Molecules最新文献

DNA and RNA, by focusing on their unique molecular properties, have transcended their role as carriers of genetic information in life and pioneered new application fields such as molecular robotics and molecular computing. However, as these technologies advance, the limitations inherent in natural nucleic acids and their ecosystems are increasingly becoming apparent as barriers to further application. To overcome these constraints, efforts to create artificial nucleic acids using chemical synthesis are underway and are now reaching a new stage of development. This paper proposes a concept of ultimate nucleic acid, "Omega Nucleic Acids (ΩNA)," as a thought experiment. We discuss the specifications required for this molecule, its implementable functions and approaches, and the construction of an ecosystem centered around ΩNA. By working backward from the characteristics of known natural and artificial nucleic acids, while envisioning next-generation artificial systems and applications in extreme environments, we aim to explore new approaches to nucleic acid chemistry and provide guidelines for constructing innovative artificial molecular systems.

In order to further enhance the extraction yield of total flavonoids from Scutellaria baicalensis Georgi, the extraction process was optimized, and its composition and antioxidant activity were also analyzed. Through single-factor and response surface methodology optimization, the optimal extraction process of total flavonoids from S. baicalensis was obtained as follows: 56% ethanol concentration, 40:1 (mL/g) ratio of liquid to solid, 50 °C extraction temperature, and 1 h of extraction time. Under the optimal extraction conditions, the total flavonoid yield reached was 165.40 mg/g, which was 70.16% higher than the blank group and 89.68% higher than previously reported results. The major composition of total flavonoids was analyzed using UHPLC-MS/MS. A total of 60 flavonoid compounds were identified, of which 20 flavonoids had not been reported previously. The in vitro antioxidant activity of the total flavonoids was analyzed by DPPH and ABTs assays. IC₅₀ of the total flavonoids on DPPH and ABTs free radicals were 0.52 μg/mL and 0.66 μg/mL, respectively, which indicated that the total flavonoids of S. baicalensis had a remarkable free radical scavenging ability. This study should provide theoretical and technical support for the industrial production and bioactivity-oriented utilization of flavonoids from S. baicalensis.

Central nervous system (CNS) disorders such as depression severely impair human health. Targeted inhibition of the GluN1-GluN2A receptor is a promising therapeutic strategy, but current drugs often have adverse effects. To develop novel candidate drugs, this study utilized the (S)-ketamine and GluN1-GluN2A receptor complex as a structural template and conducted de novo drug design with the DrugFlow platform. An integrated strategy of molecular docking-based virtual screening combined with high-throughput binding free energy (∆G_binding) calculations from large-scale molecular dynamics (MD) simulations identified three promising antagonists. The ∆G_binding values of these compounds are all below -18.98 kcal/mol, indicating stronger binding affinity than (S)-ketamine, and they demonstrate promising drug-like properties and development potential. 200-ns MD simulations confirmed their stable receptor binding and mechanism consistent with (S)-ketamine. Electrophysiological recordings revealed that, at a concentration of 10 μM, Compounds A1, A2, and A3 produced concentration-dependent inhibition of GluN1-GluN2A receptor-mediated currents, with fractional inhibition values of 24.26%, 35.36%, and 41.76%, respectively. These findings demonstrate the compounds' potential as CNS disorder therapeutics, requiring further experiments to validate efficacy and advance development for conditions like depression.

Chromium (Cr) exists in multiple oxidation states, with Cr(III) and Cr(VI) being the most environmentally and industrially relevant due to their distinct toxicity profiles and chemical behaviour. This study presents a comprehensive method that combines chemical simulation modelling, emission spectroscopy for quantification, and the controlled laboratory production of Cr species. Key findings include that acid digestion effectively extracted the Cr(III) and total Cr species, while thermodynamic modelling forecasted their stability and speciation under various environmental conditions. Thematic analysis indicates that the current quantification of Cr species is still in early development and remains centralized. Mineralogical and surface investigations showed that samples 1 and 2 have a BET surface area below 1 m²/g, whereas samples 3 and 4 exceed this. All samples are crystalline, with approximately 54.3 weight percent Cr₂O₃, 7.3 weight percent SiO₂, 17.75 weight percent of MgO, and 8.3 weight percent Al₂O₃, suggesting Al and Fe²⁺ replacement of Cr in the spinel structure. Computational fluid dynamics (CFD) modelling revealed that longer residence times are necessary for higher Cr metallization under H₂-CH₄-reducing conditions, and accurately predicted carbon deposition on pellets. These results demonstrate that CFD can optimize the H₂:CH₄ ratio to minimize carbon deposition and enhance gas transport to reaction sites.

