High-Throughput Identification of Single Nanoparticles via Electrochemically Assisted High-Resolution Plasmonic Scattering Interferometric Microscopy.

The identification of nanoparticles within heterogeneous mixtures poses significant challenges due to the similarity in physical properties among different nanomaterials. Here, we present electrochemically assisted high-resolution plasmonic scattering interferometric microscopy (HR-PSIM). This technique allows for the high-throughput identification of nanoparticles by accurately measuring the refractive index of individual nanoparticles without interference from background signals. Through elimination of parabolic scattering interference and employing electrochemical modulation, HR-PSIM demonstrates high spatial resolution and stability against background noise, enabling the differentiation of nanoparticles with closely matched refractive indices, such as Au and Ag nanoparticles. The efficacy of this method is demonstrated through its application in real-time, label-free imaging of nanoparticle electrochemical activity, providing a platform for the precise and high-throughput characterization of nanomaterials. The robustness of our approach against electrochemical interference and its high spatial resolution mark a significant advancement in the field of nanomaterial analysis, promising wide-ranging applications in nanoparticle research and beyond.

Deep-Learning Driven, High-Precision Plasmonic Scattering Interferometry for Single-Particle Identification.

Label-free probing of the material composition of (bio)nano-objects directly in solution at the single-particle level is crucial in various fields, including colloid analysis and medical diagnostics. However, it remains challenging to decipher the constituents of heterogeneous mixtures of nano-objects with high sensitivity and resolution. Here, we present deep-learning plasmonic scattering interferometric microscopy, which is capable of identifying the composition of nanoparticles automatically with high throughput at the single-particle level. By employing deep learning to decode the quantitative relationship between the interferometric scattering patterns of nanoparticles and their intrinsic material properties, this technique is capable of high-throughput, label-free identification of diverse nanoparticle types. We demonstrate its versatility in analyzing dynamic surface chemical reactions on single nanoparticles, revealing its potential as a universal platform for nanoparticle imaging and reaction analysis. This technique not only streamlines the process of nanoparticle characterization, but also proposes a methodology for a deeper understanding of nanoscale dynamics, holding great potential for addressing extensive fundamental questions in nanoscience and nanotechnology.

Towards high photoresponse of perovskite nanowire/copper phthalocyanine heterostructured photodetector.

One-dimensional nanowire structures composed of perovskite are widely recognized for their exceptional optoelectronic performance and mechanical properties, making them a popular area of investigation in photodetection research. In this work, a perovskite nanowire/copper phthalocyanine heterojunction-based photodetector was fabricated, which exhibits high photoresponse in the visible-near-infrared region. The incorporation of a heterojunction significantly enhanced the photoelectric performance. Specifically, the photoresponsivity and external quantum efficiency of the nanowire-based device were elevated from 58.5 A W-1and 1.35 × 104% to 84.5 A W-1and 1.97 × 104% at 532 nm, respectively. The enhanced photoresponse of the heterojunction device can be attributed to the unique microstructure of nanowire arrays. The wrapping of the nanowires by copper phthalocyanine forms heterojunctions with a larger dissociation area, which facilitated exciton dissociation and enhanced device performance. This work provides a promising example for optimizing the performance of nanowire devices.

Dynamic imaging of interfacial electrochemistry on single Ag nanowires by azimuth-modulated plasmonic scattering interferometry.

Direct visualization of surface chemical dynamics in solution is essential for understanding the mechanisms involved in nanocatalysis and electrochemistry; however, it is challenging to achieve high spatial and temporal resolution. Here, we present an azimuth-modulated plasmonic imaging technique capable of imaging dynamic interfacial changes. The method avoids strong interference from reflected light and consequently eliminates the parabolic-like interferometric patterns in the images, allowing for a 67-fold increase in the spatial resolution of plasmonic imaging. We demonstrate that this optical imaging approach enables comprehensive analyses of surface chemical dynamics and identification of previously unknown surface reaction heterogeneity by investigating electrochemical redox reactions over single silver nanowires as an example. This work provides a general strategy for high-resolution plasmonic imaging of surface electrochemical dynamics and other interfacial chemical reactions, complementing existing surface characterization methods.

Plasmonic Scattering Imaging of Surface-Bonded Nanoparticles at the Solution-Solid Interface.

