Nm In Diameter Research Articles

Proteinoid-polyaniline neuromorphic composites for audio recognition

Abstract We present an innovative neuromorphic system using a proteinoid-polyaniline (PANI) composite for recognition of audio inputs of the English alphabet. Neuromorphic devices, which draw inspiration from the neural networks of the brain, have emerged as very promising potential solutions for efficient signal processing. The proteinoid-PANI composite was synthesized through a template-free method, resulting in a unique nanostructure consisting of both nanorods and nanospheres. Principal component analysis (PCA), spectrogram analysis, and temporal spiking response analysis were among the signal processing methods used to examine the composite's audio response to English alphabet stimuli. The system showed a moderate positive correlation between input and output signals, unique time-frequency response patterns, and convoluted spiking behaviour. In addition, the output amplitude showed less variation compared to the input, while maintaining the same temporal characteristics.
Microscopic analysis provided detailed information about the morphology of the composite. The nanorods displayed an optimal aspect ratio and had diameters of around 
100~nm, while the nanospheres varied in size, ranging from 200 to 500~nm in diameter. The nanostructure, morphological characteristics, and signal processing properties of the proteinoid-PANI composite demonstrate its potential for advanced applications in neuromorphic computing and signal processing, particularly in speech recognition and human-machine interaction.

Membrane mechanics dictate axonal pearls-on-a-string morphology and function.

Axons are ultrathin membrane cables that are specialized for the conduction of action potentials. Although their diameter is variable along their length, how their morphology is determined is unclear. Here, we demonstrate that unmyelinated axons of the mouse central nervous system have nonsynaptic, nanoscopic varicosities ~200 nm in diameter repeatedly along their length interspersed with a thin cable ~60 nm in diameter like pearls-on-a-string. In silico modeling suggests that this axon nanopearling can be explained by membrane mechanical properties. Treatments disrupting membrane properties, such as hyper- or hypotonic solutions, cholesterol removal and nonmuscle myosin II inhibition, alter axon nanopearling, confirming the role of membrane mechanics in determining axon morphology. Furthermore, neuronal activity modulates plasma membrane cholesterol concentration, leading to changes in axon nanopearls and causing slowing of action potential conduction velocity. These data reveal that biophysical forces dictate axon morphology and function, and modulation of membrane mechanics likely underlies unmyelinated axonal plasticity.

Comparison of different self-assembly methods for formation of a homogenous monolayer of polystyrene

Abstract In this paper, we report on the formation of nanomasks by polystirene (PS) spheres as small as 150 nm in diameter using different self-assembly methods. Spin coating method was the most efficient. The influence of spin speeds, spinning time, solution quantity is studied in order to achieve a large area close-packed monolayer. A relatively high surface coverage and uniform monolayer of PS spheres can be achieved by appropriate control of the preparative parameters. It can be useful in industrial applications, because of the fabrication speed, surface coverage, control over PS spheres and cost of the process.

Natural Nano-emulsions: A Sustainable Solution for Rice Weevil Control in Stored Paddy Rice

