- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fuel Waste to Fluorescent Carbon Dots and Its Multifarious Applications
摘要： Herein, we report the fluorescent carbon dots (KCDs) from kerosene fuel soot via simple one pot oxidative acid treatment. The obtained KCDs were thoroughly characterized by pivotal techniques. The prepared KCDs are 5 nm sized quasi-spherical particles and exhibited an outstanding stability against pH, NaCl and light irradiation. Intriguingly, the KCDs display an excitation wavelength independent emissive property. Further, the KCDs were successfully utilized for multifarious applications such as photoinduced electron transfer (PET) and sensing studies. For PET studies, charged porphyrins (tetra pyridyl and tetra sulphonato) were selected and the fluorescence of associated porphyrin was quenched and the quenching is due electron transfer. The lower recombination rate obtained from transient absorption spectral studies suggests that KCDs can be used as electron shuttling material in a cascade system of photovoltaic device. On the other hand, the fluorescent nature of KCDs was used for the selective and sensitive detection of explosives and metal ions. The detection limit for picric acid, Cu2+ and Fe3+ is found to be 86 ng/ml, 15.3 ng/ml and 0.36 μg/ml respectively. Moreover, the unreacted soot during the acid treatment has been calcined and used as an affordable filter bed for waste water treatment.
关键词： Explosives,PET,Kerosene Soot,Carbon dots,Metal ion detection
更新于2025-09-23 15:21:21
-
A measurement of the attenuation of radiation from F-18 by a PET/MR scanner
摘要： The attenuation of 511 keV photons by the structure of a PET/MR scanner was measured prior to energizing the magnet. The exposure rate from a source of fluorine‐18 was measured in air and, with the source placed at the isocenter of the instrument, at various points outside of the scanner. In an arc from 45 to 135 degrees relative to the long axis of the scanner and at a distance of 1.5 m from the isocenter, the attenuation by the scanner is at least 5.6 half‐value layers from the MR component alone and at least 6.6 half‐value layers with the PET insert installed. This information could inform better design of the radiation shielding for PET/MR scanners.
关键词： PET/MR,self-attenuation
更新于2025-09-23 15:21:21
-
<i>In Vitro</i> Ligand Binding Kinetics Explains the Pharmacokinetics of [ <sup>18</sup> F]FE-PE2I in Dopamine Transporter PET Imaging
摘要： Two of the most popular positron emission tomography (PET) tracers, [11C]PE2I and [18F]FE-PE2I, used to quantify dopamine transporters (DAT), display dissimilar kinetic behavior in in vivo assays. This difference can be explained by comparing values of kinetic rate constants, which characterize interaction of these tracers with DAT sites in vitro. At the same time, this kinetic analysis showed that the overall binding mechanism is similar for these two tracers and includes a fast step of complex formation followed by a slow isomerization step of this complex. Comparison with previous PE2I data revealed that isomerization of the DAT complex with PE2I occurs three times faster than in the case of FE-PE2I, which leads to the slower onset of peak specific binding of the former tracer in the DAT-rich regions. Therefore, ligands with slower isomerization on-rate, including [18F]FE-PE2I, seem to be better tracers in vivo, and their properties can be predicted in vitro.
关键词： isomerization,ligand binding kinetics,FE-PE2I,Dopamine transporter,DAT,PET,PE2I
更新于2025-09-23 15:21:21
-
Preclinical Evaluation of a Novel <sup>18</sup> F-Labeled dTCO-Amide Derivative for Bioorthogonal Pretargeted Positron Emission Tomography Imaging
摘要： Pretargeted positron emission tomography (PET) imaging based on the bioorthogonal inverse-electron-demand Diels?Alder reaction between tetrazines (Tz) and trans-cyclooctenes (TCO) has emerged as a promising tool for solid tumor imaging, allowing the use of short-lived radionuclides in immune-PET applications. With this strategy, it became possible to achieve desirable target-to-background ratios and at the same time to decrease the radiation burden to nontargeted tissues because of the fast clearance of small PET probes. Here, we show the synthesis of novel 18F-labeled dTCO-amide probes for pretargeted immuno-PET imaging. The PET probes were evaluated regarding their stability, reactivity toward tetrazine, and pharmacokinetic pro?le. [18F]MICA-213 showed an extremely fast kinetic rate (10,553 M?1 s?1 in 50:50 MeOH/water), good stability in saline and plasma up to 4 h at 37 °C with no isomerization observed, and the biodistribution in healthy mice revealed a mixed hepatobiliary and renal clearance with no de?uorination and low background in other tissues. [18F]MICA-213 was further used for in vivo pretargeted immune-PET imaging carried out in nude mice bearing LS174T colorectal tumors that were previously treated with a tetrazine-modi?ed anti-TAG-72 monoclonal antibody (CC49). Pretargeted μPET imaging results showed clear visualization of the tumor tissue with a signi?cantly higher uptake when compared to the control.