Imaging nanoscale objects at interfaces is essential for revealing surface-tuned mechanisms in chemistry, physics, and life science. Plasmonic-based imaging, a label-free and surface-sensitive technique, has been widely used for studying the chemical and biological behavior of nanoscale objects at interfaces. However, direct imaging of surface-bonded nanoscale objects remains challenging due to uneven image backgrounds. Here, we present a new surface-bonded nanoscale object detection microscopy that eliminates strong background interference by reconstructing accurate scattering patterns at different positions. Our method effectively functions at low signal-to-background ratios, allowing for optical scattering detection of surface-bonded polystyrene nanoparticles and severe acute respiratory syndrome coronavirus 2 pseudovirus. It is also compatible with other imaging configurations, such as bright-field imaging. This technique complements existing methods for dynamic scattering imaging and broadens the applications of plasmonic imaging techniques for high-throughput sensing of surface-bonded nanoscale objects, enhancing our understanding of the properties, composition, and morphology of nanoparticles and surfaces at the nanoscale.

Thickness-ratio-dependent performances of broadband organic photodiodes based on a tin phthalocyanine/PTCDA heterojunction.

Employing a photosensitive donor/acceptor planar heterojunction (DA-PHJ) with complementary optical absorption as the active layer is one of the key strategies for realizing broad spectral organic photodiodes (BS-OPDs). To achieve superior optoelectronic performance, it is vital to optimize the thickness ratio of the donor layer to acceptor layer (the DA thickness ratio) in addition to the optoelectronic properties of the DA-PHJ materials. In this study, we realized a BS-OPD exploiting tin(II) phthalocyanine (SnPc)/3,4,9,10-perylenete-acarboxylic dianhydride (PTCDA) as the active layer and investigated the effect of the DA thickness ratio on the device performance. The results showed that the DA thickness ratio has a significant impact on the device performance, and an optimized DA thickness ratio of 30:20 was found. Upon the optimization of the DA thickness ratio, improvements of 187% in photoresponsivity and 144% in specific detectivity were achieved on average. Trap-free space-charge-limited photocarrier transport and balanced optical absorption over the wavelength range can be ascribed to the improved performance at the optimized DA thickness ratio. These results establish a solid photophysical foundation for improving the performance of BS-OPDs via thickness ratio optimization.

Ultranarrow-band filterless photodetectors based on CH3NH3PbClxBr3-xmixed-halide perovskite single crystals.

Narrow-band photodetectors based on halide perovskite have recently attracted significant attention due to their exceptional narrow-band detection performance and tunable absorption peaks covering a wide optical range. In this work, we report mixed-halide CH3NH3PbClxBr3-xsingle crystal-based photodetectors have been fabricated, where the Cl/Br ratios were varied (3:0, 10:1, 5:1, 1:1, 1:7, 1:14 and 0:3). Vertical and parallel structures devices were fabricated which exhibited ultranarrow spectral responses under bottom illumination, with a full-width at half-maximum less than 16 nm. The observed performance can be ascribed to the unique carrier generation and extraction mechanisms within the single crystal under short and long wavelength of illumination. These findings offer valuable insights into the development of narrow-band photodetectors that do not necessitate the use of filters and hold tremendous potential for a diverse array of applications.

Label-Free Optical Imaging of the Electron Transfer in Single Live Microbial Cells.

Measurement of electron transfer at the single-particle or -cell level is crucial to the in situ study of basic chemical and biological processes. However, it remains challenging to directly probe the microbial extracellular electron transfer process due to the weakness of signals and the lack of techniques. Here, we present a label-free and noninvasive imaging method that is able to measure the electron transfer in microbial cells. We measured the extracellular electron transfer processes by imaging the redox reaction of c-type outer membrane cytochromes in microbial cells using a plasmonic imaging technique, and obtained the electrochemical activity parameters (formal potential and number of electrons transferred) of multiple individual microbial cells, allowing for unveiling ample heterogeneities in electron transfer at the single-cell level. We anticipate that this method will contribute to the study of electron transfer in various biological and chemical processes.

In Situ Construction of Protective Films on Zn Metal Anodes via Natural Protein Additives Enabling High-Performance Zinc Ion Batteries.

The strong activity of water molecules causes a series of parasitic side reactions on Zn anodes in the aqueous electrolytes. Herein, we introduce silk fibroin (SF) as a multifunctional electrolyte additive for aqueous zinc-ion (Zn-ion) batteries. The secondary structure transformation of SF molecules from α-helices to random coils in the aqueous electrolytes allows them to break the hydrogen bond network among free water molecules and participate in Zn2+ ion solvation structure. The SF molecules released from the [Zn(H2O)4(SF)]2+ solvation sheath appear to be gradually adsorbed on the surface of Zn anodes and in situ form a hydrostable and self-healable protective film. This SF-based protective film not only shows strong Zn2+ ion affinity to promote homogeneous Zn deposition but also has good insulating behavior to suppress parasitic reactions. Benefiting from these multifunctional advantages, the cycle life of the Zn||Zn symmetric cells reaches over 1600 h in SF-containing ZnSO4 electrolytes. In addition, by adopting a potassium vanadate cathode, the full cell shows excellent cycling stability for 1000 cycles at 3 A g-1. The in situ construction of a protective film on the Zn anode from natural protein molecules provides an effective strategy to achieve high-performance Zn metal anodes for Zn-ion batteries.

