Search Results (207)

We report a rapid aqueous method for synthesizing monodisperse gold nanoparticles (AuNPs), employing 2-propynylamine as both an intrinsic reducing agent and a surface-stabilizing ligand. This self-mediated process—achieved in a single step—yields spherical AuNPs with an average diameter of 4.0 ± 1.0 nm and a well-defined localized surface plasmon resonance band centered at 520 nm. Acting as a bifunctional molecule, 2-propynylamine simultaneously reduces HAuCl₄·3H₂O to elemental gold and passivates the nanoparticle surface through coordination via the amine group, while preserving a terminal alkyne (–C≡CH) functionality. This reactive moiety remains exposed and chemically accessible, enabling post-synthetic modification through Cu(I)-catalyzed azide–alkyne cycloaddition. Control experiments using alternate milling times and vial composition confirmed the essential role of 2-propynylamine in mediating both reduction and surface functionalization. The resulting alkyne-functionalized AuNPs serve as versatile “click-ready” platforms for bioconjugation, sensing, and advanced material assembly. Overall, this scalable, green approach eliminates the need for external reducing or capping agents and provides a modular route to chemically addressable nanomaterials with tunable surface reactivity. Full article

In malignant-type gastric cancer, peritoneal dissemination is the most frequent metastatic process and is an inoperable condition for which effective treatment is lacking. Our research has revealed that galectin-4 plays an important role in the peritoneal metastasis of gastric cancer cells. Based on this, we hypothesized that inhibiting galectin-4 could suppress peritoneal metastasis. The inhibitory activity towards galectin-4 binding was evaluated using an enzyme-linked immunosorbent assay, while the suppressive effect on gastric cancer cell proliferation was assessed using an adenosine triphosphate-based cell viability assay. Direct binding to galectin-4 was examined by surface plasmon resonance analysis. Chemically synthesized fucoidan analogs exhibited significant suppressive activity against the proliferation of gastric cancer cells, partly via a galectin-4-mediated pathway. Among the 13 fucoidan analogs tested, analog 10, whose sugar chains composed of repeating 2,3-O-sulfated α(1,4)-linked L-fucose, showed significant inhibitory activity against galectin-4 binding and cell proliferation. 14, the cholestanol-conjugated analog 10, exhibited a pronounced increase in inhibitory activity, consistent with potential multimerization. Molecular docking and site-directed mutagenesis studies revealed that Arginine-45 in galectin-4 is important for binding to fucoidan analogs. In conclusion, fucoidan analogs with a strong affinity for galectin-4 are promising candidates for inhibiting the peritoneal metastasis of galectin-4-positive gastric cancer cells. Full article

Cell membranes and the cytoskeleton play crucial roles in the regulation of cellular responses by mediating mechanical forces and physical stimuli from the microenvironment through their viscoelastic properties. Investigating these properties provides valuable insights into disease mechanisms and therapeutic strategies. Gold nanorods (GNRs), especially under irradiation, exhibit lethal effects against Leishmania parasites through plasmonic photothermal conversion. In this study, we focus on evaluating the effects of non-irradiated GNRs on macrophage properties to better understand their intrinsic interactions with cells and support the development of future phototherapy applications. Here, defocusing microscopy (DM), a quantitative phase microscopy technique, was used to analyze membrane fluctuations in macrophages ($M\varnothing s$) exposed to GNRs (average length of $43\pm 8 \mathrm{n}\mathrm{m}$ and diameter of $20\pm 4 \mathrm{n}\mathrm{m}$) and infected with Leishmania amazonensis. By quantifying membrane–cytoskeleton fluctuation from defocused images, we extracted viscoelastic parameters, including bending modulus ($k_c$) and viscosity ($\eta$), to characterize membrane behavior in detail. Our results show that infection increases both $k_c$ and $\eta$, while treatment at IC₅₀ reduces infection and selectively increases $k_c$ without affecting $\eta$. In healthy macrophages, exposure to GNRs resulted in a reduction in both parameters, indicative of increased membrane fluidity and cytoskeletal rearrangement. These findings provide new insights into the biomechanical effects of GNRs on macrophages and may enlighten the design of future phototherapeutic approaches. Full article

