ACS Applied Nano Materials最新文献

Caffeic acid (CA) possesses antibacterial, antiviral, and anticancer effects but may be genotoxic after excessive intake. Therefore, it is greatly important to fabricate an efficient electrochemical sensor for CA sensing. Herein, a derivative of β-cyclodextrin (4-PyS-β-CD) was successfully synthesized by using β-cyclodextrin and 4-mercaptopyridine. Its structure was characterized by ¹H NMR. The ternary composite 4-PyS-β-CD/RGO/SG-b was prepared by milling 4-PyS-β-CD, spherical graphite (SG), and reduced graphene oxide (RGO) in a mass ratio of 3:3:1.5. Scanning electron microscopy (SEM) demonstrated that the nanoscale particles of SG, the rod-shaped samples of 4-PyS-β-CD, and the lamellar RGO were dispersed in the ternary composite 4-PyS-β-CD/RGO/SG-b. 4-PyS-β-CD/RGO/SG-b@GCE (GCE = glassy carbon electrode) showed fine electrochemical detection performance for CA with a wide linear range (0.004–35 μM) and a low limit of detection (LOD, 1.17 nM). Satisfactory recoveries of 97.59–100.30% and 97.26–100.21% were achieved for the sensing of CA in caffeic acid tablets and blueberries, respectively, demonstrating its potential practical application. Moreover, the possible sensing mechanism for CA, as well as the multiple synergistic effects among the composites, was also explored.

To enhance safety in industrial processes and prevent dangerous exposures to hazardous gases such as H₂, H₂S, and HCN, early detection and monitoring are essential. Using Density Functional Theory, we investigated the D-MoSe₂ (D-Pt, Ir, and Os) monolayers as sensing materials and analyzed their structures, electronic properties, and gas-sensing behaviors. The absence of imaginary phonon bands confirms the dynamical stability of the substitutionally doped monolayers. Their band gaps decrease as new energy states form, and charges are redistributed, improving the surface for better gas adsorption. The Ir-MoSe₂ monolayer interacts highly with all three gases and yields adsorption energies of −0.59 eV for H₂, −1.17 eV for H₂S, and −1.01 eV for HCN. The substantial charges donated from the gas to the material are 0.094, 0.267, and 0.134 e. Followed by which the Pt-MoSe₂ monolayer also chemically interacts with H₂S and HCN gases with significant charge transfer and adsorption energies. The doped monolayers exhibit profound changes in their sensing and electronic properties, as observed through changes in band structure, density of states, electron density differences, and electron localization function-based interactions. The work function changes for Pt-MoSe₂ indicate selective detection (−0.27 and −0.34 eV), and for the Ir-MoSe₂ monolayer, it shows nearly identical changes (−0.35 and −0.34 eV) for H₂S and HCN gases. The Pt-MoSe₂ monolayer releases HCN gas within 12.79 s at 323 K, enabling reliable, repeatable sensing. Also, the Ir-MoSe₂ monolayer recovers HCN gas in 5.32 s at 400 K. Therefore, the Pt- and Ir-MoSe₂ monolayers are acceptable choices for efficient gas-sensing applications, enabling the rational design of a nanosensor with sensitive and selective detection of targeted hazardous gases.

The integration of chemical and biological catalysts to conduct one-pot reactions is regarded as a powerful approach for enhancing the efficiency of chemical synthesis. Here, through a physical confinement strategy, lipase and Ru nanoparticles were immobilized within a metal–organic framework (MOF) to form a hybrid catalyst, CALB-Ru-UiO-66, which was then prepared for use in cascade reactions in organic solvents. Comprehensive characterization techniques were employed to elucidate the structural evolution, elemental distribution, and chemical states of the material. Initially, furfural was selected as the substrate for the reduction–esterification cascade reaction under mild conditions. This approach avoided the harsh requirements of conventional catalytic systems and suppressed undesired side reactions, such as furan ring opening. The catalytic efficiency of CALB-Ru-UiO-66 was 1.5 times higher than that of a physical mixture of Ru-UiO-66 and free CALB. Additionally, the catalyst demonstrated chiral resolution capability for secondary alcohols. The catalyst also exhibited remarkable stability, retaining over 80% of its initial activity after five consecutive reaction cycles and demonstrated efficient and sustained catalytic performance in a continuous-flow packed-bed reactor. This work provides a strategy for developing highly efficient and stable catalysts for biomass transformation, highlighting the potential of enzyme–metal hybrid systems in this field.