Background: Serum-free culture of red blood cells (RBCs) typically leads to rapid loss of viability, limiting experimental and translational applications. Lipid-rich formulations and essential oils may provide biocompatible support for RBC integrity while limiting microbial overgrowth.

Methods: RBCs from nine healthy adult donors were cultured in serum-free RPMI under four conditions: control, vehicle (olive oil, 1:100 v/v), genuine adenosine triphosphate (ATP)-oil^® (1:100 v/v), and laboratory oil, "mimicking" ATP-oil^®. Cultures were maintained for 18 days. Viability was assessed by light microscopy and trypan blue exclusion; bacterial contamination was qualitatively observed on day 18.

Results: Genuine ATP-oil^® maintained 35-45% RBC viability at day 18, whereas control and vehicle cultures declined rapidly. The mimicking preparation did not reproduce these effects. ATP-oil^® immersion was associated with a qualitative reduction in bacterial contamination versus control, consistent with a dual action on RBC preservation and microbial suppression under serum-free conditions.

Conclusions: Supplementation with ATP-oil^® substantially prolongs RBC survival and limits bacterial overgrowth in vitro, outperforming commonly used serum or plasma supplements on a per-volume basis. These findings suggest potential applications for improving ex vivo handling or storage of blood components and for reducing background contamination in diagnostic microbiology. Further studies with larger cohorts are warranted to reveal underlying mechanisms and to define active constituents in order to standardize production.

DNA nanotechnology offers an unprecedented level of structural programmability for organizing metallic nanoparticles into precisely defined architectures, providing a powerful platform for plasmonic biosensing. In particular, gold and silver nanoparticles assembled on DNA nanostructures enable nanometer-scale control over interparticle distance, orientation, and spatial symmetry, which directly govern collective plasmonic behaviors and optical signal transduction. This review summarizes recent advances in DNA nanostructure-mediated assembly of metal nanoparticles, with an emphasis on design principles and assembly strategies that enable static and dynamic control of nanoparticle organization. Representative examples are discussed to illustrate how well-defined plasmonic assemblies give rise to tunable optical responses, including localized surface plasmon resonance modulation, chiroptical signals, fluorescence enhancement or quenching, and surface-enhanced Raman scattering. The role of structural programmability and stimulus-responsive reconfiguration in translating molecular recognition events into amplified optical outputs is highlighted in the context of biosensing. Finally, current challenges and future perspectives are outlined, focusing on structural robustness, signal reproducibility, and integration toward practical and multiplexed biosensing platforms.

The overuse of antibiotics has accelerated the evolution and mutation of drug-resistant bacteria, creating an urgent need for novel antimicrobial drugs and feed additives. Antimicrobial peptides, with their unique membrane-disrupting mechanism that resists the development of resistance, hold promise as antibiotic alternatives. To overcome the limitations of natural antimicrobial peptides-such as poor stability, susceptibility to protease degradation, and short in vivo half-lives-self-assembling peptide technology has emerged. This approach employs non-covalent interactions to orderly assemble monomeric peptides into stable, structured nanomaterials like nanofibers, nanotubes, and hydrogels. This paper outlines the molecular design principles and smart response mechanisms of antimicrobial peptide nanoassemblies, elucidates their core advantages over monomeric peptides, summarizes their application scenarios in anti-infection fields, and discusses limitations and future directions across various domains. It provides insights for future antimicrobial peptide design.

The Lewis acid (LA)-promoted formal [3 + 2] cycloaddition (32CA) reaction of 2-phenyl-1-tosylaziridine (2PTA) with ketone has been studied within the framework of Molecular Electron Density Theory (MEDT) at the ωB97X-D/6-311G(d,p) computational level in dichloromethane. This formal 32CA reaction proceeds through a stepwise mechanism, involving an initial BF₃ LA-promoted aziridine ring-opening process, followed by a ring-closure process to yield the 1,3-oxazolidine product. The activation enthalpy of the most favorable C2-N1 breaking bond step, ΔH^≠ = 6.42 kcal·mol^-1, is 20.98 kcal·mol^-1 lower than that of the non-catalyzed process, the aziridine ring-opening process being totally C2 regioselective and stereospecific. A topological analysis of the electron localization function (ELF) reveals that the most favorable transition state structure exhibits C2 carbocationic character; in this structure, the C2-N1 single bond has broken, while the C2-O4 single bond has not yet formed. A relative interacting atomic energy (RIAE) analysis of the aziridine ring-opening step reveals that the stabilization of the sulfonamide/LA leaving group and that of the ketone frameworks are the key factors responsible for the reduction in the activation barrier in the presence of LAs. LAs shift the mechanism of the aziridine ring-opening process from S_N2-like in the non-catalyzed reaction to S_N1-like in the LA-promoted process, which occurs with the inversion of the C2 carbon.

