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Particle atomic layer deposition
摘要： The functionalization of fine primary particles by atomic layer deposition (particle ALD) provides for nearly perfect nanothick films to be deposited conformally on both external and internal particle surfaces, including nanoparticle surfaces. Film thickness is easily controlled from several angstroms to nanometers by the number of self-limiting surface reactions that are carried out sequentially. Films can be continuous or semi-continuous. This review starts with a short early history of particle ALD. The discussion includes agitated reactor processing, both atomic and molecular layer deposition (MLD), coating of both inorganic and polymer particles, nanoparticles, and nanotubes. A number of applications are presented, and a path forward, including likely near-term commercial products, is given.
关键词： Coating,Particle ALD,Nanoparticle,Nanolayers,Atomic layer deposition
更新于2025-09-23 15:22:29
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pH-sensitive fluorescent organic nanoparticles: Off-on fluorescent detection of furfural in transformer oil
摘要： Furfural content is considered as index to estimate transformer remnant life. Therefore, low cost, highly sensitive methods for determination of furfural are highly desirable. In the present work, we describe a new strategy for furfural detection by tracing the 'off-on' fluorescence signals of fluorescent organic nanoparticles (FONPs). Significant H+-dependent emission characteristics in aprotic organic solvent was found for our synthesized poly(DOPA)-FONPs. The fluorescence of poly(DOPA)-FONPs can be quickly quenched by hydroxylamine hydrochloride. Furfural can react with hydroxylamine hydrochloride to produce furan-2-carbaldehyde oxime and release proton in a 1:1 proportion. Then H+ produced by the reaction caused the fluorescence intensity at 520 nm to increase as a linear function of furfural concentrations. Under the optimum conditions, the linear working concentration range was found to be 0.01~30 mg L-1 and the LOD for the determination of furfural was 0.0015 mg L-1. The proposed method was used to determine furfural in transformer oil samples satisfactorily, providing a convenient alternative to conventional techniques.
关键词： pH-sensitivity,Transformer oil,Fluorescent assay,Fluorescent organic nanoparticle,Detection of furfural
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Hydrogen Evolution with TiO <sub/>2</sub> -TiN Nanoparticle Composites
摘要： Metal nitrides have potential in energy applications due to their physical and optical properties. Nanoparticle composites of titanium nitride (TiN) and titanium dioxide (TiO2) were investigated for their photocatalytic hydrogen (H2) activity via methanol reformation. Physical mixing of the nanoparticulate TiO2 and TiN was employed to prevent the oxy-nitride formation and particle aggregation observed in thermal preparations. This convenient combination of TiO2 and TiN demonstrated a substantial synergistic effect with enhanced activity (9.4 μmol/h TiO2-TiN vs 1.8 μmol/h TiO2) under combined UV/Vis light. Irradiation under only UV light resulted in a similar enhancement factor compared to using combined UV/Vis light, demonstrating that the enhanced activity of the composites occurs essentially for UV-driven photocatalysis. No activity/enhancement was observed with only visible light irradiation, however, minor enhancement was observed when switching between UV and UV/Vis irradiation, suggesting a contribution from the TiN plasmon. We propose that the plasmonic contribution is dependent on the band gap excitation of TiO2, which reduces the degree of band bending at the TiO2/TiN interface. This promotes the migration of hot electrons from TiN away from the TiO2/TiN interface to be used for H2 evolution.
关键词： TiO2-TiN Nanoparticle Composites,Plasmonics,Optical,Magnetic,and Hybrid Materials,Photocatalytic Hydrogen Evolution
更新于2025-09-23 15:22:29
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Physiologically Stable Hydrophilic C60 Nanoparticles for Photodynamic Therapy
摘要： Hydrophilic C60 nanoparticles that are highly stable in living systems were prepared with sugammadex, an anionic γ-cyclodextrin derivative, via a simple procedure for use in biological applications. The prepared C60/sugammadex nanoparticles showed outstanding stability under physiological conditions and even in much harsher conditions. The sugammadex interacted with C60 nanoparticles through strong host-guest interactions on the particle surface, producing a negatively charged layer on the surface of nanoparticles, which contributed to the high stability of the nanoparticles. In addition, the nanoparticles were highly stable in the presence of singly charged cations which are present in abundance in living systems. The stable C60/sugammadex nanoparticles showed a significantly different biological behavior compared to less stable C60 nanoparticles after intravenous administration. Most of the C60 particles accumulated and remained in organs of the reticuloendothelial system (RES) after administration, which are susceptible to forming aggregates in physiological conditions. On the other hand, the C60/sugammadex nanoparticles showed a completely different biological behavior, i.e. longer blood circulation, low RES uptake and elimination with time from organs. The photodynamic activity of C60/sugammadex nanoparticles was evaluated both in vitro and in vivo, and an outstanding antitumor effect was achieved based on the generation of reactive oxygen species under light irradiation. We envision that such stable C60 nanoparticles would be a desirable approach for extending the biological applications of these materials and the precise evaluation of C60 activity in living systems.