Ischemic stroke, caused by the occlusion of a cerebral artery by a thrombus, remains a major global health concern. While the recombinant tissue plasminogen activator (rtPA) is the only approved pharmacological treatment for thrombolysis, its limited efficacy stresses the pressing need for a more effective treatment. Neutrophil extracellular traps (NETs), derived from activated neutrophils and consisting of DNA (along with various proteins), contribute to thrombus resistance to rtPA-mediated thrombolysis. Additionally, rtPA-induced reperfusion can escalate oxidative stress, leading to cerebral hemorrhage. To address both oxidative stress and rtPA resistance in acute ischemic stroke, we thus propose to combine the antioxidant properties of cerium oxide nanoparticles (CNPs) with the DNase I enzyme targeting NETs’ DNA. For this purpose, CNPs were first coated with aminated polyethylene glycol (PEG) terpolymers to improve their colloidal stability and biodistribution. DNase I was then successfully grafted onto coated CNPs using EDC/sulfo-NHS chemistry. Once coated and functionalized, CNP@PEG-DNase retained its biological activities, effectively degrading both plasmid and fibrillar DNA and maintaining its antioxidant activity. In vitro studies showed that the functionalized CNPs did not impair the viability of brain endothelial cells (bEnd.3) and still reduced the reactive oxygen species (ROS) levels. In conclusion, PEG-coated CNPs functionalized with DNase I may facilitate rtPA-induced thrombolysis by degrading NETs and mitigate reperfusion-induced oxidative stress.

Ti³⁺ and Cu codoped TiO₂ nanophotocatalysts, denoted as Cu-BTTNs, were synthesized via a modified solvothermal method. The phase composition, surface morphology, and microstructure characteristics of the material were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). Their photocatalytic performance was evaluated under simulated visible light irradiation (xenon lamp). Using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model bacteria, Cu-BTTNs (200 μg/mL) inactivated 99.74% of S. aureus and 97.26% of E. coli within 12 min (initial concentration: 1 × 10⁶ CFU/mL). Simultaneously, they degraded 96.83% of Rhodamine B (RhB, 10 mg/L) within 15 min at a catalyst dosage of 1.5 mg/mL. Radical trapping experiments identified photogenerated holes (h⁺), superoxide anions (·O₂^–), and hydroxyl radicals (·OH) as the predominant reactive species responsible for bacterial inactivation and pollutant degradation. These results demonstrate that Cu/Ti³⁺ codoped TiO₂ holds significant potential as a high-performance antibacterial material and an effective catalyst for dye wastewater treatment, providing a theoretical foundation for practical environmental applications.

Neotame is a widely used artificial sweetener in milk beverages. However, excessive intake may pose potential health risks, necessitating the development of reliable detection methods. In this work, carbon dots (CDs) were designed for fluorescence enhancement detection of neotame in milk beverages. The CDs were synthesized via a one-pot solvothermal reaction at 180 °C for 8 h using 2-hydroxy-3-naphthalic acid and phthalaldehyde as precursors in ethanol. The obtained CDs demonstrated excellent storage stability, maintaining their performance for over six months at 12 °C under light-proof and sealed conditions, which exhibited their cost-effectiveness and practical utility. Upon the addition of neotame to a CDs solution diluted with ethanol, a new fluorescence emission peak emerged at 515 nm. Systematic investigation revealed that the fluorescence enhancement is attributed to modification of the surface defect states of the CDs, which leads to an increased radiative transition rate. In milk beverages, the fluorescence intensity at 515 nm showed a good linear response to neotame concentrations ranging from 2 to 100 μM, with a calculated detection limit of 1.55 μM (0.58 mg/L). The proposed method exhibits high specificity and strong anti-interference capability, and its application potential in milk beverages has been verified.

