Since their original development, aptamers (or nucleic acid oligomers of defined sequence that are capable of high-affinity and high-specificity binding to a target) have been heralded as possible and promising new therapeutic modalities. Increasingly versatile and customizable aptamer selection (SELEX) processes, alongside incorporation of novel synthetic nucleic acid (XNA) chemistries, have played a key role in the development of therapeutically relevant molecules. Nonetheless, despite the significant progress in the last 40 years, clinical applications of aptamers remain a nascent field. This review summarises some of the key developments in the field in the last 40 years, highlighting the progress made in aptamer selection, XNA chemistries and computational analyses. We discuss the intricacies and limitations of the current gold standard in aptamer SELEX and underscore the added complexities of XNA incorporation. Reflecting on the distinction between the antibody and aptamer fields, we advocate how a more mature understanding of this class of molecules could be driving the next generation of applications.
Layered double hydroxides (LDHs) are layered materials of increasing interest for environmental applications due to their tunable chemical composition, structure, and adjustable physicochemical properties. This review presents a critical synthesis of recent advances in LDH-based materials, highlighting the close links between synthesis methods, structural characteristics, and key properties controlling their environmental performance. The main synthesis strategies are discussed in relation to their influence on crystallinity, morphology, specific surface area, metal cation distribution, and the nature of structural defects. Particular attention is paid to the effect of cationic composition, interlayer anions, and structural modifications (doping, exfoliation, composite formation) on adsorption, ion exchange, redox activity, and heterogeneous photocatalysis mechanisms. Environmental applications of LDHs are systematically examined, including the adsorption of inorganic and organic pollutants, the photodegradation of emerging contaminants under UV and visible irradiation, and water treatment. LDH-derived materials, particularly mixed metal oxides and LDH/semiconductor composites, are also discussed due to their improved photocatalytic performance and increased stability. Finally, current challenges and future prospects are addressed, with a particular focus on the recyclability, durability, and scaling up of LDH-based materials for advanced environmental applications.
A rapid, highly efficient and practically viable solid-solid melt reaction (SSMR) protocol has been developed for the synthesis of multi-colour-emissive quinoxaline-based small organic fluorophores (QBSOFs, 3) from readily available o-phenylenediamines (1) and α-bromoketones (2) or arylglyoxals/glyoxylic acids (4) under solvent- and catalyst-free conditions. This environmentally benign methodology features operational simplicity, avoidance of cost-intensive and scale-restrictive techniques such as microwave or ultrasonic irradiation, broad substrate compatibility with excellent functional-group tolerance, and a straightforward work-up affording products in high purity. Notably, the reactions proceed rapidly to deliver excellent to near-quantitative yields (95-99%). The successful gram-scale synthesis of 2-(4-chlorophenyl)quinoxaline (3a) further underscores the economic feasibility and industrial applicability of this approach for large-scale production of 2-arylquinoxalines. The solid-state photophysical properties of the synthesized quinoxaline fluorophores were systematically investigated. The compounds exhibit tunable solid-state emission spanning from purplish blue to the yellow light region, primarily governed by the nature of substituents at the 2-position of the quinoxaline core. Remarkably, compounds 4-(quinoxalin-2-yl)benzonitrile (3g) and 4-(6,7-dimethylquinoxalin-2-yl)benzonitrile (3u) display cold-white and warm-white light emission, respectively. Furthermore, the HOMO and LUMO energy levels are comparable to those of reported hole-transporting materials (HTMs), highlighting the dual luminescent and hole-transporting characteristics of these fluorophores. Consequently, these multi-colour-emissive QBSOFs, with intrinsic hole-transporting characteristics could be suitable for application in organic optoelectronic devices.