Nanoemulsion technology offers a promising method to enhance the absorption and effectiveness of various active compounds. This study specifically developed nanoemulsions of frankincense, turmeric, and sesame oil to assess their impact on paddy rice. Notably, there is a lack of research examining both the efficacy and long-term effects of nanoemulsion treatments on rice quality, as most existing studies focus primarily on immediate harmful effects or repellent capabilities without considering prolonged impacts. This research is pioneering in exploring how nanoemulsion treatments influence the physical and chemical properties, nutritional value, and overall quality of paddy rice, as well as their effects on the rice weevil, (Sitophilus oryzae L., Coleoptera: Curculionidae). Nanoemulsions were prepared using a high-energy ultrasonication process and characterized by transmission electron microscopy, revealing spherical particles ranging from 27-34 nm in diameter. The formulations exhibited kinetic stability, slight acidity (pH 5.0–6.33), and favorable physicochemical properties including zeta potential (-31.6 to -15.2 mV), viscosity (27-34 cP), and surface tension (28.12-53.59 dyne/cm). The nanoemulsions were applied to paddy rice of the Sakha 108 cultivar at concentrations of 500, 1500, and 2000 μL/kg. Over 9 months of storage, the sesame nanoemulsion at 2000 μL/kg significantly improved milling quality (71.78% vs 70.23% in controls), hardness (7.25 N vs 5.40 N), and cooking properties. It also enhanced nutritional content, increasing vitamin B3 to 51.12 mg/kg (vs 44.63 mg/kg in controls), potassium to 1149 mg/kg (vs 1113 mg/kg), and phosphorus to 1133 mg/kg (vs 1064 mg/kg). The nanoemulsions demonstrated robust insecticidal effects against S. oryzae. The turmeric formulation at 2000 μL/kg achieved 100% adult mortality after two weeks and complete inhibition of progeny emergence over 9 months. Sesame and frankincense nanoemulsions at the same concentration resulted in 90% and 83.33% mortality, respectively, after two weeks. These findings demonstrate the potential of nanoemulsion technology as an environmentally friendly alternative to conventional chemical treatments for maintaining rice quality and providing effective pest control during long-term storage.

High-molecular-weight oligomer tau (HMWoTau) species are dramatically increased in Braak-stage dependent manner in the frontal lobe of human brains, demonstrated by a novel oligomer Tau ELISA with a mouse monoclonal antibody (APNmAb005).

Disease-specific oligomers Tau assay system is anticipated in Alzheimer disease (AD) to elucidate their etiological roles. We developed a highly sensitive and selective ELISA for high-molecular-weight oligomer tau (HMWoTau) with LLOQ of 0.3 pg/well for the first time, using a novel mouse monoclonal antibody APNmAb005. The target molecule was identified as HMWoTau with circa 2000 kD as a minimum size and the more oligomerized species (>5000 kD), in combination analysis with Size-Exclusion-Chromatography and Sucrose-Density-Gradient-Centrifugation for both recombinant human (rh) Tau-derived aggregates and AD brain-lysates in PBS(-). HMWoTau was labeled by Thioflavin S and visualized as a homogeneous globular particle (about 30 nm in diameter) by two different technologies of atomic force microscopy and dSTORM-Nanoimager. Specific quantitation was also confirmed by immune-absorption, rhHMWoTau-spiked, and cross-reactivity studies. APNmAb005 failed to detect the HMWoTau signal by treatment with DTT/SDS under no influence on the pan-tau antibody, indicating its conformation-specific recognition. APNmAb005-ELISA showed AD-specific and statistically significant ELISA signals from 1 ng brain lysate protein/well. Analysis of the frontal neocortex (N = 40, Braak stage I-VI) by ELISA revealed the detection-limit levels of HMWoTau species at stage I-III, and drastic and statistically significant increases at stage V/VI (AD). By contrast, total Tau and p181 Tau showed 1/4-1/5 levels of AD even at Stage I, while both tau species also showed a statistically significant increase in AD. In sum, our novel APNmAb005-ELISA clarified the disease-specific increase in HMWoTau species and will be useful for not only further etiological elucidation but also the potential diagnostics in AD and relevant tauopathy.

