BIOMATERIALS
·
2019
·
IF 10.273
Yanbing Wang,Zhuo Wang,Caina Xu,Huayu Tian,Xuesi Chen
Despite multifunctional nanoparticles using for photothermal therapy can efficiently kill cancer cells, their further application is still hindered by the intrinsic high uptake in the reticuloendothelial system (RES) organs, causing the slow elimination from the body and potential toxicity to the body. Therefore, it is ideal to develop multifunctional nanoparticles which process the ability to effectively accumulate in tumors, while the nanoparticles can be rapidly excreted from the body via renal clearance after effective treatment. Herein, we report the multifunctional nanoparticles (FeTNPs) based on the coordination interaction of phenolic group and metal iron, which are composed of ferric iron, tannic acid (TA) and poly (glutamic acid)- graft -methoxypoly (ethylene glycol) (PLG- g -mPEG). FeTNPs exhibit the following highlighted features: (1) The effective accumulation in the tumor tissue is achieved based on EPR effect. (2) The dual photoacoustic (PA)/magnetic resonance (MR) imaging capacity can provide guidance for the photothermal therapy (PTT). (3) FeTNPs can be dynamically disassembled by deferoxamine mesylate (DFO) to accelerate elimination of the nanoparticles, thus reducing the potential toxicity for the body. The DFO triggered dynamic disassembling strategy may open a new avenue to overcome the dilemma between EPR effect and renal clearance.
研究领域:
生物医学工程
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癌症治疗
·
纳米医学
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产品关联
DOI
PubMed
高影响因子
POLYMER
·
2024
·
IF 4.1
Qisong Lin,Junting Gao,Shuimi Zhong,Yongjun Wang,Wangyang Lu,Wenxing Chen
One of the major issues concerning poly(ethylene terephthalate) (PET) produced with titanium-based catalysts is its sensitivity to high-temperature oxidation, which results in performance loss and discoloration. Here, the thermo-oxidative phenomena of titanium-catalyst-produced PET during its synthesis and post-processing in the presence of hindered phenol anti-oxidant Irganox 1425 has been investigated by a spin-trapping technique. Three types of spin adducts have been determined and quantified; –O− • CH− is the dominant radical intermediate, while • CH 2 − and –O− • CH− are mainly produced by the decomposition of diethylene glycol (DEG) units. An excessively high DEG content leads to instability of PET chains at high temperatures and so is not conducive to suppressing oxidation. An anti-oxidant can effectively eliminate radicals induced by thermo-oxidative reactions and improve the thermal stability of PET, especially in the post-processing stage. A comprehensive thermal oxidation mechanism is proposed, in which PET thermolysis starts with hydrogen abstraction to produce –O− • CH−, and then auto-oxidation ensues by radical intermediates attacking other PET chains. The cyclic reaction is reasonably terminated by the anti-oxidant serving as a hydrogen donor to quench radical intermediates.
研究领域:
材料科学
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高分子化学
·
物理化学
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产品关联
DOI
高影响因子
MACROMOLECULES
·
2026
·
IF 5.7
Geng Ziran,Du Xingchan,Wang Minxue,Qiu Shi,Li Chi,Tang Jian,Liu Wei,Wang Baolong,Gu Pengfei,Pan Yanxiong,Ji Xiangling
Poly( m -phenylene isophthalamide) (PMIA) is a high-performance meta-aramid polymer whose processing is governed by chain segmental dynamics. Herein, PMIA segmental dynamics were evaluated by combining spin-labeled PMIA and continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy. The rotational correlation time (τ c ) obtained from EPR simulation exhibited a sharp increase near 4.5 wt %, close to the entanglement concentration ( c e ) determined from rheological measurements, demonstrating the reliability of spin-label EPR in determining segmental motion and entanglement. The dissolution behavior of PMIA was monitored by EPR spectroscopy, and the solubilizing salt concentration at which τ c changed abruptly closely matched that at which the solution became transparent. Additionally, τ c increased rapidly at low molecular weights before leveling off at higher molecular weights, reflecting the development and saturation of entanglement. These features establish spin-label CW-EPR as a complementary tool for elucidating polymer solution behavior at the microscopic scale in systems containing additives and for guiding polymer processing optimization.
