ACS Applied Nano Materials最新文献

Graphene-based materials are emerging as promising platforms in nanomedicine due to their high surface area and substantial drug-loading capacities. However, their clinical translation is hindered by challenges related to biocompatibility and the ability to cross physiological barriers, particularly the blood–brain barrier (BBB). In this study, we synthesized reduced graphene oxide (rGO) functionalized with quaternary ammonium pillar[5]arene (rGO-NMe₃P[5]A⁺) via noncovalent interactions, resulting in a positively charged surface (+28 mV). Doxorubicin (DOX) was loaded onto rGO-NMe₃P[5]A⁺ with a high efficiency of 99%, achieving a drug-loading capacity of 12.5% by weight. A pH-responsive drug release profile showed a cumulative release of 22% at pH 4.5 within 48 h, significantly higher than the 4% observed at pH 7.4. Cytotoxicity assays revealed that rGO-NMe₃P[5]A⁺-DOX reduced U251 Glioblastoma cell viability by 59% at a DOX concentration of 1 μg mL^–1, comparable to the 50% reduction observed with free DOX. Importantly, both unloaded and DOX-loaded rGO-NMe₃P[5]A⁺ demonstrated negligible toxicity to human brain microvascular endothelial cells (HBMEC), unlike free DOX, which reduced their viability by 60%. In vitro BBB model assays demonstrated the ability of rGO-NMe₃P[5]A⁺-DOX to cross the BBB and target Glioblastoma cells without compromising endothelial integrity. These findings highlight the potential of rGO-NMe₃P[5]A⁺-DOX as a biocompatible, efficient, and targeted platform for Glioblastoma treatment.

With the rapid advancement of infrared detection technologies, the demand for high-performance infrared stealth materials capable of operating under extreme conditions has become urgent. Traditional low-emissivity coatings offer some degree of infrared stealth; however, they suffer from thermal shock and uneven heat distribution when exposed to harsh environments. This highlights the critical need to develop materials that not only ensure infrared stealth performance but also possess exceptional mechanical strength and thermal stability under extreme conditions. Here, inspired by the distinctive thermoregulatory layered skin structure of desert lizards, the thermomechanically stable and thermally insulating carbon nanofiber aerogels with a curled, interlocked, and self-cross-linked fibrous structure were designed through humidity-induced phase separation and self-cross-linking strategies. The aerogels demonstrate resilience with over 96% stress retention after 1000 cycles, with an energy dissipation factor as low as 0.31. Moreover, they maintain superelasticity under extreme conditions, offering exceptional mechanical stability and thermal shock resistance across temperatures from −50 to 200 °C. Furthermore, the aerogels boast a low thermal conductivity of 0.030 W·m^–1·K^–1. Drawing additional inspiration from the highly reflective scale structure of the desert lizard’s epidermis, we designed aluminum foil-carbon composite aerogels by affixing high-reflectivity aluminum foil papers to the surface of the carbon aerogels, resulting in a composite with low infrared emissivity (0.24). In both extreme-cold (−196 °C) and high-temperature (400 °C) environments, the composite aerogels exhibit outstanding infrared stealth performance, fully illustrating their potential for use in demanding conditions.

Over the past decade, fully inorganic perovskite nanocrystals (NCs) have been proven to be efficient active materials for optoelectronic applications. The photoluminescence and stability properties of these nanostructures are demonstrated to be highly dependent on the surface chemistry and, specifically, on the surfactant molecules used to passivate the surface defects. Here, we present a study of the dependence of the amplified spontaneous emission (ASE) properties of CsPbBr₃ perovskite NC thin films, their photostability, and their sensitivity to ambient air on the NC capping ligand. In particular, in this work, four different samples have been analyzed, representatives of the three generations of capping ligands: oleic acid and oleylamine as the first generation, didodecyldimethylammonium bromide as the second generation, and 3-(N,N-dimethyloctadecylammonio)propanesulfonate (ASC18) and lecithin as the third generation. We discuss the different properties of quantum efficiency, optical gain, optical stability, and atmospheric sensing of NCs as a function of the four different ligands employed, focusing on the chemical–physical processes underlying the observed differences. We then establish the structures that ensure the best performances among the four studied physical characteristics. Among all of them, lecithin-capped NCs show the best performances in terms of ASE threshold and sensing. Our results could lay the groundwork for determining the optimal synthesis and processing conditions for perovskite NCs based on future technological applications.

