Nanoscale Horizons最新文献

Single-walled carbon nanotubes (SWCNTs) are synthesized as mixtures of various SWCNT types, exhibiting drastically different properties, and thereby making the material of limited use. Fluorene-based polymers are successful agents for purifying such blends by means of conjugated polymer extraction (CPE), greatly increasing their application potential. However, a limited number of studies have devoted attention to understanding the effects of the polyfluorene backbone and side chain structure on the selectivity and separation efficiency of SWCNTs. Regarding the impact of the polymer backbone, it was noted that the ability to extract SWCNTs with conjugated polymers could be significantly enhanced by using fluorene-based copolymers that exhibit dramatically different interactions with SWCNTs depending on the types of monomers combined. However, the role of monomer side chains remains much less explored, and the knowledge generated so far is fragmentary. Herein, we present a new approach to tailor polymer selectivity by creating copolymers of polyfluorene bearing mixed-length alkyl chains. Their thorough and systematic analysis by experiments and modeling revealed considerable insight into the impact of the attached functional groups on the capacity of conjugated polymers for the purification of SWCNTs. Interestingly, the obtained results contradict the generally accepted conclusion that polyfluorene-based polymers and copolymers with longer chains always prefer SWCNTs of larger diameters. Besides that, we report that the capacity of such polymers for sorting SWCNTs may be substantially enhanced using specific low molecular weight compounds. The carried-out research provides considerable insight into the behavior of polymers and carbon-based materials at the nanoscale.

Quantum sensing using the fluorescent nanodiamond (FND) nitrogen-vacancy center enables physical/chemical measurements of the microenvironment, although application of such measurements in living mammals poses significant challenges due to the unknown biodistribution and toxicity of FNDs, the limited penetration of visible light for quantum state manipulation/measurement, and interference from physiological motion. Here, we describe a microenvironmental thermometry technique using FNDs in rat mammary epithelium, an important model for mammary gland biology and breast cancer research. FNDs were injected directly into the mammary gland. Microscopic observation of mammary tissue sections showed that most FNDs remained in the mammary epithelium for at least 8 weeks. Pathological examination indicated no obvious change in tissue morphology, suggesting negligible toxicity. Optical excitation and detection were performed through a skin incision. Periodic movements due to respiration and heartbeat were mitigated by frequency filtering of the signal. Based on these methods, we successfully detected temperature elevation in the mammary epithelium associated with lipopolysaccharide-induced inflammation, demonstrating the sensitivity and relevance of the technique in biological contexts. This study lays the groundwork for expanding the applicability of quantum sensing in biomedical research, providing a tool for real-time monitoring of physiological and pathological processes.

Introducing metallic nanoparticles, such as Au, on a substrate as a surfactant or wetting inducer has been demonstrated as a simple but effective way to facilitate the formation of ultra-thin silver layers (UTSLs) during the subsequent Ag deposition. However, most studies have paid much attention to the applications of UTSLs assisted by metallic surfactants but neglected the underlying mechanisms of how the metallic surfactant affects the formation of UTSL. Herein, we have applied in situ grazing-incidence wide-/small-angle X-ray scattering to reveal the effects of the Au surfactant or seed layer (pre-deposited Au nanoparticles) on the formation of UTSL by high-power impulse magnetron sputter deposition (HiPIMS) on a zinc oxide (ZnO) thin film. The comprehensive and in-depth analysis of the in situ X-ray scattering data revealed that the pre-deposited Au nanoparticles can act as additional defects or growth cores for the sputtered Ag atoms despite using HiPIMS, which itself forms many nucleation sites. As a result, the formation of a continuous and smooth UTSL is reached earlier in HiPIMS compared with bare ZnO thin films. Based on the mechanism revealed by the in situ measurements, we provide insight into the formation of UTSL and further UTSL-based applications.

Crystal defects, traditionally viewed as detrimental, are now being explored for quantum technology applications. This study focuses on stacking faults in silicon and germanium, forming hexagonal inclusions within the cubic crystal and creating quantum wells that modify electronic properties. By modeling defective structures with varying hexagonal layer counts, we calculated the formation energies and electronic band structures. Our results show that hexagonal inclusions in Si and Ge exhibit a direct band gap, changing with inclusion thickness, effectively functioning as quantum wells. We find that Ge inclusions have a direct band gap and form type-I quantum wells. This research highlights the potential of manipulating extended defects to engineer the optoelectronic properties of Si and Ge, offering new pathways for advanced electronic and photonic device applications.

The protection of silver nanowire (AgNW) networks is crucial for enhancing their durability and applicability to flexible electronics. In this study, we present a sustainable and efficient strategy to protect AgNW-based flexible transparent electrodes (FTEs) using a layer-by-layer (LBL) assembly of biorenewable chitin and cellulose nanofibers (Chi and Cell). These uniform LBL-assembled thin films were successfully fabricated on AgNW FTEs due to their opposite surface charges. The resulting (Chi/Cell)_n bilayers, where n is the number of bilayers, did not degrade the optoelectrical properties of AgNW FTEs and significantly enhanced their stability under various harsh conditions. The optimized (Chi/Cell)₁₀@Al-AgNW FTEs exhibited comprehensive stability against UV/O₃ treatment for 40 min, thermal treatment at 250 °C for 350 min, Na₂S (1%), HCl (10%), and NH₃ (30%) treatments for 3, 30, and 105 min, respectively, sonication for 300 min, and 10 000 cycles of bending test. Therefore, the (Chi/Cell)₁₀@Al-AgNW FTEs were successfully applied to transparent heaters (TH) and pressure sensors with remarkably improved applicability, durability, and performance compared to pristine AgNW FTEs, providing a reassuring solution to the stability issues of AgNW-based FTEs.