Development of triple-helical recombinant collagen-silver hybrid nanofibers for anti-methicillin-resistant Staphylococcus aureus (MRSA) applications

The escalating threat of healthcare-associated infections highlights the urgent need for biocompatible antibacterial materials that effectively combat drug-resistant pathogens. In this study, we present a novel fabrication method for triple-helical recombinant collagen (THRC)-silver hybrid nanofibers, specifically designed for anti-methicillin-resistantstaphylococcus aureus(MRSA) applications. Utilizing a silver-mediated crosslinking strategy, we harness a low-power 38 W lamp to enable silver ions (Ag+) to mediate crosslinking across various proteins. Mechanistic insights reveal the pivotal role of nine amino acids in facilitating this reaction. The THRC maintains its native structure, forming well-ordered nanofibers, while other globular proteins form a distinctive network-like structure. THRC also serves as a reducing and dispersing agent, facilitating thein situsynthesis of highly dispersed silver nanoparticles (AgNPs) (∼7 nm in diameter) within the nanofibers. Systematic investigation of the reaction conditions between THRC and Ag+demonstrates the versatility of this novel approach for nanofiber fabrication. The incorporation of AgNPs imparts exceptional antibacterial activity to the THRC/AgNPs nanofibers, exhibiting a minimum inhibitory concentration of 19.2 mg l-1and a minimum bactericidal concentration of 153.6 mg l-1against MRSA. This innovative approach holds significant potential for developing antibacterial protein-based biomaterials for infection management in wound healing and other biomedical applications.

Upshot of temperature on multi-walled carbon nanotubes synthesized Via CVD aided spray pyrolysis and its application towards lead ion removal from waste water

Rosmarinus officinalis was used in CVD Aided Spray Pyrolysis is to produce multi-walled carbon nanotubes (MWNTs) with a Fe-Co-Mo catalyst supported on silica using argon inert environment. The temperature at which MWNTs were formed varied from 550 to 750 °C. Scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), X-ray diffraction analysis, and Raman spectrum measurements were employed to characterize the as-grown MWNTs. HRTEM and Raman spectroscopy learning validated the progress of MWNTs 20–30 nm in diameter. The viability of using as-grown MWNTs as an adsorbent for removing Pb (II) ions from drinking water was studied. The Langmuir and Freundlich equations were exploited to interpret adsorption isotherm data. Kinetic data was analyzed by means of Elovich, pseudo-first-order, and pseudo-second-order equations.

Cationic Lipid Derived from a Basic Amino Acid: Design and Synthesis

One of the major challenges in gene therapy is the efficient and safe introduction of nucleic acids into eukaryotic cells. This process requires overcoming various biological barriers and navigating complex pathways to reach target cells and achieve their biological function. To address this obstacle, numerous transfection methods have been developed, including physical techniques and the use of genetic vectors, both viral and non-viral. However, to date, no transfection method is 100% safe and efficient. Within the spectrum of non-viral genetic vectors, cationic liposomes formed by cationic lipids stand out for their ability to protect and deliver therapeutic NA. These liposomes offer greater biocompatibility and lower immunogenicity compared to viral vectors, although they still do not match the efficiency of viral delivery systems. Consequently, ongoing research focuses on synthesizing a wide variety of cationic lipids in the search for compounds that provide high transfection efficiency with minimal cytotoxicity. This study aimed to design and synthesize a novel cationic lipid (CholCadLys) derived from natural cellular molecules for transferring genetic material to eukaryotic cells. The lipid was synthesized using cholesteryl chloroformate for the hydrophobic region, cadaverine as a linker, and lysine for the polar region, connected by carbamate and amide bonds, respectively. Identification was confirmed through thin-layer chromatography, purification through preparative chromatography, and characterization via infrared spectroscopy and mass spectrometry. The synthesis yielded a 60% success rate, with stable nanoliposomes averaging 76 nm in diameter. Liposomes were formed using this CL and commercial neutral lipids, characterized by transmission electron microscopy and Nanoparticle Tracking Analysis. These liposomes, combined with plasmid DNA, formed lipoplexes used to transfect Hek-293 FT cells, achieving up to 40% transfection efficiency without cytotoxicity in the mixture of CholCadLys and CholCad. This novel CL demonstrates potential as an efficient, safe, and cost-effective gene transfer system, facilitating further development in gene therapy.

