ACS Applied Nano Materials最新文献

Developing a fluorescence lateral flow assay (LFA) is of great importance for achieving ultrasensitive, quantitative, and rapid testing of clinical specimens at point-of-care. However, the fluorescent quantum dot (QD) nanobeads currently used in LFA still have drawbacks, such as large particle size, which leads to high background, easy aggregation, and poor fluidity. To address this issue, a promising strategy is to utilize plasmonic energy transfer from gold nanoparticles to QDs to create smaller and brighter fluorescent nanobeads without simply increasing the amount of QDs encapsulated in one nanobead. In this study, we prepared plasmon-enhanced quantum dot nanobeads (PEQNBs) by encapsulating gold nanoparticles and QDs into polymer nanobeads using a versatile emulsion-solvent evaporation method. As low as about 4000 PEQNB nanoparticles were detected using a gel imager, which is 14.6 times less nanoparticles than that of QD nanobeads of a similar size. The PEQNB-based LFA for interleukin-6 detection exhibited a higher fluorescence intensity and lower background signal than QD nanobeads of similar size. Moreover, compared to larger-sized QD nanobeads with an average diameter of 131.1 nm, PEQNB with an average diameter of 78.6 nm-based LFA exhibited similar levels of fluorescence intensity but 1.55-fold lower background signal and 1.44-fold lower detection limits. The detection limit of PEQNB-based LFA for IL-6 detection can be as low as 13.1 pg/mL in human serum samples. This work demonstrated that optimized plasmon-enhanced QD nanobeads can further increase the sensitivity and lower the background signals of ultrasensitive fluorescent LFA for disease diagnosis at point-of-care.

Confining materials within nanoscale volumes alters their physical and chemical properties, with positive consequences for energy storage, conversion, and catalysis. The pore structure and composition of scaffolds are essential variables for optimizing these properties, with carbon-based materials being preferred due to their tunable porous structures and chemical versatility. This study investigates the influence of surface functional groups on the dehydrogenation kinetics of nanoconfined NaAlH₄ using zeolite-templated carbons (ZTCs). We focus on oxygen functional groups commonly present as intrinsic impurities on carbon scaffolds, analyzing three ZTC scaffolds to determine how their concentrations and configurations affect dehydrogenation behavior. Our findings reveal that carbonyl groups enhance charge transfer and destabilize Al–H bonds more effectively than ether or phenol groups. This indicates that the type of oxygen functional group is more critical than the quantity, highlighting the importance of properly tailoring oxygen defects to improve hydrogen storage performance in nanoconfined systems.

Wound healing is a complex process often hindered by factors, including infection, oxidative stress, and inflammation, particularly in chronic wounds. Zinc (Zn) has therapeutic potential due to its antibacterial, antioxidant, and anti-inflammatory properties. Similarly, the amino acid tryptophan (W) plays a crucial role in protein synthesis for tissue repair. Herein, we developed zinc–tryptophan (Zn–W) nanosheet assemblies with enhanced multifunctional properties, demonstrating a versatile biomedical application: antioxidant, antibacterial, antibiofilm, and wound-healing. Detailed characterization studies were performed for the newly synthesized Zn–W nanoassemblies. In vitro assays revealed potent antibacterial and antibiofilm activities against both Gram-negative (Escherichia coli) and Gram-positive bacteria (Bacillus subtilis), while antioxidant assays confirmed significant free radical scavenging ability. In vivo wound models showed that Zn–W treatment markedly accelerated the tissue regeneration. These results highlight Zn–W nanoassemblies as promising therapeutics for managing infected and chronic wounds, combining the benefits of Zn and W while overcoming their individual limitations.

