查找使用阿拉丁产品的科研文献

Low-LOD organic thin-film NO2 gas sensor based on a porous polystyrene structure

Xi Lu,Baijin Wang,Ziyang Cui,Kaicaiayi Kelimu,Lu Wang,Lijuan Wang

Enhancing gas diffusion and interfacial accessibility in organic semiconductor films is essential for achieving high-performance nitrogen dioxide (NO 2 ) sensing at low concentration levels. This study presents a strategy for enhancing the nitrogen dioxide (NO 2 ) sensing performance of α-hexathiophene (α-6T) and Copper (II) Phthalocyanine (CuPc) organic semiconductor films by introducing a porous polystyrene (PS) structure onto SiO 2 substrates by solution spin-coating. The influence of PS concentration on the morphology and gas-sensing response characteristics was investigated. At an optimal PS concentration of 7 mg/mL, the sensitivity of the sensors was enhanced, and the theoretical limit of detection (LOD) was reduced. The PS/CuPc sensor achieved a sensitivity of 270.96%/ppm and a theoretical LOD as low as 299 ppb. We attribute this performance enhancement to the PS structure increasing the specific surface area of the organic semiconductor film, thereby promoting the diffusion and desorption of gas molecules within the semiconductor film. This work provides a reliable preparation method and mechanistic insights for developing gas sensors with low detection limits.

Pd@Ir-LOD multienzyme utilizing endogenous lactate consumption cooperates with photothermal for tumor therapy

Ye Zichen,Li Yun,Li Jingchao,Hu Xinyan,Zheng Jinyang,Zhang Gongxin,Xiang Sijin,Zhu Tianbao,Guo Zhide,Chen Xiaolan

Lactic acid (LA) plays a major role in the occurrence, development, and spread of cancer. Enlightened by its high accumulation in tumor site, a novel lactate oxidase (LOD) conjugated two-dimensional Pd@Ir nanoplatform (Pd@Ir-LOD, PIL) was fabricated to combine cascade reaction with photothermal for tumor therapy. In detail, the overexpressed LA in tumor microenvironment (TME) was a key factor to activate the PIL-based cascade reaction: (1) Plenty of H 2 O 2 could be generated from LA by the catalysis of LOD with O 2 ; (2) potent OH was produced from H 2 O 2 due to the peroxidase (POD)-like activity of PIL; (3) meantime, PIL’s catalase (CAT)-like activity could decompose part H 2 O 2 into O 2 to achieve the purpose of LA cyclic oxidization. Moreover, the reduced glutathione (GSH) scavenging capability of PIL might protect the produced reactive oxygen species (ROS) from being cleared to further improve the cascade therapeutic effect. More importantly, PIL had excellent photothermal conversion efficiency (37.35%) and manifested a surprising temperature rising effect in tumor. Taken together, the decreasing LA concentration, accumulation of high-toxic ROS, the depletion of GSH together with the higher intra-tumoral temperature potently enhanced in vivo antitumor therapy. Therefore, a promising therapeutic tactic based on PIL integrating endogenous LA consumption, chemodynamic therapy (CDT), and photothermal therapy (PTT) has been put forward.

Low LOD and Non-Adsorption Probing of Functionalized Magnetic Beads Using Quartz Crystal Microbalance Under Bimodal Magnetic Field

Dongyu Chen,Yumei Wen,Ping Li,Yao Wang

Dual-Emission RhB@UIO-67-0.2: A Platform for Ultra-Low LOD Ammonia Detection and On-Site Visual Recognition