The design of photocatalysts capable of generating localized surface plasmon resonance (LSPR) effects represents a promising strategy for enhancing photocatalytic activity. However, the mechanistic role of plasmonic nanoparticles-induced interfacial electric fields in driving photocatalytic processes remains poorly understood. To produce a Schottky junction, varying amounts of Au nanoparticles widely utilized to broaden the light absorption were loaded onto ultrathin carbon nitride sheets (Au/UCN). The Au/UCN-20 Schottky junction exhibits exceptional photocatalytic activity, achieving a hydrogen evolution rate (14.2 mmol·g⁻¹ over a 4 h period) while maintaining robust stability through five consecutive photocatalytic cycles. The LSPR activity of Au nanoparticles are responsible for the broadened light absorption spectrum of Au/UCN nanocomposites. The interfacial electric field generated at the Au /UCN heterojunction is proposed to enhance charge-transfer efficiency through Schottky barrier penetration of photocarriers, mediated by electric field-driven carrier migration, according to surface potential and finite-difference time-domain (FDTD). These findings uncover a previously obscured photocatalytic mechanism driven by LSPR-induced interfacial electric fields, pioneering a quantum-dot-directed strategy to precisely engineer charge dynamics in advanced photocatalysts via targeted manipulation of nanoscale electric field effects. Full article

Objective: The development of natural and new P-gp modulators to reverse tumor multidrug resistance (MDR). Methods: Test compounds were prepared from the plant Metaplexis japonica, and their ability to reverse P-glycoprotein (P-gp)-mediated MDR was investigated in HepG2/Dox cells. Their effects on P-gp expression and function and their interaction modes with P-gp were also investigated. Results: Natural product 3β,12β,14β, 17β,20(S)-pentahydroxy-5α-pregnan-12β-O-(E)-cinnamate (1) and its new semisynthetic derivative 3β12β,14β,17β,20(S)-pentahydroxy-5α-pregnan-3β-O-nicotinate-12β-O-(E)-cinnamate (1a) were obtained. At non-cytotoxic concentrations of 5 or 10 μM, they significantly reversed the resistance of HepG2/Dox cells to P-gp substrate drugs doxorubicin, paclitaxel, and vinblastine, with reversal folds of 7.1, 118.5, and 198.3 (1), and 18.8, 335.8, and 140.0 (1a), respectively, at 10 μM. Cell apoptosis and expression of caspase 9 were both triggered by the combination of 10 μM of compound 1 or 1a and 500 nM of paclitaxel (p < 0.001). Compound 1 or 1a did not affect P-gp expression, but it did significantly suppress the efflux of Rhodamine 123 out of HepG2/Dox cells (p < 0.001). On the Caco-2 cell monolayer, 1 and 1a were shown to be non-substrates of P-gp, with efflux ratios of 0.83 and 0.89. Molecular docking revealed their strong binding energies (−8.2 and −8.4 kcal/mol) with P-gp, and their direct binding to P-gp was confirmed by their dissociation constants (5.53 µM for 1 and 3.72 µM for 1a), determined using surface plasmon resonance. Conclusions: Compounds 1 and 1a are potential P-gp modulators; they may reverse P-gp-MDR through interacting with P-gp to interfere with substrate binding and transporting, and have the potential to improve the efficacy of paclitaxel or vinblastine drugs for combating P-gp-mediated MDR in tumor cells. Full article

Background/Objectives: The heterogeneity of cancer disease and the frequent ineffectiveness and resistance observed with currently available treatments highlight the importance of developing new antitumor therapies. The properties of gold nanoparticles, such as their photon-energy heating, are attractive for oncology therapy; this can be effective and localized. The combination of chemotherapy and hyperthermia is promising. Our aim was to evaluate the combination therapy of photon hyperthermia with 5-fluorouracil (5-FU) both in vitro and in vivo. Methods: This study evaluated the antitumor efficacy of a combined chemo-photothermal therapy using 5-fluorouracil (5-FU) and branched gold nanoshells (BGNSs) in a colorectal cancer model. BGNSs were synthesized via a seed-mediated method and characterized by electron microscopy and UV–vis spectroscopy, revealing an average diameter of 126.3 nm and a plasmon resonance peak at 800 nm, suitable for near-infrared (NIR) photothermal applications. In vitro assays using SW620-GFP colon cancer cells demonstrated a ≥90% reduction in cell viability after 24 h of combined treatment with 5-FU and BGNS under NIR irradiation. In vivo, xenograft-bearing nude mice received weekly intratumoral administrations of the combined therapy for four weeks. The group treated with 5-FU + BGNS + NIR exhibited a final tumor volume of 0.4 mm³ on day 28, compared to 1010 mm³ in the control group, corresponding to a tumor growth inhibition (TGI) of 100.74% (p < 0.001), which indicates not only complete inhibition of tumor growth but also regression below the initial tumor volume. Thermographic imaging confirmed that localized hyperthermia reached 45 ± 0.5 °C at the tumor site. Results: These findings suggest that the combination of 5-FU and BGNS-mediated hyperthermia may offer a promising strategy for enhancing therapeutic outcomes in patients with colorectal cancer while potentially minimizing systemic toxicity. Conclusions: This study highlights the potential of integrating nanotechnology with conventional chemotherapy for more effective and targeted cancer treatment. Full article