A novel series of palladium(ii) coordination complexes of the formula [Pd(CH3C(NAr)CHC(O)CH3)2] (4a-j) were synthesized by the reaction of enaminone ligands (3a-j) with [PdCl2(NCCH3)2] in a molar ratio of 2 : 1 in the presence of t BuOK. The square planar coordination geometry around Pd(ii) of the 4c complex, with electrostatic potential calculations rationalizing the formation of C-H⋯π contacts, leading to chain structures, was confirmed by single-crystal X-ray diffraction. UV-vis spectra, supported by TD-DFT (B3LYP) calculations, indicated that the long-wavelength absorptions arose from intra-ligand charge transfer transitions (π → π*) involving HOMO-LUMO+1 excitations, with Pd(ii) orbitals contributing to the HOMO. Thermogravimetric analysis demonstrated high thermal stability of the series. Biological evaluation revealed notable cytotoxicities of the compounds 4b, 4d, 4h, 4i, and 4j. The compound 4i shows the strongest activity (IC50 = 5.42 µM, MCF-7; 17.20 µM, and HCT-116) and high selectivity toward cancer cells. Molecular docking against oncogenic targets (PIK3CA-E545K, ERBB4-Y1242C, KRAS-G13D, PIK3CA-H1047R, and ATM-A112V) identified meta- and para-substituted analogues (4b, 4c, and 4h) as the most favorable binders, while bulky ortho substituents reduced the affinity due to steric effects. Docking against PIK3CA-E545K produced binding energies that qualitatively paralleled several of the measured MCF-7 selectivity indices, with planar aromatic interactions and hydrophobic contacts defining the structure-activity relationships.
This study is designed to synthesize drug-loaded polymer nanocomposites based on starch and hydroxypropyl methyl cellulose (HPMC) natural polymers reinforced with sepiolite clay mineral by a polymer solution casting procedure. Sepiolite clay is used to ensure the thermal and mechanical properties of the film. Ciprofloxacin is a second generation, broad-spectrum antibacterial drug. It is commercially available in suspension and tablet forms. Polymer-clay interactions are a very useful approach to change the physiochemical and thermal properties of drug-loaded films, with the major takeaway being that optimized composition and dispersion enhance the performance, providing a foundation for the rational design of novel nanocomposites. Various formulations of these nanocomposite films have been developed with the objectives of being antibacterial, renewable, biodegradable and biocompatible. These nanocomposites have diverse applications in the packaging, medical, food and pharmaceutical industries. Thermogravimetric analysis (TGA) confirmed that the weight residues of drug-loaded nanocomposites have higher thermal stabilities than non-drug-loaded composites. Energy dispersive X-ray analysis (EDX) showed the elemental composition of the mixed components. X-ray diffraction (XRD) confirmed the amorphous and crystalline nature of the starch and HPMC. Fourier transform infrared (FTIR) spectroscopy was used to examine the compatibility of the polymers. Scanning electron microscopy (SEM) showed the better adhesion, distribution and dispersion of the drug and clay particles. This approach not only benefits the scientific community by understanding interactions but also catalyzes further research towards efficient, cost-efficient and multifunctional biomedical material development.
High-performance visible-light-driven photocatalysts have emerged as a research hotspot in environmental pollution; however, the photocatalytic degradation mechanisms of Congo red using bismuth semiconductor composites are not fully understood. Herein, BiVO4/ZnIn2S4 was successfully synthesized via a hydrothermal method, and the photocatalytic performance of the composite was assessed by carrying out photocatalysis experiments to decompose Congo red. The phase composition, carrier separation capability, interface electron interactions, and morphological features were characterized by XRD, PL, XPS, and TEM analyses, respectively. The results showed that a Z-scheme heterostructure was successfully constructed between the BiVO4 and ZnIn2S4. Electrons in the conduction band of BiVO4 migrated to the valence band of ZnIn2S4, which effectively enhanced the separation of photogenerated charge carriers and improved the degradation capability. Compared with pure BiVO4, 7% BiVO4/ZnIn2S4 displayed superior photocatalytic capability and could completely remove Congo red (100 mg L-1) in 60 min under visible light. Radical trapping experiments combined with electron paramagnetic resonance characterization revealed that the superoxide anion (˙O2 -) and holes (h+) acted as the key reactive species driving Congo red degradation. In addition, six cycles of experiments were performed to verify that the BiVO4/ZnIn2S4 composite retains its high stability. This study provides a feasible strategy for fabricating effective photocatalysts to treat organic pollutants in wastewater.