ShuHuan Chen,Panweiyi Wang,Teshale Ayano Begeno,Afaq Nazir,ZhenXia Du,Shuping Qu

Luminescent metal-organic frameworks (LMOFs) have emerged as promising materials for optical sensing, owing to their tunable luminescent properties. However, most existing LMOF-based sensors rely on single-wavelength fluorescence intensity changes, which suffer from poor resistance to environmental fluctuations due to the absence of auxiliary reference signals, limiting their accuracy, especially for trace ammonia(NH 3 ) below the human olfactory threshold, which evades sensory perception yet poses long-term risks. To address this limitation, UIO-67-x where x denotes the molar ratio of terephthalic acid (H 2 BDC) to biphenyl-4,4`-dicarboxylic acid (H 2 BPDC) was designed. By optimizing the ligand ratio, UIO-67-0.2 was synthesized with well-defined crystallinity, large specific surface area and high fluorescence emission peak intensity. Its regular structure enables efficient encapsulation of rhodamine B (RhB) forming the dual-emission [email protected] platform. This platform has two adjustable emission peaks, both of which respond sensitively and synchronously to ammonia, thereby strengthening signal reliability and anti-interference capability through dual-channel synergistic verification. Notably [email protected] achieves an ultra-low NH 3 limit of detection (LOD) of 0.2 ppm, far below the olfactory threshold, and maintains remarkable stability after 5 cycles with stable reusability. Combining experiments and Density functional theory (DFT) calculations the quenching mechanism is clarified as the synergistic effect of static quenching and charge transfer. A [email protected] drop-cast film exhibits naked-eye distinguishable color change at 2.5 ppm NH 3 under 365 nm Ultraviolet(UV) light. It remains unchanged with other volatile organic compounds (VOCs) and shows concentration-dependent color gradation for semi-quantitative assessment. Furthermore, Digital conversion of fluorescence color signals via ΔE analysis enabled truly quantitative ammonia detection with a linear calibration curve ( R 2 = 0.968), eliminating the subjectivity of naked-eye judgment. This work develops a dual-mode LMOF for sub-olfactory-threshold NH 3 detection and informs anti-interference dual-emission platform design enabling on-site low-cost monitoring.

A novel gold particle-based paper sensor for sensitively detecting carprofen in bovine muscle

Guanqiong Na,Xiaofei Hu,Yaning Sun,Guangxu Xing,Yunrui Xing,Gaiping Zhang

Carprofen (CAR) is a non-steroidal anti-inflammatory drug commonly used to treat various musculoskeletal diseases and infections in food animals. While CAR residues in food animal tissues caused by veterinary medicine abuse are a potential danger to human health. In this study, a high-affinity monoclonal antibody (mAb) against CAR was prepared, and then an immunochromatographic strip for rapidly screening CAR in bovine muscle was developed to help enforce regulatory compliance. The visual detection limit (cut-off value) by the naked eye of the fabricated test strip was 12.5 ng g−1. Scanning by the strip reader, the IC50 of the test strip was calculated as 1.743 ng g−1, and the limit of detection (LOD, IC10) was 0.283 ng g−1. The proposed method provided an efficient tool for monitoring CAR in bovine muscle. Meantime, our work suggested great potential for the analysis of CAR residues in other food matrixes.

Simultaneous determination and quantitation of hypolipidemic drugs in fingerprints by UPLC-Q-TRAP/MS

Qiuyao Du,Yunfeng Zhang,Jifen Wang,Bingjie Liu

An ultra-performance liquid chromatography tandem triple quadrupole compound linear ion trap mass spectrometry (UPLC-Q-TRAP/MS) method was developed and validated for the detection of hypolipidemic drugs in fingerprints. 13 hypolipidemic drugs were well separated by the gradient elution of 0.01% formic acid in water and methanol at a flow rate of 0.4 mL/min within 11 min. The analytes were detected in positive (ESI + ) and negative (ESI - ) modes and scanned using scheduled multiple reaction monitoring-information dependent acquisition-enhanced product ion (SMRM-IDA-EPI) for best selectivity and sensitivity. The calibration curves showed good linearity in the range of 0.050–50.000 ng/patch with coefficients ( r 2 ) higher than 0.9904 for all analytes. Meantime, the LODs and LLOQs were in ranges of 0.001–0.034 and 0.003–0.050 ng/patch. The accuracies, intra-day and inter-day precision ranged from −13.3 to 0.3%, 1.1–10.4% and 3.7–14.5%, respectively. The recoveries ranged from 79.9 to 114.8%, while the absolute and relative matrix effects were in the range of 83.0–107.2% and 2.2–9.7%. By comparing the non-spiked fingerprints from healthy volunteers with the fingerprints obtained from patients, demonstrated that the method was competent for determination and quantitation of hypolipidemic drugs in fingerprints.