关键词： nanoparticle,biodistribution,in vivo aggregation,photodynamic therapy,fullerene
更新于2025-09-23 15:22:29
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An Enzyme-Free MicroRNA Assay Based-on Fluorescence Counting of Click Chemical Ligation-Illuminated Magnetic Nanoparticles with Total Internal Reflection Fluorescence Microscopy
摘要： MicroRNAs (miRNAs) have been considered as promising cancer biomarkers. However, the simple but sensitive detection of low levels of miRNAs in biological samples still remains challenging. Herein, we wish to report an entirely enzyme-free, simple and highly sensitive miRNA assay based on the counting of cycling click chemical ligation (3CL)-illuminated fluorescent magnetic nanoparticles (MNPs) with a total internal reflection fluorescence microscopy (TIRFM). In this strategy, each miRNA molecule can trigger many cycles of click chemical ligation reactions to produce plentiful ligated oligonucleotides (ODNs) with both 5’-biotin and 3’-fluorophore, resulting in efficient signal amplification. It is worth noting that only the ligated ODNs can bring fluorophores onto streptavidin-functionalized MNPs (STV-MNPs). Notably, merely 10 fluorescent molecules on each 50 nm MNP can make it bright enough to be clearly visualized by the TIRFM, which can significantly improve the detection sensitivity for miRNA. Through fluorescence counting of individual MNPs and integrating their fluorescence intensities, the amount of target miRNA can be quantitatively determined. This miRNA assay can be accomplished in a mix-and-read manner just by simply mixing the enzyme-free 3CL reaction system with the MNPs before TIRFM imaging, which avoids tedious immobilization, washing and purification steps. Despite the extremely simple operation, this strategy exhibits high sensitivity with a quite low detection limit of 50 fM target miRNA as well as high specificity to well discriminate miRNA sequences with a single-base variation. Furthermore, the applicability of this method in real biological samples is also verified through the accurate detection of miRNA target in cancer cells.
关键词： click chemistry,microRNA,TIRFM,magnetic nanoparticle,fluorescence counting
更新于2025-09-23 15:21:21
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Quantification of DNA by a Thermal-Durable Biosensor Modified with Conductive Poly(3,4-ethylenedioxythiophene)
摘要： The general clinical procedure for viral DNA detection or gene mutation diagnosis following polymerase chain reaction (PCR) often involves gel electrophoresis and DNA sequencing, which is usually time-consuming. In this study, we have proposed a facile strategy to construct a DNA biosensor, in which the platinum electrode was modified with a dual-film of electrochemically synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) resulting in immobilized gold nanoparticles, with the gold nanoparticles easily immobilized in a uniform distribution. The DNA probe labeled with a SH group was then assembled to the fabricated electrode and employed to capture the target DNA based on the complementary sequence. The hybridization efficiency was evaluated with differential pulse voltammetry (DPV) in the presence of daunorubicin hydrochloride. Our results demonstrated that the peak current in DPV exhibited a linear correlation the concentration of target DNA that was complementary to the probe DNA. Moreover, the electrode could be reused by heating denaturation and re-hybridization, which only brought slight signal decay. In addition, the addition of the oxidized form of nicotinamide adenine dinucleotide (NAD+) could dramatically enhance the sensitivity by more than 5.45-fold, and the limit-of-detection reached about 100 pM.
关键词： poly(3,4-ethylenedioxythiophene),gold nanoparticle,electron transfer mediate,DNA biosensor
更新于2025-09-23 15:21:21
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Total Internal Reflection-based Extinction Spectroscopy of Single Nanoparticles
摘要： Here we report a reflection-mode total internal reflection microscopy (TIRM) to measure the extinction spectrum of individual dielectric, plasmonic or light-absorbing nanoparticle, and to differentiate absorption and scattering components from the total optical output. These capabilities were enabled via illuminating the sample with evanescent wave of which the lightpath length was comparable with the size of single nanoparticles, leading to a dramatically improved reflectance change (ΔI/I0) up to tens of percent. It was further found that scattering and absorption of light contributed to bright and dark centroids, respectively, in the optical patterns of single nanoparticles, allowing for distinguishing scattering and absorption components from the extinction spectrum by the use of an appropriate image processing method. In addition, wide-field feature of TIRM enabled the studies on tens of nanoparticles simultaneously with gentle illumination. The present work not only provides a promising and complementary tool for understanding the light-matter interactions at single nanoparticle level, but also expands the applicable scope of total internal reflection-based spectroscopy and microscopy.