[This corrects the article DOI: 10.1039/D5RA07856C.].
Accurate knowledge of thermophysical properties and their molecular structural origins is essential for understanding liquid organization in associating mixtures. In this work, the density and viscosity of propyl ethanoate (PE) + C6-C10 1-alkanol mixtures were measured over the full composition range at several temperatures, and the corresponding excess molar volumes (V E) and viscosity deviations (Δη) were determined. To elucidate the structural origins of this behavior, molecular dynamics (MD) simulations and density functional theory (DFT) calculations were combined with experimental observations. Radial and spatial distribution functions reveal that alcohol-alcohol self-association dominates through directional hydrogen bonding, forming transient hydrogen-bonded clusters with dual-donor/acceptor configurations. In contrast, alcohol-ester hydrogen bonding is highly site-specific, occurring exclusively at the ester carbonyl oxygen with significantly weaker intensity. Atoms-in-molecules (AIM) analysis quantifies this interaction hierarchy: ROH-ROH binding energies strengthen from -8.24 to -11.31 kcal mol-1 with chain length due to cumulative dispersion interactions, while ROH-PE interactions remain invariant at ∼-8.30 kcal mol-1. Void space analysis further demonstrates that the disruption of alcohol hydrogen-bond networks by PE creates expanded free volume, with cavity radii distributions shifting toward larger voids as temperature increases. This structural asymmetry provides a quantitative molecular basis for the observed positive excess molar volumes and negative viscosity deviations, establishing a direct link between hydrogen-bond topology, void distributions, and macroscopic thermophysical behavior in ester-alkanol systems.
A total of 48 compounds, including 6 undescribed triterpenoid saponins, notoginsenosides V1-V6 (1-6), were isolated and identified from the radix of Panax notoginseng. Their structures were elucidated by combining various spectroscopic techniques, such as NMR and MS analyses. Among them, (2S)-1-O-(9Z,12Z-octadecadienoyl)-3-O-β-galactopyranosylglycerol (43) exhibited the strongest anti-inflammatory activity against cyclooxygenase-2. The compounds 7, 14, 15, 16, 28, 29, 30, 39, 43, and 45 promoted the proliferation of human oral mucosa fibroblasts (hOMFs). Additionally, the compounds 1, 8, 9, 14, 35, 43, and 45 promoted the proliferation of human dermal papilla cells (hDPCs). These results revealed the potential daily functional benefits of P. notoginseng, including ameliorating oral ulcer conditions and preventing hair loss.
Metal-organic frameworks (MOFs) provide adaptable platforms for drug delivery and antibacterial applications owing to their adjustable porosity, high surface area, and catalytic characteristics. We present the environmentally friendly, room-temperature synthesis of ZIF-8 nanocomposites, both with and without penicillin G encapsulation. The materials were comprehensively evaluated using XRD, Raman spectroscopy, FT-IR, DRS, SEM, and nitrogen sorption isotherms. Structural investigation verified high crystallinity, preservation of framework integrity upon drug encapsulation, and enabled the formation of hierarchical porosity with interparticle mesopores. SEM images identified nanoscale particles (50-100 nm), whereas DRS spectra showed a blue shift following drug encapsulation, suggesting an interaction between penicillin G and the ZIF-8 framework. The antibacterial assessment against Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) bacteria revealed superior efficacy of penicillin-loaded ZIF-8 (ZIF3), resulting in decreasing CFU counts and lower MIC values relative to free penicillin and chloramphenicol (positive control antibiotic). These findings support the promise of ZIF-8-based nanocomposites as effective antibacterial agents for applications in wound healing, drug delivery, and public health protection.
