Nanotechnology最新文献

A common strategy in cancer therapy involves using a nanoscale carrier to simultaneously deliver phototherapeutic agents and chemotherapeutic drugs. However, traditional delivery carriers are toxic and immunogenic, and their preparation involves complex procedures, limiting their widespread application. Exosomes, are spherical, lipid bilayer vesicles ranging from 50 to 150 nm in diameter, which are naturally secreted by various cells, and can cross various biological barriers, making them attractive alternatives. Dunaliella salina-derived exosome-like nanovesicles (DENVs) represent promising drug nanocarriers owing to their favorable bio-compatibility, low immunogenicity, cost-effective, large-scale, and rapid production. However, the role of DENV in triple-negative breast cancer (BC) remains unknown. In this study, DENV were prepared by ultracentrifugation. Indocyanine green (ICG) and 5-fluorouracil (5-FU) were co-loaded into DENV (DENV-ICG/5-FU) via electroporation. DENV-ICG/5-FU exhibited good photothermal performance and stability. At a pH of 5.0 and exposure to 808 nm near-infrared (NIR) light (1 W cm^-2, 5 min), the cumulative release of 86.45% for 5-FU from the DENV-ICG/5-FU was observed. In addition, DENV-ICG/5-FU was internalized into 4T1 cells. Under NIR irradiation, it inhibited proliferation and migration and induced apoptosis of 4T1 cells. Results from flow cytometry and DCFH-DA analyses indicated that NIR irradiation markedly elevated both the percentage of cells in the G1 phase and the generation of reactive oxygen species. Mechanistic studies showed that under NIR irradiation, DENV-ICG/5-FU enhanced the expression of the pro-apoptotic protein Bax. In conclusion, these findings suggest that DENV could be ideal vehicles to co-deliver phototherapeutic agents and chemotherapeutic drugs for synergistic tumor treatment.

A flexible buckypaper attached with NiO and CoO (NiO-CoO-BP) was fabricated for electrochemical detection of glucose, exhibiting the characteristics of high conductivity, selectivity, sensitivity and a wide detection range. NiO-CoO-BP comprises two arc discharge-synthesized single-walled carbon nanotube (SWCNT) types. The bottom is a supporting layer of high-crystallinity, high-conductivity purified SWCNT (P-SWCNT) networks, and the upper is a catalytic active layer of SWCNTs loaded with NiO-CoO nanoparticles. The two SWCNT types were combined via vacuum filtration to form a membrane structure. A thermal field scanning electron microscope was used to characterize the morphology of NiO-CoO-BP, while an x-ray diffractometer and Raman spectroscopy were employed to determine its structure. Under optimized conditions, the electrochemical test of the flexible glucose sensor constructed with NiO-CoO-BP exhibited a wide linear range of 2-20 mM, a sensitivity of up to 3789.17μA·mM^-1·cm^-2, and a low detection limit of 37μM. The test results of this work indicate that flexible NiO-CoO-BP composed of P-SWCNTs and NiO-CoO-SWCNTs has great application prospects in wearable biosensors.

The miniaturization of organic nonlinear optical crystals is critical for integrated photonics but remains fundamentally challenged by the drastic decline of nonlinear signals at sub-wavelength scales. While the surface plasmon resonance (SPR) of metallic nanostructures can concentrate local fields to enhance nonlinear processes, harnessing this effect effectively for organic crystals is nontrivial. Here, we exploit a three-dimensional nanoporous gold (NPG) substrate to form a hybrid composite with 4-N, N-dimethylamino-4'-N'-Methyl-stilbazolium tosylate (DAST). This NPG-DAST hybrid achieves a remarkable enhancement of second harmonic generation, with an absolute conversion efficiency of 1.22 × 10^-⁹ two orders of magnitude higher than the 1.63 × 10^-11obtained on silicon under identical excitation. This corresponds to a 75-fold intensity enhancement at 515 nm compared to DAST on flat silicon. This dramatic enhancement primarily originates from the dual-resonant plasmonic effect of the NPG substrate, where the localized SPRs are efficiently excited at both the fundamental (1030 nm) and the second-harmonic (515 nm) wavelengths, synergistically amplifying the local field and the nonlinear conversion process. This work provides a compelling strategy to overcome the fundamental limitation of signal reduction in miniaturized organic nonlinear optical materials, demonstrating significant potential for their application in micro- and nano-optoelectronic devices.