关键词： total internal reflection,single nanoparticle spectroscopy,extinction spectroscopy
更新于2025-09-23 15:21:21
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Utilizing embedded ultra-small Pt nanoparticles as charge trapping layer in flashristor memory cells
摘要： In this study, a methodology for producing highly controlled and uniformly dispersed metal nanoparticles were developed by atomic layer deposition (ALD) technique. All-ALD grown thin film flash memory (TFFM) cells and their applications were demonstrated with ultra-small platinum nanoparticles (Pt-NPs) as charge trapping layer and control tunnel oxide layer. The ultra-small Pt-NPs possessed sizes ranging from 2.3 to 2.6 nm and particle densities of about 2.5 × 1013 cm–b. The effect of Pt-NPs embedded on the storage layer for charging was investigated. The charging effect of ultra-small Pt-NPs the storage layer was observed using the electrical characteristics of TFFM. The Pt-NPs were observed by a high-resolution scanning electron microscopy (HR-SEM). The memory effect was manifested by hysteresis in the IDS-VDS and IDS-VGS curves. The charge storage capacity of the TFFM cells demonstrated that ALD-grown Pt-NPs in conjunction with ZnO layer can be considered as a promising candidate for memory devices. Moreover, ZnO TFFM showed a ION/IOFF ratio of up to 52 orders of magnitude ?a/b – Vgs curve. Fabricated TFFMs exhibited clear pinch-off and show n-type field effect transistor (FET) behavior. The role of atomic-scale controlled Pt-NPs for improvement of devices were also discussed and they indicated that ALD-grown Pt-NPs can be utilized in nanoscale electronic devices as alternative quantum dot structures.
关键词： ZnO,Thin film flash memory,Pt nanoparticle,Atomic layer deposition,Memristor
更新于2025-09-23 15:21:21
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Anomalous dichroism of cellulose nanowhisker embedded
摘要： While natural nanoparticles are currently being investigated in a wide range of applications due to their compelling strong potential, they have yet to be employed for practical engineering material systems. Here, we demonstrate a dichroic nanocomposite film that shows outstanding optical properties by introducing cellulose nanowhiskers (CNWs) into PVA iodine complex. CNWs were isolated via acid hydrolysis and the nanocomposite film was elongated and dyed with iodine. The significantly reduced extension and treatment time of iodine were applied for the alignment of iodine and PVA molecules in the film. The results revealed that the degree of polarization and transmittance were enhanced as the draw ratio and the content of the CNWs increased. We expect that this material system can offer a new pathway for designing and processing more advanced engineering materials with high performances by using various natural biomaterials.
关键词： nanocomposites,nanowhisker,cellulose,nanoparticle
更新于2025-09-23 15:21:21
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Liquid-Cell Scanning Transmission Electron Microscopy and Fluorescence Correlation Spectroscopy of DNA-Directed Gold Nanoparticle Assemblies
摘要： In the use of solution-based 3D nanoarchitectures for optics, drug delivery, and cancer treatment, the precise nanoparticle architecture morphologies, architecture sizes, interparticle distances, and the assembly stability are all critical to their functionality. 3D nanoparticle architectures in solution are difficult to characterize, as few techniques can provide individualized information on interparticle spacing (defined by linkage molecule), nanoparticle assembly size, morphology, and identification of false aggregation. Bulk characterization techniques, including small angle x-ray scattering, can provide architecture sizes, though they are unable to precisely measure differences within interparticle spacings for individual architectures and can falsely measure assemblies caused by non-linkage grouped nanoparticles. Two solution-based characterization techniques were used to determine which assembly type and linkage length would produce the fastest assembly rate for large DNA-directed gold nanoparticle assemblies. In-situ liquid-cell scanning transmission electron microscopy (STEM), measured interparticle spacings between DNA-functionalized nanoparticles, and fluorescence correlation spectroscopy provided the bulk volume fraction of large and small assemblies for nanoparticle architectures that were assembled using two different types: (1) the hybrid assemblies join two complementary single-stranded DNA linkages, and (2) the bridged assemblies are comprised of single-stranded DNA (bridging component) that is double the length of two different complementary single-stranded DNA-functionalized gold nanoparticles (Fig. 1). Assembly times were tested at 24-hour intervals over 3 days. Statistics derived from the in-situ liquid-cell STEM images provided data for interparticle distance measurements, which identified the fraction of nanoparticles within the images acquired that were at the expected double-stranded DNA-binding distance of the linkages (varied in three distances for each of the two different architectures). In general, longer linkage lengths assembled in the shortest amount of time. The bridged assemblies formed fewer large architectures at 24-hours but ultimately assembled a greater fraction of nanoparticles, which was due to the longer functionalized DNA lengths for individual nanoparticles. Fluorescence correlation spectroscopy provided a bulk average of the gold nanoparticle assembly sizes over time, which supported the conclusions drawn from the in-situ liquid-cell STEM data. The microscopy provided sub-2 nanometer precision in the interparticle distances between gold nanoparticles in a solution environment. This coupled microscopy and spectroscopy characterization approach can provide more detailed information than bulk characterization methods.
关键词： gold,nanoparticle,DNA,FCS,assembly,liquid-cell TEM
更新于2025-09-23 15:21:21