\pi$-$\pi$ stacking, cation/amino/His-$\pi$ and H-bond interactions. Full article

In some cases, the catalytic processes involve the formation of self-organized supramolecular structures due to H-bonds and other non-covalent interactions. It has been suggested that the construction of self-assembled catalytic systems is a promising strategy to mimic enzyme catalysis at the model level. As a rule, the real catalysts are not the primary catalytic complexes, but rather, those that are formed during the catalytic process. In our earlier works, we have established that the effective catalysts M(II)_xL¹_y(L¹_ox)_z(L²)_n(H₂O)_m (M = Ni, Fe, L¹ = acac⁻, L² = activating electron-donating ligand) for the selective oxidation of ethylbenzene to α-phenyl ethyl hydroperoxide are the result of the transformation of primary (Ni(Fe)L¹)_x(L²)_y complexes during the oxidation of ethylbenzene. In addition, the mechanism of the transformation to active complexes is similar to the mechanism of action of NiFeARD (NiFe-acireductone dioxygenase). Based on kinetic and spectrophotometric data, we hypothesized that the high stability of effective catalytically active complexes may be associated with the formation of stable supramolecular structures due to intermolecular hydrogen bonds and possibly other non-covalent bonds. We confirmed this assumption using AFM. In this work, using AFM, we studied the possibility of forming supramolecular structures based on iron complexes with L²-crown ethers and quaternary ammonium salts, which are catalysts for the oxidation of ethylbenzene and are models of FeARD (Fe-acireductone dioxygenase). The formation of supramolecular structures based on complexes of natural Hemin with PhOH and L-histidine or Hemin with L-tyrosine and L-histidine, which are models of heme-dependent tyrosine hydroxylase and cytochrome P450-dependent monooxygenases (AFM method), may indicate the importance of outer-sphere regulatory interactions with the participation of Tyrosine and Histidine in the mechanism of action of these enzymes. Full article

Traditional petroleum engineering materials have problems such as single functionality and poor environmental adaptability in terms of lost circulation control and enhanced oil recovery. Supramolecular gels, with their dynamic reversible non-covalent network structure, demonstrate unique advantages in this regard. This paper classifies supramolecular gels into hydrogen bond type, metal coordination type, host–guest type, and electrostatic interaction type based on differences in crosslinking structures. It explains the construction principles and characteristics of each type of gel and analyses their application progress in petroleum engineering fields, such as lost circulation control in drilling, temporary plugging in fracturing, and profile control in enhanced oil recovery. It also discusses the advantages and disadvantages of different systems and future development directions. Research has shown that the molecular design strategy of supramolecular gels can effectively address technical challenges under complex conditions, offering new insights for oil and gas field development. Further optimization of their long-term stability and large-scale production technology is needed to advance their practical application. Full article

The escalating crisis of multidrug resistance, together with the persistence of antibiotic residues in clinical and environmental matrices, demands integrated strategies that couple sensitive detection, efficient decontamination, and controlled delivery. However, current techniques for quantifying avibactam (AVI)—a broad-spectrum β-lactamase inhibitor—such as HPLC-UV lack the sensitivity and specificity required for both therapeutic drug monitoring and environmental surveillance. Encapsulation of AVI within cyclodextrins (CDs) may simultaneously enhance its stability, bioavailability, and detectability, while the high binding affinities of CDs position them as molecular traps capable of scavenging residual AVI. In this study, the inclusion complexation of AVI with various CDs was examined through molecular dynamics (MD) simulations, experimental isothermal titration calorimetry (ITC), and non-covalent interaction (NCI) analysis. Stable 1:1 inclusion complexes were observed between AVI and β-cyclodextrin (β-CD), 2,6-dimethyl-β-cyclodextrin (DM-β-CD), and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), with standard Gibbs free energies of binding (ΔG°) of –3.64, –3.24, and –3.11 kcal/mol, respectively. In contrast, γ-cyclodextrin (γ-CD) exhibited significantly weaker binding (ΔG° = –2.25 kcal/mol). DFT-based NCI analysis revealed that cooperative interaction topology and cavity complementarity, rather than the sheer number of localized contacts, govern complex stability. Combined computational and experimental data establish β-CD derivatives as effective supramolecular hosts for AVI, despite an entropic penalty in the DM-β-CD/AVI complex. These CD–AVI affinities support the development of improved analytical methodologies and pharmaceutical formulations, and they also open avenues for decontamination strategies based on molecular trapping of AVI. Full article

Today, cathinone and its synthetic derivatives are among the most popular narcotics in the world. Their different cytotoxic activities on humans are increasingly and rapidly being published in forensic reports and the scientific literature. New studies demonstrate that these compounds target the apoptosis of some human cancer cell lines. These results could potentially open a new perspective for cathinones’ use as potential therapeutic agents. Even so, the psychostimulant effects of these compounds require testing their activity in the form of drug delivery systems. In our work, we report on the first theoretical studies concerning the potential use of functionalised carbon nanotubes (CNTs) as carriers in the targeted transport of cathinones. Using density functional theory (DFT), we predicted cathinone–CNT interaction energies in environments with different polarity, as well as the stability of complexes in simplified models of healthy and cancer tissue. The results of the current work provide first-step insights into cathinone–CNT non-covalent complex formation in neutral and acidified environments. This study may serve as the theoretical basis for further experimental works on the possibility of using cathinone–CNT complexes in targeted anticancer therapy. Full article

Polysaccharides and phenols are commonly co-localized in various plant-derived foods, including highland barley (Hordeum vulgare L. var. nudum Hook. f.). The interactions between these compounds can influence multiple characteristics of food products, including their physicochemical properties and functional performance, such as bioavailability, stability, and digestibility, which may support promising application of the phenol and polysaccharide complex in health food industry. In this study, two complexes with potential existence in highland barley, such as β-glucan-ferulic acid (GF) and β-glucan-quercetin (GQ), were prepared using the equilibrium dialysis method in vitro. FTIR and SEM results showed that ferulic acid and quercetin formed complexes with β-glucan separately, with covalent and non-covalent bonds and a dense morphological structure. The pH value, reaction temperature, and concentration of phosphate buffer solution (PBS) were confirmed to have an impact on the formation and yield of the complex. Through the test of the response surface, it was found that the optimum conditions for GF and (GQ) preparations were a pH of 6.5 (6), a PBS buffer concentration of 0.08 mol/L (0.3 mol/L), and a temperature of 8 °C (20 °C). Through in vitro assays, GF and GQ were found to possess good antioxidant activity, with a greater scavenging effect of DPPH, ABTS, and hydroxyl radical than the individual phenolic acids and glucans, as well as their physical mixtures. Taking GF as an example, the DPPH radical scavenging capacity ranked as GF (71.74%) > ferulic acid (49.50%) > PGF (44.43%) > β-glucan (43.84%). Similar trends were observed for ABTS radical scavenging (GF: 54.56%; ferulic acid: 44.37%; PGF: 44.95%; β-glucan: 36.42%) and hydroxyl radical elimination (GF: 39.16%; ferulic acid: 33.06%; PGF: 35.51%; β-glucan: 35.47%). In conclusion, the convenient preparation method and excellent antioxidant effect of the phenol–polysaccharide complexes from highland barley provide new opportunities for industrial-scale production, development, and design of healthy food based on these complexes. Full article