Temperature monitoring is widely applied across various industries, with temperature sensors being essential for monitoring temperature conditions in processes within the fields such as aerospace, industrial production, and healthcare. However, most existing traditional temperature sensors operate at temperatures below 200 °C, which fails to meet the high-temperature monitoring requirements of many application scenarios. Therefore, we propose a graphene-based high-temperature durable temperature sensor with a composite protective layer composed of silicon nitride (SiN_x) and aluminum oxide (Al₂O₃). This novel composite protective layer effectively prevents the oxidation of graphene at high temperatures, enabling the temperature sensor to operate over extended periods under such conditions. The sensor has a maximum tolerance temperature of 600 °C and a temperature measurement range of 50 °C-600 °C. The resistance of the device increases with rising temperature, exhibiting a positive temperature coefficient, with a maximum average temperature coefficient of resistance value of 0.17 ± 0.015% °C^-1(mean ± s.d.,n= 3). Critically, experimental tests have demonstrated that our temperature sensor not only offers a wide temperature measurement range but also can continuously operate for over four hours at extremely high temperatures (500 °C). This study addresses the challenge of graphene's inability to function over the long term at high temperatures by proposing a new protective structure, holding promise for applications in long-term high-temperature scenarios such as energy and power generation and metallurgical processes.

The application of nano-cerium dioxide (CeO₂) lubricating oil in diesel engines demonstrates excellent friction-reduction and anti-wear properties. However, the impact of nano-CeO₂lubricating oil consumption on the particle size distribution of particulate matter (PM), especially micro/nano-sized PM, remains unclear. This problem has affected the active design of the control strategy of the after-treatment system and restricted the further promotion and commercialization of nano-CeO₂lubricating oil in engine applications. This study conducts a comparative investigation on the particle size distribution and microscopic morphology of PM influenced by nano-CeO₂additives in lubricating oil. The results indicate that, compared to pure lubricating oil (PLO), the use of nano-CeO₂lubricating oil significantly increases the total number of nucleation-mode and accumulation-mode particles. Under 10%, 25%, 50%, 75% and 100% load conditions, the concentration of particles with a diameter less than 100 nm corresponding to the nano-CeO₂lubricating oil was approximately twice, seven times, twelve times, seventeen times and six times that of PLO, respectively. At rotational speeds of 2000 r min^-1, 2250 r min^-1, 2500 r min^-1, 2750 r min^-1and 3000 r min^-1, the concentration of particles with a diameter less than 100 nm corresponding to the nano-CeO₂lubricating oil is approximately five times, two times, five times, six times and five times that of PLO, respectively. Microscopic analysis reveals that PM corresponding to PLO exhibits uniform primary carbon particle sizes, whereas PM corresponding to nano-CeO₂lubricating oil contains a higher quantity of smaller primary carbon particles. This confirms that nano-CeO₂particles undergo self-nucleation during combustion, thereby increasing the risk of generating additional nucleation-mode particles.

This study employs photo-induced force microscopy (PiFM) and Raman spectroscopy to investigate how oxidative treatments (HNO₃vs HNO₃/H₂SO₄) influence functional group distribution and morphology of carbon nanotubes. Raman spectral analysis revealed distinct oxidation mechanisms introducing functional groups and structural defects between the two acid treatments. Comparison of PiFM mapping images of C-O-C (at 1100 cm^-1) and C=O containing groups (at 1730 cm^-1) between the two treatments further highlighted these differences: mixed acid oxidation induced localized carbonyl formation and tube shortening, while HNO₃treatment resulted in longitudinal functionalization that preserves tube length.

Quantum spin-liquid (QSL) ground state emerges in frustrated magnetic systems where competing interactions suppress long-range magnetic ordering. TbInO3, a hexagonal perovskite, shows QSL behaviour due to geometrical frustration and strong spin-orbit coupling present in it. Here, we report the strain-driven modification of the magnetic ground state and the enhancement of magnetic frustration at milli-Kelvin (mK) temperature (<1 K) in the TbInO3 epitaxial thin film, grown on MgO (100) substrate. We observe a Curie-Weiss crossover at 1-30 K temperature, strong antiferromagnetic interactions, along with the absence of long-range ordering down to 400 mK, consistent with a QSL ground state. Notably, the thin film exhibits a significantly enhanced effective moment in the mK range compared to the bulk, attributed to strain-induced modification of the exchange pathway among Tb 3+ ions. This impact broadens the QSL state's temperature range to lower temperatures and enhances magnetic frustration in the temperature-field phase space. Further, the first-principles calculation also supports the enhancement of frustration in thin film. These findings demonstrate that strain-induced tuning of exchange interactions can enhance the magnetic frustration, offering a route to stabilise QSL phases down to lower temperatures in hexagonal perovskite thin films.