An immobilized fluorine-doped ZrO2-x thin film photocatalyst was synthesized on glass substrates using the pulsed spray pyrolysis (PSP) technique for the first time. PSP is simple to control, capable of producing homogeneous thin films on a mass-production scale, and easy to use. Firstly, the fluorine-doped ZrO2-x thin film was prepared at an optimum deposition temperature at 400 °C and 30 min spray time, and thoroughly characterized. Its performance was then evaluated for the photocatalytic degradation of the Remazol Red (RR) dye as a model organic water contaminant under solar light. The results revealed that the degradation kinetics of the RR dye were represented by pseudo-first-order, and the apparent rate of degradation increased fourfold, i.e., from 78.7 × 10-5 min-1 for the ZrO2 thin film at 400 °C/30 min to 339 × 10-5 min-1 for the F-doped ZrO2-x thin film at 400 °C/30 min. This is due to the presence of fluorine, which reduces the band gap of ZrO2 and exhibits substantial absorption in the solar spectrum instead of the UV range, in addition to the reduction in the rate of electron-hole pair recombination. The study found that the most important role in the RR dye degradation was played by the oxidizing species order: 1O2 ≈ O2˙- > ˙OH. To sum up, the F-doped ZrO2-x thin film is a promising immobilized photocatalyst for dye removal.
BiBaFeTiO6 was synthesized successfully through a sol-gel method. XRD examinations revealed that the compound exhibited a crystalline cubic double-perovskite structure with the space group Pm3̄m. The morphology and elemental composition were examined using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and elemental mapping. Results revealed that the material had a uniform distribution of elements and the predicted chemical composition. Electrical measurements were conducted in the temperature range of 373-453 K and the frequency range of 0.1 Hz to 1 MHz. The AC conductivity of BiBaFeTiO6 was established using the correlated barrier hopping (CBH) model. Activation energies derived from DC conductivity and modulus spectra were comparable, indicating that both the relaxation process and electrical conduction originated from the same underlying mechanism. Furthermore, a thorough examination of the Nyquist plots showed the sensitivity of the material's electrical properties to changes in temperature and frequency. The sample's semiconducting nature was demonstrated by the resistivity and impedance NTCR (negative temperature coefficient of resistance) properties. The Nyquist plots (-Z″ vs. Z') display the contribution of grains and grain boundaries in the electrical conductivity, confirming the existence of a non-Debye-type relaxation. The non-overlapping small polaron tunneling (NSPT) process in BiBaFeTiO6 is suggested by the value of the exponent "s", which denotes the conduction process described by the Correlated Barrier Hopping (CBH) model. This material's NTCR characteristics, including a good stability factor, thermistor constant, and sensitivity factor, may be beneficial for developing NTC-type thermistors.
Carbon dots have gained considerable research attention owing to their excellent optical properties and environmental compatibility. In this study, a one-step hydrothermal synthesis of carbon dots (CDs) is reported using guava extract as a bio-based source. These as-prepared carbon dots were characterized by spectroscopic techniques including ultraviolet-visible spectroscopy, fluorescence spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). High-resolution transmission electron microscopy (HRTEM) analysis was used to study their structure and particle size. The characterization results revealed that the CDs had strong blue luminescence, a high density of oxygen-containing surface functional groups and an amorphous carbon structure. The UV-vis spectrum exhibited typical absorption peaks referred to as π-π* and n-π* transitions, and the fluorescence spectrum indicated the presence of excitation-dependent emission and optimal luminescence in the blue region. The presence of surface groups like hydroxyl, carboxyl and ether groups, as confirmed by FTIR analysis, imparts good hydrophilicity to the luminescent carbon dots. The synthesized carbon dots demonstrated excellent fluorescence-based sensing behavior, showing significant quenching in the presence of hydrazine and enhancement in luminescence upon ethanol exposure. The observed sensing behavior is attributed to the electron transfer interactions between the surface groups of the CDs and analytes.
Nitrogen-containing heterocycles (N-Hets) are among the most prevalent and versatile structural motifs in pharmaceuticals, serving as key scaffolds in over 85% of biologically active small molecules. Their structural diversity and functional versatility have made them integral components of both U.S. Food and Drug Administration (FDA) approved and investigational drug molecules, modulating biological activity across a range of molecular targets. In 2025, the FDA approved 26 small-molecule drugs featuring N-Het frameworks, spanning multiple therapeutic areas, including oncology, metabolic disorders, infectious diseases, and rare/orphan conditions. This review offers a comprehensive overview of these newly approved compounds, emphasizing their biological activity and synthetic approaches. Special attention is given to drug-target interactions, focusing on receptor binding and highlighting the important role of N-Hets in medicinal chemistry. By exploiting the intrinsic chemical properties of N-Hets and leveraging modern synthetic methodologies, these scaffolds continue to drive the discovery of therapeutically relevant molecules, highlighting their sustained significance in modern drug discovery.