Primary malignant pericardial mesothelioma with a survival of 2.5 years: a case report.

Background: Primary malignant pericardial mesothelioma (PMPM) is a highly malignant tumor originating in the pericardium serosum with clinical manifestations presenting as constrictive pericarditis, with pericardial tamponade and heart failure. Malignant pericardial mesothelioma is rare and has a poor prognosis, with an average survival time of 6-10 months. Case Description: Herein, we report the case of a 57-year-old female who developed chest tightness and panic for no obvious reason. She was diagnosed with tuberculous pericarditis via multiple examinations including positron emission tomography/computed tomography (PET/CT), pleural biochemical routine, tuberculin purified protein derivative (PPD) test, T cell spot (T-SPOT) test, and echocardiography, and was experienced intermittent relief after anti-tuberculosis treatment. On 21 July, 2020, pericardiectomy was performed due to poor therapeutic effect, and the postoperative pathological diagnosis was malignant mesothelioma. After discussing treatment plans and considering the prognosis, the patient opted for palliative care. Subsequently, her symptoms gradually worsened, with chest tightness, shortness of breath, palpitations at rest, frequent arrhythmias, heart failure, cardiogenic shock, and multiple plasma chamber effusions. This case showed that the most common misdiagnosis of PMPM is tuberculous pericarditis, which needs to be differentiated from pleural mesothelioma with pericardial metastasis. Conclusions: The diagnosis of PMPM is usually made by pathologic surgery or histopathological examination to determine the specific disease location. In addition, pericardiocentesis fluid exfoliation cytology, imaging and echocardiography can assist diagnosis. Due to the lack of effective treatment for PMPM, timely surgery and postoperative adjuvant chemotherapy are needed to improve the quality of life of patients and prolong their survival time.

Real-Time Plasmonic Imaging of the Compositional Evolution of Single Nanoparticles in Electrochemical Reactions.

Real-time probing of the compositional evolution of single nanoparticles during an electrochemical reaction is crucial for understanding the structure-performance relationship and rationally designing nanomaterials for desirable applications; however, it is consistently challenging to achieve high-throughput real-time tracking. Here, we present an optical imaging method, termed plasmonic scattering interferometry microscopy (PSIM), which is capable of imaging the compositional evolution of single nanoparticles during an aqueous electrochemical reaction in real time. By quantifying the plasmonic scattering interferometric pattern of nanoparticles, we establish the relationship between the pattern and composition of single nanoparticles. Using PSIM, we have successfully probed the compositional transformation dynamics of multiple individual nanoparticles during electrochemical reactions. PSIM could be used as a universal platform for exploring the compositional evolution of nanomaterials at the single-nanoparticle level and offers great potentials for addressing the extensive fundamental questions in nanoscience and nanotechnology.

Overexpression of bmp4, dazl, nanos3 and sycp2 in Hu Sheep Leydig Cells Using CRISPR/dcas9 System Promoted Male Germ Cell Related Gene Expression.

Male germ cells directly affect the reproduction of males; however, their accurate isolation and culture in vitro is extremely challenging, hindering the study of germ cell development and function. CRISPR/dcas9, as an efficient gene reprogramming system, has been verified to promote the transdifferentiation of pluripotent stem cells into male germ cells by editing target genes. In our research, we explored the expression pattern of the germ cell related genes bmp4, dazl,nanos3 and sycp2 in Hu sheep testicular development and constructed the overexpression model using the CRISPR/dcas9 system. The results indicated that four genes showed more expression in testis tissue than in other tissues, and that bmp4, dazl and sycp2 present higher expression levels in nine-month-old sheep testes than in three-month-olds, while nanos3 expressed the opposite trend (p < 0.05). In addition, the expression of four potential genes in spermatogenic cells was slightly different, but they were all expressed in sheep Leydig cells. To verify the potential roles of the four genes in the process of inducing differentiation of male germ cells, we performed cell transfection in vitro. We found that the expression of the germ cell related genes Prdm1, Prdm14, Mvh and Sox17 were significantly increased after the overexpression of the four genes in Leydig cells, and the co-transfection effect was the most significant (p < 0.05). Our results illustrate the crucial functions of bmp4, dazl, nanos3 and sycp2 in Hu sheep testis development and verified the effectiveness of the overexpression model that was constructed using the CRISPR/dcas9 system, which provided a basis for further male germ cell differentiation in vitro.