We present a simple method for customizing the optical characteristics of gold-core, silver-shell (Au@Ag) nanoparticles through controlled morphosynthesis via a seed-mediated chemical reduction approach. By systematically adjusting the concentration of cetyltrimethylammonium chloride (CTAC), we obtained precise control over both the thickness of the Ag shell and the particle shape, transitioning from spherical nanoparticles to distinctly defined nanocubes. Bright field and high-angle annular dark-field scanning transmission electron microscopy (BF-STEM and HAADF-STEM), and energy-dispersive X-ray spectroscopy (EDS) were employed to validate the structural and compositional changes. To link morphology with optical behavior, we utilized the Mie and Maxwell–Garnett theoretical models to simulate the dielectric response of the core–shell nanostructures, showing trends that align with experimental UV-visible absorption spectra. This research presents an easy and adjustable method for modifying the plasmonic properties of Ag@Au nanoparticles by varying their shape and shell, offering opportunities for advanced applications in sensing, photonics, and nanophotonics. Full article

Glycyrrhizic acid (GA) and its derivatives have been reported to have potent pharmacological effects against viral infections, including SARS-CoV and SARS-CoV-2. However, their antiviral mechanisms against coronaviruses are not fully understood. In this study, we found that diammonium glycyrrhizinate (DG) can effectively reduce infections of several human coronaviruses, including HCoV-OC43, HCoV-229E, and SARS-CoV-2, as well as newly emerged variants, with EC₅₀ values ranging from 115 to 391 μg/mL being recorded. Time-of-addition and pseudotype virus infection studies indicated that DG treatment dramatically inhibits the process of virus entry into cells. Furthermore, we demonstrated that DG broadly binds to the RBD of human coronaviruses, thereby blocking spike-mediated cellular entry, by using TR-FRET-based receptor-binding domain (RBD)-ACE2 interaction assay, capillary electrophoresis (CE), and surface plasmon resonance (SPR) assay. In support of this notion, studies of molecular docking and amino acid mutation showed that DG may directly bind to a conserved hydrophobic pocket of the RBD of coronaviruses. Importantly, intranasal administration of DG had a significant protective effect against viral infection in a HCoV-OC43 mouse model. Finally, we found that combinations of DG and other coronavirus inhibitors exhibited antiviral synergy. In summary, our studies strongly reveal that DG exerts broad-spectrum antiviral activity against human coronaviruses by interrupting spike-mediated cellular entry, demonstrating the pharmacological feasibility of using DG as a candidate for alternative treatment and prevention of coronavirus infection. Full article

Ag/AgCl-decorated layered lanthanum oxide (La₂O₃) and niobium pentoxide (Nb₂O₅) plasmonic photocatalysts are fabricated through an ionic liquid-mediated co-precipitation method. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) techniques were used to illustrate the physicochemical properties of the materials. The photoactivity was evaluated for the degradation of Acid Blue 92 (AB92) azo dye, a typical organic contaminant from the textile industry, and U251 cancer cell inactivation. According to the results, Nb₂O₅–Ag/AgCl was able to remove >99% of AB92 solution in 35 min with the rate constant of 0.12 min⁻¹, 2.4 times higher than that of La₂O₃–Ag/AgCl. A pH of 3 and a catalyst dosage of 0.02 g were determined as the optimized factors to reach the highest degradation efficiency under solar energy at noon, which was opted to have the highest sunlight intensity over the reactor. Also, 0.02 mg/mL of Nb₂O₅–Ag/AgCl was determined to be of great potential to reduce cancer cell viability by more than 50%, revealed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and mitochondrial membrane potential (MMP) examinations. The mechanism of degradation was also discussed, considering the key role of Ag⁰ nanoparticles in inducing a plasmonic effect and improving the charge separation. This work provides helpful insights to opt for an efficient rare metal oxide with good biocompatibility as support for the plasmonic photocatalysts with the goal of environmental purification under sunlight. Full article