GREEN SYNTHESIS OF TIO2 USING ALOE VERA FOR PHOTODEGRADATION IN SASIRANGAN WASTE

Green synthesis of TiO2 has been successfully carried out using aloe vera. Aloe vera extract was mixed with TiCl4 while heated to obtain TiO2 powder. The FTIR spectrum showed a peak at 487.67 cm-¹ corresponding to the Ti-O-Ti functional group, which indicates the formation of TiO2 particles. The XRD results showed that the TiO2 crystals were in the anatase phase. SEM images show that the particles tend to be spherical in shape as in the anatase phase. With the Scherer equation, the size of the TiO2 crystal yielded was around 2.3 nm in diameter. The UV-vis spectrophotometer results showed the blue shift of absorption peak at 368 nm or band gap energy of 3.37 eV. A thin layer of TiO2 was made by using the slip casting method. These thin films were applied to methylene blue and sasirangan waste samples for photodegradation tests. The exposure times used were 15, 30, 45, 60, and 75 minutes. The results showed photodegradation of 38.9 % and 4.5 %, respectively, for methylene blue and sasirangan waste.

Structural and Viscoelastic Properties of Bacterial Cellulose Composites: Implications for Prosthetics.

This study investigates the morphological, mechanical, and viscoelastic properties of bacterial cellulose (BC) hydrogels synthesized by the microbial consortium Medusomyces gisevii. BC gel films were produced under static (S) or bioreactor (BioR) conditions. Additionally, an anisotropic sandwich-like composite BC film was developed and tested, consisting of a rehydrated (S-RDH) BC film synthesized under static conditions, placed between two BioR-derived BC layers. Sample characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), rheometry, and uniaxial stretching tests. To our knowledge, this is the first study to combine uniaxial and rheological tests for BC gels. AFM and SEM revealed that the organization of BC fibrils (80±20 nm in diameter) was similar to that of collagen fibers (96±31 nm) found in human dura mater, suggesting potential implications for neurosurgical practice. Stretching tests demonstrated that the drying and rehydration of BC films resulted in a 2- to 8-fold increase in rigidity compared to other samples. This trend was consistent across both small and large deformations, regardless of direction. Mechanically, the composite (BioR+S-RDH) outperformed BC hydrogels synthesized under static and bioreactor conditions by approx. 26%. The composite material (BioR+S-RDH) exhibited greater anisotropy in the stretching tests compared to S-RDH, but less than the BioR-derived hydrogels, which had anisotropy coefficients ranging from 1.29 to 2.03. BioR+S-RDH also demonstrated the most consistent viscoelastic behavior, indicating its suitability for withstanding shear stress and potential use in prosthetic applications. These findings should provide opportunities for further research and medical applications.

Utilization of waste biomass to produce SiO2/SiC nanowires with efficient electromagnetic wave absorption performance

Silicon carbide nanowires are widely used as highly efficient materials for absorbing electromagnetic waves (EMWs) owing to their wide bandgap and strong dielectric loss properties. In this study, SiO2/SiCnw is synthesized via a straightforward and environmentally friendly chemical vapor deposition technique, with coffee husk biochar as the growth template, at temperatures ranging from 1300 ℃ to 1600 ℃. The results indicate that higher reaction temperatures promote the growth of SiO2/SiCnw. The obtained SiO2/SiCnw is a nanostructure material composed of a large amount of SiO2–SiC mixture, and SiO2 coats the surface of SiC nanowires, each ranging from 30 to 200 nm in diameter. The SiO2/SiCnw prepared at 1600 ℃ exhibits the best EMW absorption performance. At a thickness of 3.3 mm and a frequency of 6.3 GHz, SiO2/SiCnw 1600 achieves the optimal reflection loss of − 50.40 dB and a maximum effective absorption bandwidth of 4.52 GHz. Overall, this study provides a broad and economical carbon source for efficient electromagnetic wave absorptive materials and a high-value recycling pathway for waste biomass.