Van der Waals (vdW) heterostructures based on two-dimensional (2D) transition-metal dichalcogenides (TMDs) without a crystal lattice matching constraint show great potential for high-performance optoelectronic devices. In this study, a Sb₂Te₃/WS₂ vdW heterostructure based on TMDs and topological insulators is fabricated for broadband photodetection spanning the visible to short-wave infrared wavelength bands, which demonstrates high responsivity, ambipolar photoresponse (negative and positive), self-powered, and polarization-sensitive detection capabilities. Due to special Z-scheme charge transfer and the efficient light-harvesting ability in the heterostructure, the device exhibits a broadband response ranging from 400 to 2200 nm, achieving a high responsivity of 0.429 A/W and a detectivity of 1.89 × 10⁹ Jones at 1 V bias under 1310 nm laser illumination. Furthermore, the devices demonstrate a high degree of linear polarization sensitivity, with a dichroic ratio of ∼2.2 at 650 nm and up to ∼4 at 1310 nm, primarily attributable to the anisotropy of light absorption and the stacking direction of the crystal. Overall, this study reveals the great potential of Sb₂Te₃/WS₂ vdW heterostructures for high-performance polarization-sensitive broadband photodetectors.

CuFeS_x (CFS) core–shell quantum dots (QDs) synthesized via a high-temperature colloidal chemistry route demonstrate unusually strong photobleaching of their luminescence under irradiation with blue light. Cw laser irradiation at λ = 440 nm results in a substantial drop in the photoluminescence (PL) output of CFS QDs in a polymeric film down on 80% of its initial value within a few seconds. The PL signal recovers within a relatively short time frame from hours to days, and such a process drastically speeds up by the sample heating to a mild temperature of ca. 50–70 °C. Comparative analysis of CFS, CuInS_x, and mixed CuFeInS_x core–shell QDs demonstrates the important role of Fe atoms in the formation of the nonemissive long-lived traps for photoexcited charges. Polymeric films impregnated with CFS QDs can be potentially used as the optical storage media for graphic or digital information with a multifold write-and-erase capability.

Recent advances in the 2D bismuth oxyselenide (Bi_xO_ySe_z) family have attracted significant attention owing to their remarkable stability and high electron mobility. However, achieving low-temperature and stoichiometry-tunable growth of 2D Bi_xO_ySe_z still remains challenging, which further hinders its practical applications. Herein, guided by thermodynamic calculations, two different types of Bi_xO_ySe_z products (Bi₂O₂Se and Bi₃O_2.5Se₂) can be successfully prepared. Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM) were systematically utilized to further confirm the crystal structure, elemental composition, and crystallinity of the as-synthesized Bi_xO_ySe_z. We reveal that both the Bi₂O₂Se- and Bi₃O_2.5Se₂-based field-effect transistors presented an n-type semiconductor behavior with the average field-effect mobilities of 10 and 15 cm² V^–1 s^–1. The Bi₃O_2.5Se₂ photodetector demonstrates outstanding photoresponse performance to the 532 nm light, with a responsivity of 28 A/W, a detectivity of 5.7 × 10⁹ Jones, and a rise/decay time of 3.4 ms/820 μs. Moreover, our Bi₃O_2.5Se₂ device exhibits a wide spectral response from the violet (365 nm) to near-infrared (1064 nm) regions. Our results not only propose an approach for low-temperature and stoichiometry-controlled wafer-scale synthesis of 2D Bi_xO_ySe_z but also showcase their potential for high-performance field-effect transistors and photodetectors.

Biocompatible CaCO₃ nanoclusters were prepared by using a simple biomineralization technique. Employing CaCO₃ nanoclusters in breast cancer treatment provides an exciting avenue for theranostics, which merges precise imaging with individualized treatment plans. They were highly suitable for improving the efficacy and precision of breast cancer detection and therapy with minimal adverse effects due to their biocompatibility, controlled drug release, pH sensitivity, and adaptability. In our current study, we proposed a palbociclib (PBB)-loaded fluorescent calcium nanocluster-based redox-sensitive drug delivery system for efficient breast cancer imaging and therapy. The developed nanoparticles were analyzed for their morphology and various physicochemical properties. The particle sizes of the formulated FNC-PBB-CS-NPs (nonredox-sensitive) and FNC-PBB-CS-SS-NPs (redox-sensitive) nanoparticles were 150.2 ± 2.1 and 160.4 ± 1.4 nm, respectively. The zeta potential of nonredox-sensitive nanoparticles was measured to be +17.12 ± 1.34 mV, while the zeta potential of redox-sensitive nanoparticles was +14.32 ± 1.17 mV. The entrapment efficiencies of FNC-PBB-CS-NPs and FNC-PBB-CS-SS-NPs were determined to be 88.74 ± 2.34 and 89.26 ± 1.21%, respectively. FNC-PBB-CS-SS-NPs demonstrated quicker drug release at acidic pH compared to FNC-PBB-CS-NPs. The cytotoxicity assay conducted on MCF-7 and T-47D cells indicated that FNC-PBB-CS-NPs and FNC-PBB-CS-SS-NPs exhibited greater cytotoxicities than free PBB. Furthermore, the Hoechst/PI dual-staining experiment demonstrated the superior activity of FNC-PBB-CS-SS-NPs over FNC-PBB-CS-NPs and free PBB. Ultrasound/photoacoustic imaging revealed that FNC-PBB-CS-SS-NPs effectively reduced tumor size, hypoxic tumor regions, and tumor vascularity compared to FNC-PBB-CS-NPs and free PBB. Additionally, in vivo optical imaging showed that the FNC-PBB-CS-SS-NPs accumulated more specifically in tumors than the other formulations.