Background/Objectives: Indocyanine green (ICG) is an FDA-approved, near-infrared fluorescent dye widely used for tumor imaging. This study aimed to evaluate the photodynamic efficacy and selectivity of ICG as a photosensitizer in photodynamic therapy (PDT) against MCF-7 breast cancer cells in 2D monolayers and 3D collagen-embedded cell cultures that simulate ECM diffusion, and to confirm direct generation of singlet oxygen (¹O₂) as the primary cytotoxic species. Methods: MCF-7 breast adenocarcinoma cells and HMEC normal mammary epithelial cells were cultured in 2D monolayers, with MCF-7 cells additionally grown in 3D collagen type I matrices to mimic tumor environments. Cells were incubated with 50 µM ICG for 30 min, washed, and irradiated with a 780 nm diode laser at 39.8 mW/cm². Cell viability was quantified using the Muse^® Count & Viability assay at multiple time points, while ICG uptake and penetration were assessed via flow cytometry, fluorescence microscopy, and confocal imaging. Direct ¹O₂ production was measured through its characteristic 1270 nm phosphorescence using time-resolved near-infrared spectrometry. Results: ICG-PDT reduced MCF-7 viability to 58.3 ± 7.4% in 2D cultures (41.7% cell kill, p < 0.0001) and 70.2 ± 10.7% in 3D cultures (29.8% cell kill, p = 0.0002). In contrast, normal HMECs maintained 91.0 ± 1.3% viability (only 9% reduction, p = 0.08), resulting in a therapeutic index of approximately 4.6. IC₅₀ values in 2D MCF-7 cultures decreased over time from 51.4 ± 3.0 µM at 24 h to 27.3 ± 3.0 µM at 72 h. ICG uptake was higher in 2D (78%) than in 3D (65%) MCF-7 cultures, with diffusion in 3D collagen exhibiting linear depth-dependent penetration. Notably, the singlet-oxygen phosphorescence signal, though weak and requiring highly sensitive detectors, provided direct evidence of efficient ¹O₂ generation. Conclusions: ICG as a photosensitizer in photodynamic therapy using clinically compatible parameters is highly cytotoxic to MCF-7 breast cancer cells while largely sparing HMECs in 2D cell culture. Direct spectroscopic evidence confirms efficient ¹O₂ generation, which contributes significantly to the cytotoxicity. The reduced efficacy in 3D versus 2D models highlights the importance of penetration barriers also present in solid tumors. These results support further preclinical and clinical investigation of ICG as a dual imaging-and-therapy (theragnostic) agent for selective photodynamic treatment of breast cancer.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer lacking estrogen, progesterone, and HER2 receptors. This characteristic limits the effectiveness of hormonal and targeted therapies, and despite advances in chemotherapy (ChT), radiotherapy (RT), surgery, targeted therapy (TT) and immunotherapy (IT), clinical outcomes remain poor, highlighting an urgent need for new therapeutic strategies. The development of advanced nanotechnology-based strategies has opened new avenues for the diagnosis and therapy of TNBC. This review focuses on photothermal therapy (PTT) combined with nanotechnology-based strategies. PTT constitutes an emerging modality for oncological treatment that leverages light irradiation, mostly in the near-infrared (NIR) spectral region, to induce the localized thermal ablation of malignant tissues. When combined with gold nanoparticles (AuNPs), PTT is significantly potentiated. AuNPs have distinctive optical and physicochemical characteristics, rendering them highly effective as multifunctional nanoplatforms. Upon irradiation, AuNPs act as efficient photothermal agents, inducing localized hyperthermia. This thermal effect disrupts cellular homeostasis and initiates a cascade of cell death pathways, including apoptosis and necrosis, culminating in tumor regression. This review describes the latest therapeutic advances of PTT and AuNPs. As this innovative approach progresses toward clinical application, future studies and trials will be crucial in determining its potential for TNBC management and improving patient outcomes.