Recently, rapid advancements in nanotechnology and materials science have facilitated the expanding application of antibacterial materials across various domains. This study presented 3D antibacterial graphene composite aerogels fabricated via a hydrothermal process using dopamine-grafted carboxymethyl cellulose (DOPA-CMC), ethylenediamine (EDA), and graphene oxide (GO) with negligible volume shrinkage, followed by decoration with AgNPs. The incorporation of reactants effectively converted GO to reduced graphene, facilitating the self-assembly of the latter into three-dimensional structures without shrinkage, occurring at a low temperature of 90 °C and within a short duration of 12 h, ultimately improving energy efficiency and enhancing safety. Transmission and scanning electron microscopy revealed that AgNPs were synthesized into near-spherical shapes with homogeneous distribution and uniform diameters ranging from 10 to 25 nm, attributed to the 3D graphene aerogel matrix, which enhanced the immobilization and inhibited the aggregation of AgNPs. The antibacterial activity of the DCErGO/AgNPs aerogel was evaluated againstEscherichia coli and Staphylococcus aureus, thereby suggesting that the aerogel exhibited a concentration-dependent antibacterial effect, with the DCErGO/AgNPs-0.5 composite aerogel demonstrating significant antibacterial efficacy due to the efficient dispersion of AgNPs. DCErGO/AgNPs aerogels possess broad application potential in healthcare and water treatment and present sustainable approaches for the functionalization and expanded utilization of graphene-based materials.

Triboelectric nanogenerator (TENG) based on the coupling effect of triboelectrification and electrostatic induction can convert mechanical motions into electric energy. Recent studies have found that metal-organic framework materials are promising triboelectric materials due to their large surface area and excellent tunability. In this study, we incorporated isostructural zeolitic imidazolate frameworks, ZIF-8-X (X = CH₃, Br, Cl), into poly(vinylidene fluoride) (PVDF) electrospun fibers and assembled them in TENG devices to investigate the underlying relationship between functional group electronegativity (via varied imidazolate linkers) and triboelectric output performance. Results show that ZIF-8-Cl/PVDF composite fiber demonstrated the highest average voltage and current output of 312.4 ± 2.0 V and 4.90 ± 0.07 μA, respectively, which are 3.8 and 5.5 times higher than that of the pristine PVDF. The practicality of ZIF-8-X-based TENG was tested for harvesting energy from oscillatory motions to power up LEDs and capacitors. A freestanding mode TENG based on ZIF-8-Cl was also designed to harvest rotational energy without physical contact for wider applications. The working mechanism of ZIF-8-X-based TENG was also revealed through nanoscale-resolved chemical studies, providing valuable insights into the design of MOF materials for improved performance of TENGs.

Triboelectric nanogenerator (TENG) based on the coupling effect of triboelectrification and electrostatic induction can convert mechanical motions into electric energy. Recent studies have found that metal–organic framework materials are promising triboelectric materials due to their large surface area and excellent tunability. In this study, we incorporated isostructural zeolitic imidazolate frameworks, ZIF-8-X (X = CH₃, Br, Cl), into poly(vinylidene fluoride) (PVDF) electrospun fibers and assembled them in TENG devices to investigate the underlying relationship between functional group electronegativity (via varied imidazolate linkers) and triboelectric output performance. Results show that ZIF-8-Cl/PVDF composite fiber demonstrated the highest average voltage and current output of 312.4 ± 2.0 V and 4.90 ± 0.07 μA, respectively, which are 3.8 and 5.5 times higher than that of the pristine PVDF. The practicality of ZIF-8-X-based TENG was tested for harvesting energy from oscillatory motions to power up LEDs and capacitors. A freestanding mode TENG based on ZIF-8-Cl was also designed to harvest rotational energy without physical contact for wider applications. The working mechanism of ZIF-8-X-based TENG was also revealed through nanoscale-resolved chemical studies, providing valuable insights into the design of MOF materials for improved performance of TENGs.

Lung cancer is one of the most common cancers and is the leading cause of cancer death. Recent studies have shown that high potassium ion concentrations in the lung cancer tumor microenvironment (TME) can inhibit antitumor immunity through the induction of tumor-associated macrophages (TAMs) into the M2-like phenotype. Given that crown ethers can specifically bind to potassium ions, we constructed a biomimetic pH-sensitive nanoparticle system that uses a liposome encapsulating crown ether as a core drug and the lung cancer cell membrane was employed as the outer coating (CCM-LP@crown-ether). CCM-LP@crown-ether could remove potassium ions and skew M2 macrophages toward the M1-like phenotype in a pH-dependent manner, which enhanced the ability of macrophages to phagocytose and induce tumor cell apoptosis in vitro. Intravenous injection of CCM-LP@crown-ether targeted and cleared specific potassium ions in the tumor and showed good biosafety. Importantly, CCM-LP@crown-ether increased the M1/M2 ratio, reduced MDSC infiltration, and promoted the function and quantification of CD8+ T cells in the tumor microenvironment after intravenous administration, which restored antitumor immunity and effectively inhibited tumor growth in vivo. Furthermore, CCM-LP@crown-ether achieved an enhanced antitumor effect in vivo when combined with an anti-PD-1 antibody (α-PD-1) and prolonged the survival time of tumor-bearing mice. Overall, CCM-LP@crown-ether demonstrated the potential for clinical applications in lung cancer immunotherapy.