Microfluidic Study of Application of Nanosuspension with Aluminum Oxide Nanofibers to Enhance Oil Recovery Factor During Reservoir Flooding

The paper presents the results of a comparative microfluidic study of the oil displacement process from a microfluidic chip simulating rock. Suspensions of spherical nanoparticles of silicon oxide (22 nm) and aluminum oxide (11 nm), as well as aluminum oxide nanofibers (8.7 nm in diameter and with an aspect ratio of 58), were used as displacing liquids. The nanofibers represent a unique new-generation crystalline material with a high aspect ratio. This work presents the first consideration of the use of aluminum oxide nanofibers as an additive for enhanced oil recovery. The comparative analysis has demonstrated that the addition of nanofibers can markedly enhance the oil recovery factor relative to the addition of spherical nanoparticles, other things being equal. Thus, in particular, it was demonstrated that the addition of nanofibers into the system allows for the greatest enhancement of the oil recovery factor, reaching a value of 25%, whereas the addition of spherical nanoparticles results in a maximum increment of approximately 10%. This is due to the fact that nanofiber additives have a tenfold stronger effect on the viscosity of nanosuspensions compared to similar additives of spherical particles. Nanosuspensions of aluminum oxide nanofibers exhibit non-Newtonian behavior at low concentrations. This opens the possibility of their extensive use in enhanced oil recovery.

Balloon Baseline Stratospheric Aerosol Profiles (B2SAP)—Perturbations in the Southern Hemisphere, 2019–2022

AbstractVolcanic and pyrocumulonimbus (pyroCB) injections into the stratosphere perturb the aerosol layer and can have important radiative and chemical impacts on timescales spanning from months to several years. Repeated in situ balloon‐borne measurements of aerosol size and number concentration (>140 nm in diameter), ozone, water vapor, and atmospheric state variables made at midlatitudes in the southern hemisphere (SH) since 2019 enable us to better characterize such events. We use this record and coincident lidar extinction profiles to study several moderate to large stratospheric perturbations in the SH between 2019 and 2022 in detail, including the Australian New Year Super Outbreak (ANYSO) pyroCB in 2020. Median vertical profiles of aerosol number concentration, effective radius, and surface area in SH midlatitudes are also compared with those recorded in Northern Hemisphere midlatitudes under baseline conditions using an identical payload. These data depict the variability in stratospheric aerosol properties in the SH midlatitudes during this period and provide a benchmark for global sectional aerosol models. They reveal that sulfate particle size distributions under baseline conditions and in volcanic plumes are relatively well represented in the Community Earth System Model—Community Aerosol Radiation Model for Atmospheres (CESM‐CARMA), but more observations of biomass burning plumes are needed to improve model skill in simulating pyroCB. Comparisons between in situ and lidar observations also highlight a need for more observations of aerosol composition and refractive index in both fresh and aging biomass burning plumes.

Adaptive Synthesis, Supramolecular Behavior, and Biological Properties of Amphiphilic Carbosilane-Phosphonium Dendrons with Tunable Structure.

Here, we present a modular synthesis as well as physicochemical and biological evaluation of a new series of amphiphilic dendrons carrying triphenylphosphonium groups at their periphery. Within the series, the size and mutual balance of lipophilic and hydrophilic domains are systematically varied, changing the dendron shape from cylindrical to conical. In physiological solution, the dendrons exhibit very low critical micelle concentrations (2.6-4.9 μM) and form stable and uniform micelles 6-12 nm in diameter, depending on dendron shape; the results correlate well with molecular dynamics simulations. The compounds show relatively high cytotoxicity (IC50 1.2-21.0 μM) associated with micelle formation and inversely related to the size of assembled particles. Depending on their shape, the dendrons show promising results in terms of dendriplex formation and antibacterial activity. In addition to simple amphiphilic dendrons, a fluorescently labeled analogue was also prepared and utilized as an additive visualizing the dendron's cellular uptake.