The therapeutic use of silver nanoparticles (AgNPs) has been increasing, especially in phototherapy strategies. The plasmonic properties of AgNPs have contributed to their excellent results as phototherapeutic agents, namely for photodynamic therapy (PDT), photothermal therapy (PTT), and photodynamic inactivation of microorganisms. Moreover, the capacity of these nanostructures to release silver ions (Ag⁺) and enhance the production of reactive oxygen species (ROS) has been explored in combination with light to treat several diseases. Moreover, synthesis, functionalization, and conjugation strategies with targeting agents have been widely studied to optimize selectivity and maximize the therapeutic efficacy of these nanoplatforms. In this work, we reviewed the recent advancements (2019–2024) in the use of AgNPs for phototherapy applications, with an emphasis on evaluating therapeutic efficacy and specific targeting. According to the literature, in oncology, AgNPs have been predominately employed in PTT-based strategies, demonstrating significant tumor cell death and preservation of healthy tissues, in both in vitro and in vivo studies. Concurrently, AgNP-mediated PDT has emerged as a promising approach for the eradication of bacteria and fungi, particularly those commonly associated with antibiotic resistance. The compiled data indicate that AgNPs represent an innovative and effective therapeutic alternative, with a strong potential for clinical translation, in both cancer treatment and the management of hard-to-treat infections. Full article

Two-dimensional transition metal carbides/nitrides (MXenes) have shown potential in biosensors, cancer theranostics, microbiology, electromagnetic interference shielding, photothermal conversion, and thermal energy storage due to their unique electronic structure, ability to absorb a wide range of light, and tunable surface chemistry. In spite of the growing interest in MXenes, there are relatively few studies on their applications in phase-change materials for enhancing thermal conductivity and weak photo-responsiveness between 0 °C and 150 °C. Thus, this study aims to provide a current overview of recent developments, to examine how MXenes are made, and to outline the combined effects of different processes that can convert light into heat. This study illustrates the mechanisms that include enhanced broadband photon harvesting through localized surface plasmon resonance, electron–phonon coupling-mediated nonradiative relaxation, and interlayer phonon transport that optimizes thermal diffusion pathways. This study emphasizes that MXene-engineered 3D thermal networks can greatly improve energy storage and heat conversion, solving important problems with phase-change materials (PCMs), like poor heat conductivity and low responsiveness to light. This study also highlights the real-world issues of making MXene-based materials on a large scale, and suggests future research directions for using them in smart thermal management systems and solar thermal grid technologies. Full article

Surface plasmon resonance (SPR) is a powerful tool for analyzing biomolecular interactions and is widely used in basic biomedical research and drug discovery. Heparan sulfate (HS) is a linear complex polysaccharide and a key component of the extracellular matrix and cell surfaces. HS plays a pivotal role in maintaining cellular functions and tissue homeostasis by interacting with numerous proteins, making it essential for normal physiological processes and disease states. Deciphering the interactome of HS unlocks the mechanisms underlying its biological functions and the potential for novel HS-related therapeutics. This review presents an overview of the recent advances in the application of SPR technology to HS interactome research. We discuss methodological developments, emerging trends, and key findings that illustrate how SPR is expanding our knowledge of HS-mediated molecular interactions. Additionally, we highlight the potential of SPR-based approaches in identifying novel therapeutic targets and developing HS-mimetic drugs, thereby opening new avenues for intervention in HS-related diseases. Full article