An in-situ plasmonic spectroscopy based biosensor for detection of copper (II) ions highlighting analytical specifications

Zheng Dou,Wenjia Zhang,Qian Du,Guohua Liu

Whether the copper ion (Cu 2+ ) exposed to us functions as a necessary part of metabolism or toxicant for organs depends on subtle concentration difference of trace-level. Although miniature sensors have combined various recognition probes and signal transducer moieties to form novel sensing scheme, haunting limits on practicality or analytical specifications like sensitivity and selectivity remain thwarting high Cu 2+ detection performance with excellent cost-effectiveness. In this work, we report a Cu 2+ -specific biosensor integrating Deoxyribozyme (DNAzyme) and single-particle plasmon. The basic principle here is that severity of cleavage corresponding to various Cu 2+ concentration determines these elements’ aggregation capacity. The evaluation criteria is set up on the shift of dark-field Localized Surface Plasmon Resonance (LSPR) wavelengths caused by the binding with free AuNPs. Not only excellent analytical specifications like limit of detection (LOD) of 0.082 nM, broad dynamic range from 0.1 nM–5 μM, ultra-specificity are demonstrated but recovery rate with real sample and term of validity is also investigated to be 101.25 ± 9.15 % at 3 nM and longer than 9 days corroborating its potential for practical scenario. Therefore, the sensor is introduced as an attract alternative to remove hindrances for high sensing performance and to generalize on-chip cleavage-inducing spectral shift to heavy metal ions concentration measurement.

Integrated label-free erbium-doped fiber laser biosensing system for detection of single cell Staphylococcus aureus

Jiandong Liu,Bin Liu,Juan Liu,Xing-Dao He,Jinhui Yuan,Zabih Ghassemlooy,Hamdi Torun,Yong-Qing Fu,Xuewu Dai,Wai Pang Ng,Richard Binns,Qiang Wu

A critical challenge to realize ultra-high sensitivity with optical fiber interferometers for label free biosensing is to achieve high quality factors (Q-factor) in liquid. In this work a high Q-factor of 10 5 , which significantly improves the detection resolution is described based on a structure of single mode -core-only -single mode fiber (SCS) with its multimode (or Mach-Zehnder) interference effect as a filter that is integrated into an erbium-doped fiber laser (EDFL) system for excitation. In the case study, the section of core-only fiber is functionalized with porcine immunoglobulin G (IgG) antibodies, which could selectively bind to bacterial pathogen of Staphylococcus aureus ( S. aureus ). The developed microfiber-based biosensing platform called SCS-based EDFL biosensors can effectively detect concentrations of S. aureus from 10 to 10 5  CFU/mL, with a responsivity of 0.426 nm wavelength shift in the measured spectrum for  S. aureus  concentration of 10 CFU/mL. The limit of detection (LoD) is estimated as 7.3 CFU/mL based on the measurement of S. aureus with minimum concentration of 10 CFU/mL. In addition, when a lower concentration of 1 CFU/mL is applied to the biosensor, a wavelength shift of 0.12 nm is observed in 10% of samples (1/10), indicating actual LoD of 1 CFU/mL for the proposed biosensor. Attributed to its good sensitivity, stability, reproducibility and specificity, the proposed EDFL based biosensing platform has great potentials for diagnostics.

Direct detection of polystyrene microspheres by using easily fabricated Ag core embedded Au film SERS substrates with high sensitivity

Yansheng Liu,Zhenle Qin,Xiaobo Jia,Jin Zhou,Hongli Li,Xiaohong Wang,Guofu Wang

Plastics as very important materials have been extensively utilized, and they make people’s lives comparative and economic. However, recent studies find that the micro/nano-plastic particles degenerating from plastic materials especially for food containers may lead to some unknown diseases when they enter into the human lung or stomach. The methods of detecting micro/nano-plastic particles are urgently required, and conventional methods necessitate intricate pre-processing steps and specialized equipment. Hence, this paper introduces a highly sensitive and direct detection method based on Surface-Enhanced Raman Spectroscopy (SERS) in quantitatively and qualitatively analyzing polystyrene (PS) nanoplastics that are drop cast on substrate. The mechanism of SERS performance of the proposed Ag core embedded Au film (Ag@AuFilm) SERS substrate is studied by using the finite-different time-domain (FDTD) method. By optimizing the gap distance between the Ag core and the Au film, PS nanoplastics with three diameters were used to validate the effectiveness of the SERS substrate. The limits of detection (LOD) for PS nanoparticles with diameters of 50 nm, 70 nm, and 310 nm in DI water and real-river water were the same and the corresponding LODs were 50, 50, and 25 μg/mL, respectively. Thus, this study proposes an easily fabricated SERS substrate and provides a rapid, quantitative, and qualitative method for detecting PS nanoplastics. This new way of addressing the pervasive issue of nanoplastics pollution provided an accurate, efficient, and rapid detection of the nanoplastics.