Correction for ‘New horizons on advanced nanoscale materials for Cultural Heritage conservation’ by Rosangela Mastrangelo et al., Nanoscale Horiz., 2024, 9, 566–579, https://doi.org/10.1039/D3NH00383C.

This article highlights the recent work of Biju, Takano et al. (Nanoscale Horiz., 2024, 9, 1128–1136, https://doi.org/10.1039/D4NH00134F) on using a unique bio-catalytic nanoparticle shaping method for preparing mesoscopic particles.

This study explores the phase-controlled growth of few-layered 2H-MoTe₂, 1T′-MoTe₂, and 2H-/1T′-MoTe₂ heterostructures and their impacts on metal contact properties. Cold-wall chemical vapor deposition (CW-CVD) with varying growth rates of MoO_x and reaction temperatures with Te vapors enabled the growth of continuous thin films of either 1T′-MoTe₂ or 2H-MoTe₂ phases on two-inch sapphire substrates. This methodology facilitates the meticulous optimization of chemical vapor deposition (CVD) parameters, enabling the realization of phase-controlled growth of few-layered MoTe₂ thin films and their subsequent heterostructures. The study further investigates the influence of a 1T′-MoTe₂ intermediate layer on the electrical properties of metal contacts on few-layered 2H-MoTe₂. Bi-layer Ti/Al contacts directly deposited on 2H-MoTe₂ exhibited Schottky behavior, indicating inefficient carrier transport. However, introducing a few-layered 1T′-MoTe₂ intermediate layer between the metal and 2H-MoTe₂ layers improved the contact characteristics significantly. The resulting Al/Ti/1T′-MoTe₂/2H-MoTe₂ contact scheme demonstrates Ohmic behavior with a specific contact resistance of around 1.7 × 10⁻⁴ Ω cm². This substantial improvement is attributed to the high carrier concentration of the 1T′-MoTe₂ intermediate layer which could be attributed tentatively to the increased tunneling events across the van der Waals gap and enhancing carrier transport between the metal and 2H-MoTe₂.

Sonodynamic therapy (SDT) is gaining popularity in cancer treatment due to its superior controllability and high tissue permeability. Nonetheless, the efficacy of SDT is severely diminished by the transient generation of limited reactive oxygen species (ROS). Herein, we introduce an acid-activated nanosonosensitizer, CaO₂@PCN, by the controllable coating of porphyrinic metal–organic frameworks (PCN-224) on CaO₂ to induce cascaded oxidative stress in tumors. The PCN-224 doping can generate ROS during SDT to induce intracellular oxidative stress and abnormal calcium channels. Meanwhile, the ultrasound also promotes extracellular calcium influx. In addition, CaO₂@PCN sequentially degrades in the tumor cell lysosomes, releasing Ca²⁺ and H₂O₂ to induce further abnormal calcium channels and elevate the levels of Ca²⁺. Insufficient catalase (CAT) in tumor cells promotes intracellular calcium overload, which can induce persistent ROS generation and mitochondrial dysfunction through ion interference therapy (IIT). More importantly, PCN-224 also protects CaO₂ against significant degradation under neutral conditions. Hence, the well-designed CaO₂@PCN produces synergistic SDT/IIT effects and persistent ROS against cancer. More notably, the acidity-responsive biodegradability endows CaO₂@PCN with excellent biosafety and promising clinical potential.

Immune profiling provides insights into the functioning of the immune system, including the distribution, abundance, and activity of immune cells. This understanding is essential for deciphering how the immune system responds to pathogens, vaccines, tumors, and other stimuli. Analyzing diverse immune cell types facilitates the development of personalized medicine approaches by characterizing individual variations in immune responses. With detailed immune profiles, clinicians can tailor treatment strategies to the specific immune status and needs of each patient, maximizing therapeutic efficacy while minimizing adverse effects. In this review, we discuss the evolution of immune profiling, from interrogating bulk cell samples in solution to evaluating the spatially-rich molecular profiles across intact preserved tissue sections. We also review various multiplexed imaging platforms recently developed, based on immunofluorescence and imaging mass spectrometry, and their impact on the field of immune profiling. Identifying and localizing various immune cell types across a patient's sample has already provided important insights into understanding disease progression, the development of novel targeted therapies, and predicting treatment response. We also offer a new perspective by highlighting the unprecedented potential of nanoparticles (NPs) that can open new horizons in immune profiling. NPs are known to provide enhanced detection sensitivity, targeting specificity, biocompatibility, stability, multimodal imaging features, and multiplexing capabilities. Therefore, we summarize the recent developments and advantages of NPs, which can contribute to advancing our understanding of immune function to facilitate precision medicine. Overall, NPs have the potential to offer a versatile and robust approach to profile the immune system with improved efficiency and multiplexed imaging power.