An aqueous leaf extract of Egeria densa was used to green-synthesize iron (II) and iron (III) oxide nanoparticles from ferrous sulphate and ferric chloride, respectively. The successful green synthesis of the nanoparticles was confirmed through UV–visible spectroscopy, and the colour of the mixtures changed from light-yellow to green-black and reddish-brown for FeO–NPs and Fe₂O₃–NPs, respectively. The morphological characteristics of the nanoparticles were determined using an X-ray diffractometer (XRD), a Fourier transform infrared spectrophotometer (FTIR), a transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy (EDX). The UV–Vis spectrum of the FeO–NPs showed a sharp peak at 290 nm due to the surface plasmon resonance, while that of the Fe₂O₃–NPs showed a sharp peak at 300 nm. TEM analysis revealed that the FeO–NPs were oval to hexagonal in shape and were clustered together with an average size of 18.49 nm, while the Fe₂O₃-NPs were also oval to hexagonal in shape, but some were irregularly shaped, and they clustered together with an average size of 27.96 nm. EDX analysis showed the presence of elemental iron and oxygen in both types of nanoparticles, indicating that these nanoparticles were essentially present in oxide form. The XRD patterns of both the FeO–NPs and Fe₂O₃–NPs depicted that the nanoparticles produced were crystalline in nature and exhibited the rhombohedral crystal structure of hematite. The FT-IR spectra revealed that phenolic compounds were present on the surface of the nanoparticles and were responsible for reducing the iron salts into FeO–NPs and Fe₂O₃–NPs. Conclusively, this work demonstrated for the first time the ability of Elodea aqueous extract to synthesize iron-based nanoparticles from both iron (II) and iron (III) salts, highlighting its versatility as a green reducing and stabilizing agent. The dual-path synthesis approach provides new insights into the influence of the precursor oxidation state on nanoparticle formation, thereby expanding our understanding of plant-mediated nanoparticle production and offering a sustainable route for the fabrication of diverse iron oxide nanostructures. Furthermore, it provides a simple, cost-effective, and environmentally friendly method for the synthesis of the FeO–NPs and Fe₂O₃–NPs using Egeria densa. Full article

This study pioneers the development of a synergistic Ag-doped molecularly imprinted TiO₂ photocatalyst (MIP-Ag-TiO₂) through a multi-strategy engineering approach, integrating molecular imprinting technology with plasmonic metal modification via a precisely optimized sol–gel protocol. Breaking from conventional non-selective photocatalysts, our material features an engineered surface architecture that combines selective molecular recognition sites with enhanced charge separation capabilities, specifically tailored for the targeted degradation of recalcitrant salicylic acid (SA) contaminants. Advanced characterization (XRD, EPR, FT-IR, TEM-EDS) reveals unprecedented structure–activity relationships, demonstrating how template molecule ratios (Ti:SA = 5:1) and calcination parameters (550 °C) collaboratively optimize both adsorption selectivity and quantum efficiency. The optimized MIP-Ag-TiO₂ achieves breakthrough performance metrics: 98.6% SA degradation efficiency at 1% Ag doping, coupled with a record selectivity coefficient R = 7.128. Mechanistic studies employing radical trapping experiments identify a dual •OH/O_2⁻-mediated degradation pathway enabled by the Ag-TiO₂ Schottky junction. This work establishes a paradigm-shifting “capture-and-destroy” photocatalytic system that simultaneously addresses the critical challenges of selectivity and quantum yield limitations in advanced oxidation processes, positioning molecularly imprinted plasmonic photocatalysts as next-generation smart materials for precision water purification. Full article

Myosin phosphatase (MP) holoenzyme consists of protein phosphatase-1 (PP1) catalytic subunit (PP1c) associated with myosin phosphatase target subunit-1 (MYPT1) and it plays an important role in mediating the phosphorylation of the 20 kDa light chain (MLC20) of myosin, thereby regulating cell contractility. The association of MYPT1 with PP1c increases the phosphatase activity toward myosin; therefore, disrupting/dissociating this interaction may result in inhibition of the dephosphorylation of myosin. In this study, we probed how MYPT1^32–58 peptide including major PP1c interactive regions coupled with biotin and cell-penetrating TAT sequence (biotin-TAT-MYPT1) may influence MP activity. Biotin-TAT-MYPT1 inhibited the activity of MP holoenzyme and affinity chromatography as well as surface plasmon resonance (SPR) binding studies established its stable association with PP1c. Biotin-TAT-MYPT1 competed for binding to PP1c with immobilized GST-MYPT1 in SPR assays and it partially relieved PP1c inhibition by thiophosphorylated (on Thr696 and Thr853) MYPT1. Moreover, biotin-TAT-MYPT1 dissociated PP1c from immunoprecipitated PP1c-MYPT1 complex implying its holoenzyme disrupting ability. Biotin-TAT-MYPT1 penetrated into A7r5 smooth muscle cells localized in the cytoplasm and nucleus and exerted inhibition on MP with a parallel increase in MLC20 phosphorylation. Our results imply that the biotin-TAT-MYPT1 peptide may serve as a specific MP regulatory cell-penetrating peptide as well as possibly being applicable to further development for pharmacological interventions. Full article