✓ 已验证
DOI
高影响因子
Magnetic Resonance Letters
·
2022
·Vol. 3
·期 1
·61-66
·
IF 0
Bei Hu,Fushan Geng,Ming Shen,Bingwen Hu
Dual-mode electron paramagnetic resonance (EPR) spectroscopy was employed to analyze redox mechanisms in lithium cobalt oxide LiCoO 2 (LCO) cathode material during delithiation and lithiation. It was found that the O3-II could not fully convert back to the pristine O3–I phase while oxygen vacancies quickly generate and accumulate during the cycling. Our study paves the way for better understanding the doping effects of different elements on LiCoO 2 in the future.
研究领域:
材料科学
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电化学
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储能
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光谱学
✓ 已验证
DOI
MACROMOLECULAR RAPID COMMUNICATIONS
·
2026
·
IF 4.1
Tong Zhao,Tianquan You,Hongchi Tian,Wenquan Chen,Nanying Ning,Bing Yu,Peng-Fei Cao,Ming Tian
Dynamic crosslinked elastomers derived from synthetic rubbers represent a promising strategy to combine the reprocessability of thermoplastics with the mechanical robustness of vulcanized rubbers. However, the development of dynamic networks in saturated polyolefin elastomers like ethylene propylene rubber (EPR) is intrinsically constrained by low reactive density and inefficient dynamic crosslinking kinetics. Herein, we present a topology-engineered dynamic crosslinked EPR elastomer constructed via a trifunctional boronic ester crosslinking strategy which enhances crosslinking efficiency despite the limited reactive density. Hydroxyl-functionalized EPR was first synthesized via a controlled epoxidation–hydrolysis route, followed by dynamic network formation using a tri-functional boronic ester crosslinker. In contrast to conventional dynamic crosslinked systems employing di-functional crosslinkers, such network based on tri-functional crosslinker exhibits significantly improved crosslinking density, improved tensile strength (3.5 MPa), and elongation at break (312%), as well as faster stress relaxation without increased activation energy. The multi-functional junctions effectively suppress the formation of dangling chains with promoted network rearrangement, enabling efficient reprocessing with up to 75% retention of tensile strength. This work highlights the functional numbers of junctions as a critical design parameter to overcome the crosslinking limitations in low-functionality elastomers, offering a generalizable approach to fabricating high-performance, recyclable EPR-based materials.
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DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2020
·
IF 3.905
Qingguo Zhou,Zhongyang Luo,Guoxiang Li,Simin Li
Lignin pyrolysis is a promising method for the sustainable production of phenolic compounds from biomass. However, detailed knowledge about the radicals involved in this process and their influence during the coking is missing. Herein, we report on the pyrolysis of guaiacol, a lignin monomer at 600 °C under inert and hydrogen gas conditions. During the pyrolysis process, the formed radicals were detected by two improved electron paramagnetic resonance spectroscopy methods. Successfully observed o-phenyl semiquinone radical anion, cyclopentadienyl radical, methyl radical, hydroxyl radical, methoxy radical, phenyl radical, phenoxy radical, etc. during the pyrolysis of guaiacol, as well as the changes of related radicals in different pyrolysis stages. It was found that o-semiquinone radical anions and cyclopentadienyl radicals were the key free radicals in the generation of coke and tar during the pyrolysis process. And through hydrogenation pyrolysis experiments, it was verified that the relative content of o-semiquinone radical and the solid coke were reduced with a hydrogen supply source. Our results showed that by controlling the key free radicals in the coking process, the formation of coke can be suppressed and the conversion efficiency can be improved.
研究领域:
化学工程
·
生物质能研究
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产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2016
·
IF 4.509
Ruili Zhang,Marcos de Oliveira,Zaiyang Wang,Roger Gomes Fernandes,Andrea S. S. de Camargo,Jinjun Ren,Long Zhang,Hellmut Eckert
The structure of glasses in the systems (100 – x)B2O3–xPbF2 (x = 30, 40, and 50) and 50B2O3–(50 – x)PbO–xPbF2 (x = 5, 10, 15, 20, 25, 30, 35, 40, and 45) has been studied by solid state NMR and EPR spectroscopies. On the basis of 11B and 19F high resolution solid state NMR as well as on 11B/19F double resonance results, we develop a quantitative structural description on the atomic scale. 19F NMR results indicate a systematic dependence of the fluoride speciation on PbF2 content: At low x-values, F– ions are predominantly found on BO3/2F– units, whereas, at higher x-values, fluoride tends to be sequestrated into amorphous domains rich in PbF2. In addition, both pulsed EPR studies of Yb3+ doped glasses and photophysical studies of Eu3+ doped samples indicate a mixed fluoride/borate coordination of the rare-earth ions and the absence of nanophase segregation effects.