A facile label-free colorimetric aptasensor for ricin based on the peroxidase-like activity of gold nanoparticles

Jingting Hu,Pengjuan Ni,Haichao Dai,Yujing Sun,Yilin Wang,Shu Jiang,Zhuang Li

AuNPs possess peroxidase-like activity that could catalyze 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2, leading to color change of the solution. Herein we propose a simple and sensitive colorimetric aptasensor for the quantitative analysis of ricin by using AuNPs. It is shown that the peroxidase-like activity of AuNPs can be improved by surface activation with target-specific aptamers. However, with target molecules, the aptamer is desorbed from the AuNPs' surface, resulting in a decrease of the catalytic abilities of AuNPs. The color change of the solution was relevant to the target concentration, and this can be judged by the naked eye and monitored by UV-vis spectrometry. The linear range for the current analytical system was from 0.05 nM to 10 nM. The corresponding limit of detection (LOD) was 0.05 nM. Some other proteins such as thrombin (Th), glucose oxidase (GOx), and bovine albumin (BSA) all had a negligible effect on the determination of ricin. What is more, several practical samples spiked with ricin were analyzed using the proposed method with excellent recoveries. This colorimetric aptasensor is superior to the other conventional methods owing to its simplicity, low cost, and high sensitivity.

Dramatic fluorescence enhancement of PCN-224 and its application in “turn off” immunoassay for sensitive detection of E. coli O157:H7 in milk

Bolong Fang,Xin Liu,Juan Peng,Yuzhi Li,Zhiyong Gong,Weihua Lai

In this study, a type of luminescent porous coordination network-224 (PCN-224) in alkaline conditions was synthesized with the dramatic fluorescence enhancement by 20.4 times, which was explained by the fact that the decrease of Zr 4+ content in alkaline conditions resulted in the partial recovery of the electron cloud density of 4,4′,4′′,4′′′-(Porphine-5,10,15,20-tetrayl) tetrakis(benzoic acid) (TCPP). Given the large overlap between the excitation spectrum of PCN-224 and the absorption band of Ag nanoparticles (Ag NPs), the coating of the Ag layer on PCN-224 triggered the fluorescence quenching effect, which was applied to “turn off” fluorescence immunoassay for sensitive detection of Escherichia coli O157:H7 ( E. coli O157:H7) in milk. The proposed immunoassay reached a low limit of detection (LOD) of 3.3 × 10 2 CFU mL −1 , 29.7 times more sensitive than the conventional ELISA. It will provide a novel alternative strategy for sensitively detecting pathogenic bacteria in the field of food safety.

Simple, Visual, Point-of-Care SARS-CoV-2 Detection Incorporating Recombinase Polymerase Amplification and Target DNA–Protein Crosslinking Enhanced Chemiluminescence

Hui Chen,Zhiyuan Zhuang,Naihan Xu,Ying Feng,Kaixin Fang,Chunyan Tan,Ying Tan

The ongoing COVID-19 pandemic, driven by persistent SARS-CoV-2 transmission, threatens human health worldwide, underscoring the urgent need for an efficient, low-cost, rapid SARS-CoV-2 detection method. Herein, we developed a point-of-care SARS-CoV-2 detection method incorporating recombinase polymerase amplification (RPA) and DNA–protein crosslinking chemiluminescence (DPCL) (RPADPCL). RPADPCL involves the crosslinking of biotinylated double-stranded RPA DNA products with horseradish peroxidase (HRP)-labeled streptavidin (SA-HRP). Modified products are captured using SA-labeled magnetic beads, and then analyzed using a chemiluminescence detector and smartphone after the addition of a chemiluminescent substrate. Under optimal conditions, the RPADPCL limit of detection (LOD) was observed to be 6 copies (within the linear detection range of 1–300 copies) for a plasmid containing the SARS-CoV-2 N gene and 15 copies (within the linear range of 10–500 copies) for in vitro transcribed (IVT) SARS-CoV-2 RNA. The proposed method is convenient, specific, visually intuitive, easy to use, and does not require external excitation. The effective RPADPCL detection of SARS-CoV-2 in complex matrix systems was verified by testing simulated clinical samples containing 10% human saliva or a virus transfer medium (VTM) spiked with a plasmid containing a SARS-CoV-2 N gene sequence or SARS-CoV-2 IVT RNA. Consequently, this method has great potential for detecting targets in clinical samples.