Subcellular targeted therapy has recently emerged as a significant approach in cancer treatment. Mitochondria, as crucial organelles that not only provide cellular energy but also play roles in cell differentiation, signal transmission, reactive oxygen species production, apoptosis, and calcium homeostasis, are considered potential targets for cancer therapy. Silver sulfide quantum dots (Ag₂S QDs) have demonstrated exceptional capabilities in near-infrared fluorescence and photoacoustic imaging as well as photothermal treatment. Therefore, the development of Ag₂S QDs with mitochondrial-targeting ability is of particular significance. Herein, we developed a simple method for synthesizing aqueous-phase Ag₂S QDs using lipoic acid, an enzymatic substrate involved in cellular respiration, as a ligand and mitochondrial-targeting molecule. These Ag₂S QDs, which exhibit excellent water solubility and biocompatibility, can be produced in a single step and act as a mitochondrial-targeted theranostics. By adsorbing doxorubicin (DOX), we successfully created multifunctional nanoprobes called Ag₂S-DOX. In vitro and in vivo experiments demonstrated that Ag₂S-DOX was suitable for fluorescence and photoacoustic dual-mode imaging as well as synergistic mitochondrial-targeted chemotherapy and photothermal treatment, offering a promising strategy for tumor therapy.

Mold has long been a priority because of its potential threat to human health and reduction in the value of wood. Most of the traditional mold inhibitors have toxic effects on the environment, so developing safe and nontoxic mold inhibitors remains a challenge. In this study, tannic acid carbon dots (TA-CDs) were obtained via a straightforward one-step hydrothermal process. Subsequently, Cu²⁺ cross-linked tannic acid carbon dot nanoparticles (TA-CDs-Cu²⁺) were synthesized by introducing Cu²⁺ to TA-CDs at room temperature. The TA-CDs-Cu²⁺ can be firmly anchored on the surface of Aspergillus niger spores, triggering the rapid release of Cu²⁺ and TA-CDs in the localized acidic environment. The released TA-CDs triggered the conversion of Cu²⁺ to Cu⁺, destroying the cell wall and cell membrane structure of A. niger and reducing cellular esterase activity. In addition, TA-CDs-Cu²⁺ has been demonstrated to diminish the biomass of biofilms markedly. The use of TA-CDs-Cu²⁺ on poplar and birch wood has achieved mold protection class 0 at 20 mg of Cu/mL, which were found to exhibit unparalleled advantages as a mold inhibitor. Meanwhile, the TA-CDs-Cu²⁺ has a warming effect and has opened up avenues for the design of mold inhibition therapeutic agents and photothermal synergistic mold inhibition.

Nanoporous covalent organic frameworks (COFs) exhibit exceptional potential as sensitive materials for gas sensors due to their film-forming capabilities and tunable host–guest interactions. This study addresses the challenge of selectively detecting H₂S gas by developing an optical waveguide gas sensor (OWGS) utilizing [H₄bptc-(TAPT)₃]_n-COF films (Here, H₄bptc refers to biphenyl- 3,3′,5,5′-tetracarboxylic acid, and TAPT represents 2,4,6-tris(4-aminophenyl)-1,3,5-triazine). These films were fabricated by immobilizing COFs on TiO₂ substrates via a solvothermal reaction, followed by surface optimization using a layer-by-layer assembly method. This assembly method induced a structural transformation in the [H₄bptc-(TAPT)₃]_n-COF films, progressing from densely layered structures to a graphene-like architecture and eventually forming more intricate configurations. Among these, the 3-layered [H₄bptc-(TAPT)₃]_n-COF film demonstrates a graphene-like structure and achieved rapid (<2 s) and selective response to H₂S gas, with notable refractive index changes upon proton transfer. The Density-functional theory (DFT) calculations revealed the highest binding energy between the triazine ring in [H₄bptc-(TAPT)₃]_n-COF and H₂S molecules. The sensor exhibited excellent selectivity, a broad detection range (100 ppm-1 ppb), outstanding reproducibility, moisture resistance, and an ultralow detection limit of 1.07 ppb at room temperature. Additionally, the H₂S adsorption process was determined as endothermic, with an adsorption capacity of 10.98 ng·cm^–2 at 293 K.