Physical Isolation of Single Protein Molecules within Well‐Defined Coordination Cages to Enhance Their Stability

Encapsulation of a single protein within a confined space can lead to distinct properties compared to bulk solutions, but controlling the number of encapsulated proteins and their environment remains challenging. This study demonstrates the encapsulation of single proteins within well‐defined, tunable cavities of self‐assembled coordination cages, thereby enhancing protein stability. Within uniform cavities of size‐tunable coordination cages, 15 different proteins of varying sizes (3‐6 nm in diameter) and properties (e.g., isoelectric points and hydrophobicity) were successfully confined. Various analytical techniques confirmed that the proteins maintained their secondary structures and enzymatic activities under denaturing conditions such as exposure to organic solvents, heat, and buffers. These findings suggest that such coordination cages have the potential to serve as synthetic hosts for precisely controlling protein functions within their customizable cavities.

Physical Isolation of Single Protein Molecules within Well-Defined Coordination Cages to Enhance Their Stability.

Encapsulation of a single protein within a confined space can lead to distinct properties compared to bulk solutions, but controlling the number of encapsulated proteins and their environment remains challenging. This study demonstrates the encapsulation of single proteins within well-defined, tunable cavities of self-assembled coordination cages, thereby enhancing protein stability. Within uniform cavities of size-tunable coordination cages, 15 different proteins of varying sizes (3-6 nm in diameter) and properties (e.g., isoelectric points and hydrophobicity) were successfully confined. Various analytical techniques confirmed that the proteins maintained their secondary structures and enzymatic activities under denaturing conditions such as exposure to organic solvents, heat, and buffers. These findings suggest that such coordination cages have the potential to serve as synthetic hosts for precisely controlling protein functions within their customizable cavities.

Preparation of Phosphorus/Hollow Silica Microsphere Modified Polyacrylonitrile-Based Carbon Fiber Composites and Their Thermal Insulation and Flame Retardant Properties

Since thermal insulation materials with a single function cannot satisfy the increasing requirements for complex usage, the combination of thermal insulation with flame retardancy is desirable in multiple applications. Herein, phosphorous-containing flame retardant modifier (5.0 wt.%, 9.0 wt.%, and 13.0 wt.%) and hollow silica microsphere (130 nm of diameter) were composited with polyacrylonitrile-based carbon nanofibers via electrospinning technique. Electrospun phosphorous/silica/carbon nanofibers (P/HSM/CF) exhibited a uniform and clear fibrous structure (508, 170, and 1550 nm of average fiber diameter) with modified uniform and complete spherical silica. Reduced thermal conductivity (39.9–41.2 mW/m/K) and enhanced limiting oxygen index (29.5–33.5%) were achieved, enabling fire protection grade of fiber membrane from UL-94 V-1 grade to UL-94 V-0 grade efficiently. Moreover, favorable tensile strength (8.64–9.27 MPa) and elongation at break (43.28–48.54%) were obtained, presenting expected applications in structural components. The findings of this work provided a valuable reference for the fabrication of carbon nanofiber-based thermal insulation materials with excellent flame retardant and mechanical properties.

In vitro characteristics of purified recombinant hepatitis C virus core protein

In our previous study, we established a method for purifying bacterially expressed HCV core 1–164 under non-denaturing conditions. In the present study, we elucidated the characteristics of the purified core. The purified HCV core exhibited a notable affinity for HCV RNA, with a Kd of 3 nM, as determined by a filter binding assay. Electron microscopy analysis revealed that the purified HCV core self-assembled with RNA into spherical structures approximately 50 nm in diameter. Additionally, we demonstrated the direct binding of the purified HCV core to the purified endoplasmic reticulum (ER). Moreover, lipid strip assays revealed specific binding of the purified HCV core to specific phospholipids, suggesting that the core plays a role in specific ER membrane domains. These studies reveal the biochemical characteristics of the HCV core that significantly advance our understanding of its role as a capsid protein in the viral lifecycle and pathogenesis.