研究领域:
材料科学
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玻璃化学
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光谱学
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固体物理
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无机化学
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOBIOTECHNOLOGY
·
2025
·
IF 12.6
Liu Yiqiong,Xu Dailin,Cheng Jianwei,Fei Zhengyue,Dong Haiqing,Li Yan,Li Yongyong,Lu Peihua
Targeted drug delivery remains pivotal for enhancing therapeutic efficacy in cancer treatment. While nanomedicines harness the enhanced permeability and retention (EPR) effect for passive tumor accumulation, their efficacy is often hindered by physiological barriers that limit optimal delivery. Active delivery strategies by immune cell (neutrophils etc.) hitchhiking offer a promising approach to surmount these obstacles; however, attenuated tumor-associated inflammation restricts their tumor-directed migration. Here, we present a biomimetic nanoplatform based on polydopamine nanoparticles coated with bacterial outer membrane vesicles (OMV@PDA). Upon single injection, these nanoparticles not only passively accumulate in tumors via the EPR effect and generate localized hyperthermia under near-infrared irradiation to ablate tumor cells and trigger inflammation, but also leverage their pathogen-mimicking coating to promote efficient uptake by circulating neutrophils (83.2% phagocytosis rate). The photothermally amplified inflammation broadcasts “find-me” signals to recruit nanoparticle-laden neutrophils to tumor sites. Consequently, a single injection orchestrates EPR effect and neutrophil hitchhiking for spatiotemporal accumulation, achieving high-intensity and sustained tumor accumulation. Notably, this strategy yielded an remarkable tumor inhibition rate of 95%, underscoring superior therapeutic efficacy. Our findings establish a self-reinforcing paradigm for advancing targeted drug delivery in oncology. Graphical
研究领域:
肿瘤学
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纳米医学
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免疫学
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药物递送
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转化医学
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炎症生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Small Methods
·
2025
·
IF 9.1
Wanli Wang,Yujie Xu,Yuqi Li,Yi Sun,Alistair J. Fielding,Pawin Iamprasertkun,Junwei Yang,Bin Wang,Qiang Li,Mingbo Wu,Han Hu
Hard carbon (HC), a prime anode candidate for sodium-ion batteries, exhibits unresolved charge-state-microstructure debates reveal critical sodium storage mechanism gaps. This study employs electron paramagnetic resonance (EPR) spectroscopy as a principal characterization tool, capitalizing on its unique capability to probe electronic configurations and detect subtle structural transformations in carbon matrices. Through systematic EPR investigations of sodium storage dynamics in varied carbon architectures, the quasi-metallic state of sodium ions stored in closed pores exhibits distinct signal characteristics due to size effect-induced structural confinement, compared to surface storage mechanisms. Furthermore, the underappreciated influence of conductive carbon additives, a ubiquitous component in electrode formulations is specifically addressed, on spectroscopic interpretations. This findings reveal that sodium's distinctive storage states (ionic vs quasi-metallic) and their spatial distribution within carbon matrices induce quantifiable modifications in EPR spectral parameters, including characteristic linewidth broadening and lineshape evolution. The comparative analysis demonstrates that trace amounts (≤10 wt.%) of conductive additives can substantially distort ex situ EPR measurements, with interference patterns exhibiting strong material-dependent behavior. Therefore, the application of conductive additives demands rigorous consideration in EPR-based investigations of energy-storing carbon materials, given their methodological implications.