Polyethylene glycol (PEG)-capped gold nanoparticles (PEG-AuNPs) are of great interest for targeted drug delivery and targeted delivery of chemotherapy due to their biocompatibility and ability to evade detection by the immune system. However, with repeated administration, the accelerated blood clearance (ABC) phenomenon can significantly reduce the circulation time of nanoparticles and alter key pharmacokinetic parameters. This study aims to evaluate whether pretreatment with free PEG before the administration of PEG-AuNPs can improve their pharmacokinetics and reduce the ABC effect, compared to the administration of PEG-AuNPs alone. AuNPs were synthesized using the Turkevich-Frens method, PEGylated, and characterized by ultraviolet-visible spectroscopy (UV-Vis), Dynamic light scattering (DLS), zeta potential (ZP) measurement, and transmission electron microscopy (TEM). The synthesized PEG-AuNPs were spherical with a core diameter of 19.54 ± 1.758 nm. To evaluate the effect of free PEG, two groups of rats were given an initial dose of PEG-AuNPs. Both groups then received a second dose, but only the second group was pretreated with free PEG before PEG-AuNPs administration. Gold concentrations in plasma and various organs were quantified using a validated inductively coupled plasma mass spectrometry (ICP-MS) method, and pharmacokinetic parameters were subsequently determined. The ABC index confirmed the presence of the ABC phenomenon when comparing the first and the second doses of PEG-AuNPs. Unexpectedly, pretreatment with free PEG did not significantly alter the pharmacokinetic parameters (C_max,t_max, andt_0.5;p> 0.05) compared to the condition without pretreatment with free PEG. Accumulation of PEG-AuNPs in the liver and spleen increased by (6-7) and (2-3)-fold, respectively, after the administration of the second dose, compared to the first dose, which is consistent with the concept of the ABC phenomenon. In conclusion, under the experimental conditions of this study, the strategy of pretreatment with free PEG before the second dose did not significantly alleviate the effect of the ABC phenomenon in the context of PEG-AuNPs.

In this work, we have fabricated the blue micro-light-emitting diodes (micro-LEDs) with 0, 8, 10 and 12 periods of SiO₂/TiO₂ anti-reflection (AR) films by using the technology of atomic layer deposition. In addition, by measuring the properties of these AR films and the optoelectronic performance of these micro-LEDs, the impacts of these AR films for these micro-LEDs have been analyzed. For the poorer thermal dissipation characteristics of SiO₂ and TiO₂ than that of air, there would be lower resistance in the micro-LEDs with more periods of AR films under high current injected condition. In addition, the optical properties of these AR films result in the higher external quantum efficiency in the micro-LEDs with more periods of AR films, and the light distribution of micro-LEDs with 0, 2, 4, 6, 8, 10, 12 and 14 periods of AR films has been analyzed by using the FDTD software. Moreover, the junction-temperature rise and the stability of these micro-LEDs has been investigated by using the 1000 h accelerating aging test under (85 °C/85% humidity) under the injection current of 40 mA, these results indicate that AR films have excellent reliability under 85 °C and 85% humidity conditions, and the deposition of AR films would result in the poorer thermal behavior in micro-LEDs. We hope these findings could give reference for the fabrication of high-performance micro-LEDs.

In this study, the tunable synthesis of resorcinol-formaldehyde (RF) resins from resorcinol and formaldehyde, with ammonia as a catalyst, was investigated. RF resins with uniform sphere sizes were successfully prepared by optimizing the concentrations of resorcinol and ammonia. The resin spheres were subsequently carbonized into amorphous carbon spheres with slightly smaller diameters. The selection of reaction parameters enabled the adjustment of RF carbon sphere (RFCS) diameters within the range of 179 to 1546 nm. The prepared RFCSs exhibited type I adsorption isotherms, and the pore size distribution was dominated by micropores (1.9-1.6 nm), with a Brunauer-Emmett-Teller surface area of 479-650 m2/g. X-ray diffraction and Raman spectroscopy confirmed the presence of amorphous carbon with a high defect density in RFCSs. Fourier transform infrared spectroscopy indicated incomplete carbonization of RF resins, resulting in the retention of a substantial number of functional groups on their surfaces. Adsorption tests showed that RFCSs synthesized with 0.6 mL ammonia and 1.2 g resorcinol at the carbonization temperature of 800 °C exhibited the highest adsorption capacity for Cd(II) (813 mg/g), demonstrating their potential as effective adsorbents for heavy metal removal from wastewater. In conclusion, RFCSs are promising as an excellent matrix material for further modification and performance enhancement across diverse applications due to their regular spherical shape, adjustable pore size, hydrophobic surface, outstanding performance and low-cost preparation.