Label-Free Probing of Molecule Binding Kinetics Using Single-Particle Interferometric Imaging.

Probing molecular interactions is critical for screening drugs, detecting pollutants, and understanding biological processes at the molecular level, but these interactions are difficult to detect, especially for small molecules. A label-free optical imaging technology that can detect molecule binding kinetics is presented, in which free-moving particles are driven into oscillations with an alternating electrical field and the interferometric scattering patterns of the particles are imaged via an optical imaging method. By tracking the charge-sensitive variations in the oscillation amplitude with sub-nanometer precision, the small molecules and metal ions binding to the surface as well as protein-protein binding kinetics were measured. The capability of the label-free measurement of molecular interactions can provide a promising platform for screening small-molecule drugs, probing conformational changes in proteins, and detecting environmental pollutants.

The characteristics of atmospheric particles and metal elements during winter in Beijing: Size distribution, source analysis, and environmental risk assessment.

In order to investigate the pollution characteristics of size-segregated particles and metal elements (MEs) after the Chinese Air Pollution Prevention Action Plan was released in 2013, an intensive field campaign was conducted in the suburban area of Chaoyang District, Beijing in winter 2016. The size distributions of particle mass concentrations were bimodal, with the first peak in the fine fraction (0.4-2.1 µm) and the second peak in the coarse fraction (3.3-5.8 µm). Moreover, the proportion of fine particles increased and the proportion of coarse particles decreased as the pollution level was more elevated. It was found that the composition of coarse particles is as important as that of fine particles when pollution of aerosol metals in the atmosphere in 2016 were compared to 2013. In addition, according to the size distribution characteristics, 23 MEs were divided into three groups: (a) Fe, Co, Sr, Al, Ti, Ba, and U, which concentrated in coarse mode; (b) Zn, As, Cd, Tl, and Pb, which concentrated in fine mode; and (c) Na, K, Be, V, Cr, Mn, Ni, Cu, Mo, Ag, and Sn, showing bimodal distribution. Under clean air, slight pollution and moderate pollution conditions, most elements maintained their original size distributions, while under severe pollution, the unimodal distributions of most MEs became bimodal distributions. The factors analysis combined with size distributions indicated that Na, Zn, Mo, Ag, Cd, and Tl, showing the moderate to severe contamination on environment, were significantly influenced by diffuse regional emissions or anthropogenic source emissions (vehicle exhaust emissions and combustion process). The environmental risk assessment revealed that the heavy metal loading in the atmospheric particles collected had a high potential for ecological risk to the environment during sampling period because of the high contribution of Cd, Tl, Zn and Pb.

Plasmonic probing of the adhesion strength of single microbial cells.

Probing the binding between a microbe and surface is critical for understanding biofilm formation processes, developing biosensors, and designing biomaterials, but it remains a challenge. Here, we demonstrate a method to measure the interfacial forces of bacteria attached to the surface. We tracked the intrinsic fluctuations of individual bacterial cells using an interferometric plasmonic imaging technique. Unlike the existing methods, this approach determined the potential energy profile and quantified the adhesion strength of single cells by analyzing the fluctuations. This method provides insights into biofilm formation and can also serve as a promising platform for investigating biological entity/surface interactions, such as pathogenicity, microbial cell capture and detection, and antimicrobial interface screening.

Pollution sources of atmospheric fine particles and secondary aerosol characteristics in Beijing.

To investigate the secondary formation and pollution sources of atmospheric particles in urban Beijing, PM2.5 and its chemical components were collected and determined by URG-9000D ambient ion monitor (AIM) from March 2016 to January 2017. Among water-soluble ions (WSIs), NO3-, SO42- and NH4+ (SNA) had the largest proportion (77.8%) with the total concentration of 23.8 µg/m3. Moreover, as fine particle pollution worsened, the NO3-, SO42- and NH4+ concentrations increased basically, which revealed that secondary aerosols were the main cause of particle pollution in Beijing. Furthermore, the particle neutralization ratio (1.1), the ammonia to sulfate molar ratio (3.4) and the nitrate to sulfate molar ratio (2.2) showed that secondary aerosols are under ammonium-rich conditions with the main chemical forms of NH4NO3 and (NH4)2SO4, and vehicle emission could be the main anthropogenic source of secondary aerosols in Beijing. Source analysis further indicated that secondary aerosols, solid fuel combustion, dust and marine aerosol were the principal pollution sources of PM2.5, accounting for about 46.1%, 22.4% and 13.0%, respectively, and Inner Mongolia and Hebei Provinces could be considered as the main potential sources of PM2.5 in urban Beijing. In addition, secondary formation process was closely related with gaseous precursor emission amounts (SO2, NO2, NH3 and HONO), atmospheric ozone concentration (O3), meteorological conditions (temperature and relative humidity) and particle components. Sensitive analysis of the thermodynamic equilibrium model (ISORROPIA II) revealed that controlling total nitrate (TN) is the effective measure to mitigate fine particle pollution in Beijing.