Adipose-derived stem cell exosomal miR-21-5p enhances angiogenesis in endothelial progenitor cells to promote bone repair via the NOTCH1/DLL4/VEGFA signaling pathway

BackgroundAngiogenesis is essential for repairing critical-sized bone defects. Although adipose-derived stem cell (ADSC)-derived exosomes have been shown to enhance the angiogenesis of endothelial progenitor cells (EPCs), the underlying mechanisms remain unclear. This study aims to explore the effects and mechanisms of ADSC-derived exosomes in enhancing bone repair by promoting EPC angiogenesis.MethodsTransmission electron microscopy, nanoparticle tracking analysis, and Dil reagent kit were employed to identify ADSC-derived exosomes and their internalization by EPCs. Micro-CT analysis, H&E staining, and Masson staining were used to assess bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N), as well as the pathological changes and fibrosis at defect sites. Cell viability, migration, invasion, and tube formation of EPCs were evaluated using CCK-8, wound healing, Transwell, and tube formation assays. Immunohistochemical staining, RT-PCR, and Western blotting were utilized to measure the gene and protein expression of markers such as CD31, VEGFA, OCN, RUNX2, NOTCH1, and DLL4. Gene sequencing and bioinformatics analyses were conducted to identify the most highly expressed miRNA in exosomes, while miRDB and dual-luciferase reporter assays were used to explore the interaction between miR-21-5p and NOTCH1.ResultsThe ADSC-derived exosomes, averaging 126 nm in diameter, were internalized by EPCs. In vivo, these exosomes promoted new bone formation, increased BMD, BV/TV, Tb.Th, and Tb.N, reduced pathological damage to cranial defect tissues, enhanced vascular and bone tissue regeneration, and upregulated OCN and RUNX2 expression. In vitro, ADSC-derived exosomes enhanced EPC viability, migration, invasion, and tube formation. Both in vivo and in vitro experiments demonstrated that ADSC-derived exosomes upregulated CD31 and VEGFA expression. miR-21-5p, the most highly expressed miRNA in ADSC-derived exosomes, was found to target NOTCH1. Overexpression of miR-21-5p in these exosomes facilitated EPC migration, tube formation, and VEGFA expression while downregulating NOTCH1 and DLL4 expression. Inhibition of miR-21-5p produced opposite effects on EPCs.ConclusionsThese findings indicate that miR-21-5p in ADSC-derived exosomes promotes angiogenesis in EPCs to accelerate bone repair by targeting the NOTCH1/DLL4/VEGFA signaling pathway, offering a potential therapeutic strategy for bone defect treatment.Graphical

Quantitative Examination and Mechanistic Insights of Polymer Chain Conformation Confined in Nanopores by Time-Resolved Fluorescence Resonance Energy Transfer.

The conformational studies of polymers confined at the nanoscale remain challenging and controversial due to the limitations of characterization techniques. In this study, we utilized the high sensitivity of time-resolved fluorescence resonance energy transfer (trFRET) and a site-specific dye-labeling strategy to characterize the conformation of polymer chains confined in anodic aluminum oxide (AAO) nanopores. This strategy introduced a fluorescent donor (carbazole) and acceptor (anthracene) at the center of poly(butyl methacrylate) (PBMA) chains grown by atom transfer radical polymerization (ATRP). By quantitatively analyzing fluorescence decay through the Förster mechanism and the Drake-Klafter-Levitz (DKL) formalism, we can determine both the energy transfer efficiency and the spatial distribution of the dyes. This analysis revealed that the PBMA chains, with a molecular weight of 40 kDa, maintained their bulk-like conformation even when confined within nanopores as small as 10 nm in diameter. This study is the first to demonstrate the use of trFRET for investigating chain conformation in confined polymer systems, which can be generalized to other polymer types and polymer topologies in different confined geometries.