Dopamine (DA), a critical biomarker closely associated with the onset and progression of neurological disorders, was sensitively quantified using dual enzyme-mimetic NiMn2O4 nanoflowers. The nanozyme simultaneously exhibits peroxidase- and oxidase-like activities, catalyzing a highly selective cyclization reaction between DA and 1, 3-dihydroxynaphthalene (DHNP). As the DA concentration increased, the intrinsic fluorescence of DHNP at 440 nm was progressively quenched, accompanied by the formation of a new optically active fluorophore with emission at 485 nm and a corresponding absorbance at 455 nm. This dual-mode ratiometric fluorescence-colorimetric sensing strategy enabled self-calibrated detection, effectively minimizing signal fluctuation and matrix interference. The platform displayed excellent linearity over the range of 0-250 µM for fluorescence and absorbance responses, allowing accurate, sensitive, and selective DA determination. Owing to its robustness and reliability, the proposed method is well suited for high-throughput dopamine analysis in diverse biological sample matrices.
As a core fuel material for nuclear reactors, the segregation of non-metallic impurities and the hydrogen embrittlement effect at the grain boundaries of metallic uranium pose a serious threat to the long-term service safety of fuel elements. In this study, density functional theory (DFT) was employed to systematically compare the segregation behaviors of six typical non-metallic atoms (C, N, O, Si, P, and S) at uranium grain boundaries and reveal their synergistic regulatory mechanisms on grain boundary strength and hydrogen embrittlement. The key findings are as follows: all non-metallic elements exhibit an intrinsic tendency to segregate spontaneously at grain boundaries; the closer the site is to the grain boundary core, the stronger the segregation tendency and the more stable the binding state. Non-metallic elements weaken grain boundaries, with Si, P, and S inducing a significantly more pronounced weakening effect than C, N, and O. This difference is primarily attributed to the size-mismatch strain caused by the disparity in atomic radius between non-metallic dopants and the uranium matrix. The dominant mechanism underlying the synergistic grain boundary weakening by hydrogen and non-metallic elements is the chemical contribution: the weak bonds formed between hydrogen and non-metallic atoms replace the original strong non-metal-U bonds, resulting in a significant reduction in electron cloud density at grain boundaries. This study clarifies the non-metallic segregation at uranium grain boundaries and its influence on hydrogen behavior at the atomic scale, providing a key theoretical basis for the design of uranium-based fuels with enhanced resistance to hydrogen embrittlement.
A nanoconfinement approach was employed in this study to encapsulate activated carbon with calcium oxide NPs. Here, we present an innovation in materials science by introducing a CaO@AC bifunctional catalyst with unique crystallographic structure and outstanding properties for wastewater treatment and energy storage. This catalyst enables the fast degradation of cocktail pollutants within a minimum time and is useful for the storage of clean energy. The photocatalytic degradation of rhodamine-B, rose bengal, and methylene blue was successfully performed by the bifunctional catalyst with 95%, 74%, 86% degradation efficiencies, respectively, within 40 min. The bifunctional catalyst showed a low charge transfer resistance, decreasing from 1.81 Ω before charge-discharge cycling to 1.62 Ω after cycling, indicating faster ionic diffusion, higher structural stability, and increased surface activation of the electrode. This catalyst achieved a high specific capacity of 230 F g-1 at 4 A g-1 in 3 M KOH and retained approximately 99% of its initial capacitance after 5000 cycles. Additionally, the doped CaO@AC nanocomposite exhibited an enlarged CV area compared with the AC electrode, indicating an enhanced electron adsorption capacity due to the surface functionalities of the CaO@AC matrix. This work paves the way for the further exploration of the innovative CaO@AC bifunctional catalyst as a promising candidate for sustainable development.