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产品关联
DOI
PubMed
高影响因子
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
·
2023
·Vol. 120
·期 30
·e2305706120
·
IF 11.1
Jing-Hang Wu,Fei Chen,Tian-Hao Yang,Han-Qing Yu
Singlet oxygen (1O2) plays a pivotal role in numerous catalytic oxidation processes utilized in water purification and chemical synthesis. The spin-trapping method based on electron paramagnetic resonance (EPR) analysis is commonly employed for 1O2 detection. However, it is often limited to time-independent acquisition. Recent studies have raised questions about the reliability of the 1O2 trapper, 2,2,6,6-tetramethylpiperidine (TEMP), in various systems. In this study, we introduce a comprehensive, kinetic examination to monitor the spin-trapping process in EPR analysis. The EPR intensity of the trapping product was used as a quantitative measurement to evaluate the concentration of 1O2 in aqueous systems. This in situ kinetic study was successfully applied to a classical photocatalytic system with exceptional accuracy. Furthermore, we demonstrated the feasibility of our approach in more intricate 1O2-driven catalytic oxidation processes for water decontamination and elucidated the molecular mechanism of direct TEMP oxidation. This method can avoid the false-positive results associated with the conventional 2D 1O2 detection techniques, and provide insights into the reaction mechanisms in 1O2-dominated catalytic oxidation processes. This work underscores the necessity of kinetic studies for spin-trapping EPR analysis, presenting an avenue for a comprehensive exploration of the mechanisms governing catalytic oxidation processes.
研究领域:
分析化学
·
环境科学
·
催化
·
物理化学
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产品关联
DOI
PubMed
高影响因子
Nutrients
·
2026
·Vol. 18
·期 8
·1181
·
IF 5.8
Li Quan,Cheng Li,Peipei Shen,Enchao Zhou,Gui Yin,Xuewen Guo
Background/Objectives:Chlorogenic acid (CGA) is a natural antioxidant widely distributed in various plant foods, exhibiting great potential for the development of natural antioxidant agents and biomedical applications.Methods:In this study, the antioxidant activity of CGA was first characterized via electron paramagnetic resonance (EPR) spectroscopy by determining its scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Meanwhile, its hydroxyl radical (•OH) scavenging activity in aqueous solution was quantitatively evaluated based on the signal intensity changes of DMPO-OH• adducts. Furthermore, a fluorescein-labeled chlorogenic acid derivative (FL-CGA) was utilized to visualize the distribution of CGA in major mouse organs following tail vein injection, with a specific focus on the kidney, and to investigate its penetration capacity into podocytes.Results:The results demonstrated that 0.35 mM CGA exerted potent scavenging activity toward highly reactive and cytotoxic •OH radicals, achieving a scavenging rate of 95.2% in a system where •OH was generated by continuous UV irradiation of 5 mM H2O2aqueous solution for 30 min. Additionally, FL-CGA was specifically accumulated in the kidney and localized to the lysosomes of podocytes, while no signal was detected in the endoplasmic reticulum or mitochondria.Conclusions:This study provides experimental evidence to further elucidate the mechanisms underlying CGA-mediated intervention in renal injury, and lays a foundation for the further development and clinical application of CGA as a natural dietary antioxidant.
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DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2019
·
IF 2.687
Fenhong Liu,Bernard A. Goodman,Xiaojun Tan,Xiangyu Wang,Danxin Chen,Wen Deng
Rubies (Cr: Al 2 O 3 single crystals) with 0.025–0.4 mol% Cr 2 O 3 were prepared by the optical floating zone method, and characterized by X-ray diffraction (XRD), electron paramagnetic resonance (EPR) spectroscopy, optical transmission and photoluminescence (PL). Crystals were free of inclusions and cracks, and had high transmittance in the visible region. In addition to the well-known signals from Cr 3+ in the α-Al 2 O 3 structure, the EPR spectra indicated the presence of very weak signals, which may correspond to paramagnetic centres associated with an oxygen vacancy , and an electron-loss oxygen centre, O − . The concentration of these paramagnetic centres was at a minimum for Cr 2 O 3 concentration of 0.15 mol%, and additional Cr 3+ -derived peaks were also observed with Cr 2 O 3 concentrations >0.15 mol%. The PL spectra also varied with Cr 2 O 3 concentrations; the emission intensities of the PL spectra increased with Cr 2 O 3 concentration for concentrations ≤0.15 mol%, then decreased with the further increases in Cr 2 O 3 . Thus the maximum luminescence emission intensity and the minimum concentration of paramagnetic structural defects were observed with 0.15 mol % Cr 2 O 3 , and the presence of additional interactions involving Cr 3+ ions may contribute to the partial quenching of the luminescence at higher Cr 3+ concentrations. Overall, the optical floating zone method represents an effective and economic approach to the preparation of high quality rubies, and their optimum optical properties were observed with Cr 2 O 3 concentrations of 0.15 mol%.
研究领域:
材料科学
·
光学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）