Approaches for identifying PM2.5 source types and source areas at a remote background site of South China in spring.

The receptor model is an effectively and widely used tool for analyzing the source of PM2.5, and its development and improvement have always been focused and challenged. In this study, approaches of source analysis is applied and compared. The PM2.5 samples were collected in spring of 2015 at a remote background site of Weizhou, South China and were analyzed for water-soluble ions, trace metals, and sugars. The 28 measurement species were introduced into the positive matrix factorization (PMF) and a non-negative matrix factorization (NMF) model for inter-comparison of PM2.5 prediction. Results showed that the NMF model is a more robust tool to identify source types and source apportionment in the case of a small sample size (n = 31). In NMF, four source variants were obtained as dust (15.6%), biomass combustion (11.8%), secondary formation (17.6%), and coal combustion (54.9%), corresponding to four main source areas. These were Southeast Asia, South China Sea, Taiwan Strait, as well as Pearl River Delta, respectively. The areas were distinguished based on hybrid receptor models, potential source contribution function (PSCF) and concentration weighted trajectory (CWT), by introducing the daily loadings of each source factor from NMF method. These model results were highly consistent with categorized chemical characteristics of PM2.5, suggesting that NMF linking with hybrid receptor models provides valuable implications for exploring source types and source areas of PM2.5. Meanwhile, biomass combustion and coal combustion comparably contributed to the high PM2.5 concentrations indicating control strategy in South China in spring.

Characteristics and risk assessments of heavy metals in fine and coarse particles in an industrial area of central China.

In order to investigate the pollution level and chemical form transformation characteristics of heavy metals, atmospheric fine particles and coarse particles were collected in an urban industrial area of Zhuzhou City in central China during winter and summer. The results indicated that PM2.5 and PM10 all showed similar time variation, with the highest concentration in winter (112.1 µg/m3, 210.3 µg/m3) and the lowest concentration in summer (44.4 µg/m3, 81.0 µg/m3), respectively. As for heavy metals carried by atmospheric particles, only Cu had similar time variation with particle concentration and was mainly in oxidisable fraction. Zn, Pb and Cd were chiefly distributed in acid-extractable fraction, and Zhuzhou City was extremely polluted by these three heavy metals which mainly came from Qingshui Pond Industrial Area. Moreover, risk assessment results indicated that this area had high ecological risks on the environment and potential non-carcinogenic health effects and low carcinogenic risk to human health, especially for children. In addition, leaching test of atmospheric particles showed that the releasing of heavy metals in simulated acid rain primarily came from acid-extractable fraction, especially in winter, and the chemical form transformation followed a pattern of from stable state to unstable state after dissolving by acid rain.

Channel-length-dependent performance of photosensitive organic field-effect transistors.

Pentacene is a small molecule organic semiconductor and has high absorption in the UV and visible region. In this work, we report the channel-length-dependent performance of bottom-gate top-contact photosensitive organic field-effect transistors based on pentacene with different channel lengths ranging from 25 to 150 µm. The results show that, for a given drain voltage, the photoresponsivity, external quantum efficiency, and specific detectivity decrease with increasing channel length. For a given channel length and gate voltage, the photoresponsivity, external quantum efficiency, and specific detectivity increase with drain voltages, and then tend to saturate at high drain voltages.

Development of a relative potency test using ELISA for human rabies vaccines.

The NIH potency test for human rabies vaccines has disadvantages for use, especially in developing countries where rabies is endemic and prophylaxis needs ample, rapid, and reliable vaccine supplies. In China, 60-75 million doses of human rabies vaccines are administered each year. Vaccine quality control is of paramount importance, as is the release of potency-validated vaccines. We intended to design an alternative to the NIH in vivo method, and developed a relative potency test using an ELISA. Using Pearson's correlation analysis, we found a close relationship between the rabies vaccine glycoprotein content in vitro and the potency values in vivo. We suggest the relative potency test developed here as a simplified method for human rabies vaccine quality control in China and a possible alternative to the NIH method.