A novel, environmentally sustainable spectrofluorimetric method was developed for the determination of clemastine fumarate in pharmaceutical formulations and biological matrices using nitrogen and phosphorus co-doped carbon quantum dots (N,P-CQDs) as fluorescent nanoprobes. The N,P-CQDs were synthesized via rapid microwave-assisted carbonization of citric acid, urea, and phosphoric acid, yielding uniform nanoparticles (3.2 ± 0.9 nm) with high quantum yield (47.2 ± 2.3%) and strong blue emission at 445 nm. Face-centered central composite design was employed to optimize analytical parameters, achieving optimal conditions at pH 8.7, a buffer volume of 1.5 mL, an N,P-CQD concentration of 175 µg mL-1, and an incubation time of 3 minutes. Mechanistic studies confirmed static fluorescence quenching through ground-state complex formation driven by electrostatic interactions between protonated clemastine and deprotonated carboxyl groups on the nanoprobe surface. The validated method exhibited excellent linearity (0.1-4.0 µg mL-1, r 2 = 0.9997), high sensitivity (LOD = 0.03 µg mL-1), satisfactory accuracy (100.41 ± 1.12%), and high precision (RSD < 2%). Successful application in synthetic pharmaceutical tablets and spiked human plasma samples demonstrated practical applicability, with statistical equivalence to reported HPLC methods. Comprehensive green chemistry assessment using MOGAPI (76), CaFRI (78), BAGI (72.5), and RGB12 (whiteness = 84.3) confirmed outstanding environmental sustainability and balanced analytical performance. The proposed method offers a rapid, cost-effective, and environmentally friendly alternative to conventional chromatographic techniques for clemastine quality control and bioanalytical applications.
High-density lipoprotein (HDL) carries proteins and glycoproteins involved in lipid metabolism and inflammatory regulation, yet quantitative characterization of HDL-associated peptides in Alzheimer's disease (AD) cohorts remains challenging due to small biological effect sizes superimposed on substantial technical variability. We applied a Locally Estimated Scatterplot Smoothing (LOESS)-based drift correction and internal-standard-guided normalization workflow to targeted multiple reaction monitoring (MRM) glycoproteomic data generated from HDL isolates collected from 194 participants spanning the cognitive spectrum. Of the 164 transitions originally targeted, 59 features passed quality control (QC), and 21 HDL-associated peptide and glycopeptide features showed consistent signal across all 194 samples; these 21 analytes were used for analysis. Normalization improved analytical reproducibility, reducing median HDL pooled QC coefficients of variation from 69.1% to 55.2%. APOE genotype analyses identified six peptides with statistically significant differences between APOE3/E3 and APOE3/E4 carriers, five of which remained statistically significant after false-discovery rate correction, and all six of which remained significant in covariate-adjusted models, whereas disease-related differences within APOE3/E3 carriers were modest and did not remain statistically significant after covariate adjustment. These findings demonstrate that LOESS-based drift correction combined with feature-specific internal-standard selection stabilizes quantitative HDL glycoproteomic measurements and support downstream comparisons. This workflow provides a practical framework for QC-informed normalization in targeted glycoproteomics and highlights APOE-associated variation in HDL peptides within an aging clinical cohort.
In this research, a novel method for synthesizing various heterocyclic derivatives via the Minisci radical substitution reaction has been presented. The Minisci reaction offers a very efficient and valuable approach for directly functionalizing heteroarenes with an electron-deficient group, allowing the formation of carbon-carbon bonds straightforwardly and efficiently. We have developed a metal-free, light-independent Minisci-type strategy for the direct C-H functionalization of pyrimidines, thereby facilitating the design of heteroaromatic derivatives containing hydrazone groups. The target derivatives were successfully synthesized in good yields using aromatic aldehydes as alkyl radical precursors. The reaction proceeds through a sequence of hydrogen atom abstraction (HAA) from the aldehyde, followed by decarbonylation under oxidative conditions using K2S2O8 and trifluoroacetic acid (TFA). This method provides a practical and scalable approach to accessing structurally heterocyclic compounds of various classes.