Ultraviolet communication is a promising candidate for applications in short-range military communications, internal safety communication in aerospace, etc. Nevertheless, traditional detectors for deep ultraviolet light frequently necessitate high driving voltages and rely heavily on filters. Nanomaterials are efficient means to develop high-performance photodetectors based on their high surface-to-volume ratio, quantum effect, and high light field confinement ability. Herein, the one-dimensional (1D) porous Ga₂O₃ nanorods are fabricated through a straightforward hydrothermal method. Subsequent to optimizing the crystallinity characteristics of these nanorods, the solar blind ultraviolet photodetector (SBPD) performances are studied in detail, including rising edge, falling edge, responsiveness, and switching ratio. Notably, the device with the highest oxygen defect concentration shows a high photo-to-dark current ratio of 10⁶, a fast response time of 28 ms, a responsivity of ∼0.9 mA/W, and a detectivity of 1.4 × 10⁹ Jones, respectively. Furthermore, by using this detector as the signal receiver and a commercial light-emitting diode (LED) with a peak wavelength of 254 nm as the emitter, a deep ultraviolet optical wireless communication (OWC) system is established, employing on–off-keying (OOK) modulation to transmit ASCII codes at a data rate of 50 bps. The received signal increased with the application of bias voltage, successfully transmitting the message “SEU-2024-2025”. This work highlights the potential of 1D porous ultrawide bandgap semiconductor nanorods in deep-ultraviolet photodetection and optical communications.

Exhaled breath (EB) contains rich molecular information that can provide insights into an individual’s health. Clinically relevant molecular analytes, such as volatile organic compounds (VOCs), are exhaled in the form of gases, aerosols, or droplets. Lung cancer is a chronic disease characterized by dyspnea and respiratory failure and can be associated with formaldehyde. In this study, formaldehyde was considered as a biomarker of lung cancer. Herein, a chemi-resistive formaldehyde gas sensor based on Co₃O₄ nuclei-encapsulated ZnO-based yolk–shell spheres (ZnO-Co₃O₄ YSSs) was fabricated. This sensor could distinguish the EB of healthy individuals from those of patients, people, and the simulated EB of patients. Physical models based on density functional theory (DFT) demonstrate that the adsorption of formaldehyde molecules is critical for the sensor’s sensitivity. Additionally, the formaldehyde concentration in the mixed gases can be predicted, using the Extreme Learning Machine (ELM) and Multi-Layer Perceptron (MLP), showing potential for detecting formaldehyde in complex expiratory components.

Layered double hydroxides (LDHs) represent an important class of battery-type electrode materials for supercapacitors (SCs), but they suffer from serious agglomeration and low electronic conductivity. In this paper, amorphous/crystalline CoS_x/NiCo LDH heterogeneous nanosheet arrays have been constructed via partial sulfurization of zeolitic imidazolate framework-L (ZIF-L) template followed by etching with nickel nitrate. The amorphous CoS_x not only provides rich active sites but also acts as a scaffold for anchoring NiCo LDH, preventing its aggregation. The hollow cavity facilitates charge transport and relieves volume expansion during electrochemical process. Besides, the binder-free configuration reduces contact resistance and “dead volume”. With these merits, CoS_x/NiCo LDH displays a high specific capacitance of 1903.8 F g^–1 at 1 A g^–1 with an excellent rate performance (76.1% at 10 A g^–1). In addition, the two-electrode cell assembled from CoS_x/NiCo LDH and activated carbon (AC) outputs an energy density of up to 54.66 W h kg^–1 corresponding to a power density of 800 W kg^–1 at 1 A g^–1 along with satisfactory cycle life (82% after 10,000 cycles at 10 A g^–1).