Heavy metal ion contamination requires sensitive and selective detection methods for environmental and health monitoring. This study demonstrates that one-dimensional (1D) zinc oxide (ZnO) nanostructures with a controlled morphology enable highly sensitive photoluminescence-based detection of Cu²⁺ and Fe³⁺ ions. Three distinct ZnO morphologies─nanotetrapods, nanorods, and nanofibers─were synthesized and comprehensively characterized. ZnO nanotetrapods exhibited promising sensing performance, with detection limits of 0.92 μM for Cu²⁺ and 1.4 μM for Fe³⁺, response times of 10.6–10.9 ± 2 min, and adequate selectivity over 12 interfering metal cations. The enhanced performance correlates with nanotetrapods’ structure properties, defect chemistry, and highly negative surface charge (−42.3 mV at pH 7). We propose a sensing mechanism based on electrostatic ion adsorption followed by charge transfer that reduces Cu²⁺ to Cu⁺ and Fe³⁺ to Fe²⁺ on the ZnO surface, causing photoluminescence quenching. These findings establish the structure–property relationships for ZnO-based sensors with detection capabilities well below the WHO drinking water guidelines, demonstrating their strong potential for environmental monitoring applications.

Although nanozymes offer tunable catalytic activity for bioanalysis, conventional monometallic formulations are often constrained by suboptimal efficiency and a lack of environmental adaptability. Herein, thermo-responsive polymer-functionalized bimetallic nanozymes, UiO-66-NH₂-poly(N-isopropylacrylamide-co-2-vinyl-4,4-dimethylazlactone)-bovine serum albumin/cerium–gold nanoparticles (U-PNV-BSA/Ce–AuNPs), were successfully designed for the high-performance colorimetric detection of captopril. Comprehensive characterization (TEM, XPS, EDS, XRD) confirmed the material’s structural integrity. Mechanistically, the nanozymes integrates the synergistic electron transfer of Ce³⁺/Ce⁴⁺ and Au⁰/Au⁺ redox couples with temperature-regulated nanoconfinement induced by the polymer coating. This dual mechanism significantly amplified reactive oxygen species (ROS) generation, resulting in a 100-fold and 13-fold enhancement in peroxidase-like activity compared to monometallic AuNPs and CeNPs nanozymes, respectively. Based on this, a colorimetric sensing platform was constructed, demonstrating a good linear relationship (R² = 0.996) and a low limit of detection (0.18 μM). Furthermore, the method exhibited excellent reliability in mouse serum samples with satisfactory recoveries ranging from 97.2% to 102.1%. This work demonstrates that integrating stimuli-responsive components with synergistic bimetallic catalysts offers a promising strategy for pharmaceutical analysis.

The growth of colloidal ZnSe nanorods with controlled crystallographic orientation and size has attracted much attention for exploring their anisotropic properties and size-dependent properties. Herein, a solution-processed strategy was developed to synthesize ⟨002⟩-oriented wurtzite (w-)ZnSe nanorods by heating zinc carboxylate and selenium (Se) in 1-dodecanethiol and oleylamine. The higher molar ratio of zinc stearate (ZnSt₂) to Se and the longer carbon chain length of zinc carboxylate both led to the growth of w-ZnSe nanorods with smaller diameter and length due to the steric hindrance effect. The ⟨002⟩-oriented w-ZnSe nanorods exhibited diameter-dependent excitonic energies and tunable photoluminescence (PL) emissions.

Water splitting technology enables the generation of green hydrogen, simultaneously offering a route for sustainable brine electrolysis to produce sodium hypochlorite (NaOCl). Herein, we report a multifunctional Ag/Co₃O₄/MXene nanocomposite catalyst active for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) while also facilitating NaOCl production from brine water oxidation. XRD results showed that Ag incorporation reduced the crystallite size of Co₃O₄, and FTIR analysis confirmed the improved hydrophilicity of the Ag/Co₃O₄ catalyst resulting from MXene integration. Strong interfacial interactions between MXene and Ag/Co₃O₄ were established by XPS, leading to oxygen-mediated interfacial bonding and associated charge redistribution, thereby enhancing the catalytic behavior. Electrochemical evaluation demonstrated bifunctional performance, with OER and HER activities comparable to those of RuO₂ and Pt/C benchmark catalysts, respectively. Additionally, the catalyst remained stable during extended OER (25 h) and HER (20 h) testing as well as overall water splitting for 30 h at 100 mA cm^–2. Importantly, the catalyst achieved the highest reported value of electrochemically synthesized NaOCl yield, 12 g L^–1, under optimized conditions, including current density, temperature, electrolysis time, and NaCl concentration (40 mA cm^–2, 20 °C, 3–21 h, and 40 g L^–1, respectively). These results highlight Ag/Co₃O₄/MXene as a versatile electrocatalyst for sustainable energy conversion and chemical production.