关键词： immuno-PET,tetrazines,bioorthogonal chemistry,Pretargeted PET imaging,trans-cyclooctenes
更新于2025-09-23 15:21:01
-
Characterization of monolithic GAGG:Ce coupled to both PMT and SiPM array for gamma imaging in Nuclear Medicine
摘要： GaGG:Ce scintillation crystal is very useful for nuclear imaging purposes, thanks to its several advantages (high density, short decay time, high light yield and good energy resolution, no self-activity, no hygroscopic). However, only the recent improvements in the growth processes make it available with large size, in order to use it in monolithic configuration. The main drawbacks of pixelated crystals, as non-uniform response, high production costs and optical light loss, could be therefore overcome. In this work the characterization of this promising crystal coupled both to a single channel PMT (spectrometric purpose) and to a new technology SiPM (50% PDE and 74% geometrical fill factor) has been performed. The detection efficiency results good both for SPECT (87% at 122 keV) and for PET (18% at 356 keV) applications. However, the unexpected result arises from the energy resolution: at 356 keV 8.9% and 8.0% for single channel PMT and SiPM configuration, respectively. In other terms, the used SiPM allows to achieve higher energy resolution than single channel PMT. Moreover, a high imaging performance has been observed, with a millimeter intrinsic spatial resolution.
关键词： SPECT,PET PET/CT,Gamma camera,Intra-operative probes,Scintillators and scintillating fibres and light guides,coronary CT angiography (CTA),Scintigraphy and whole-body imaging
更新于2025-09-23 15:21:01
-
<sup>86/90</sup> Y-Labeled Monoclonal Antibody Targeting Tissue Factor for Pancreatic Cancer Theranostics
摘要： Pancreatic cancer is highly aggressive, with a median survival time of less than 6 months and a 5-year overall survival rate of around 7%. The poor prognosis of PaCa is largely due to its advanced stage at diagnosis and the lack of efficient therapeutic options. Thus, the development of an efficient, multifunctional PaCa theranostic system is urgently needed. Overexpression of tissue factor (TF) has been associated with increased tumor growth, angiogenesis, and metastasis in many malignancies, including pancreatic cancer. Herein, we propose the use of a TF-targeted monoclonal antibody (ALT836) conjugated with the pair 86/90Y as a theranostic agent against pancreatic cancer. For methods, serial PET imaging with 86Y-DTPA-ALT836 was conducted to map the biodistribution the tracer in BXPC-3 tumor-bearing mice. 90Y-DTPA-ALT836 was employed as a therapeutic agent that also allowed tumor burden monitoring through Cherenkov luminescence imaging. The results were that the uptake of 86Y-DTPA-ALT836 in BXPC-3 xenograft tumors was high and increased over time up to 48 h postinjection (p.i.), corroborated through ex vivo biodistribution studies and further confirmed by Cherenkov luminescence Imaging. In therapeutic studies, 90Y-DTPA-ALT836 was found to slow tumor growth relative to the control groups and had significantly smaller (p < 0.05) tumor volumes 1 day p.i. Histological analysis of ex vivo tissues revealed significant damage to the treated tumors. The conclusion is that the use of the 86/90Y theranostic pair allows PET imaging with excellent tumor-to-background contrast and treatment of TF-expressing pancreatic tumors with promising therapeutic outcomes.
关键词： pancreatic cancer,yttrium-86,radioimmunotherapy,tissue factor,yttrium-90,theranostics,positron emission tomography (PET)
更新于2025-09-23 15:21:01
-
Synthesis and analysis of 64Cu-labeled GE11-modified polymeric micellar nanoparticles for EGFR-targeted molecular imaging in a colorectal cancer model
摘要： Polymeric micellar nanoparticles represent versatile and biocompatible platforms for targeted drug delivery. However, tracking their biodistribution, stability, and clearance profile in vivo is challenging. The goal of this study was to prepare surface-modified micelles with peptide GE11 for targeting the epidermal growth factor receptor (EGFR). In vitro fluorescence studies demonstrated significantly higher internalization of GE11-micelles into EGFR-expressing HCT116 colon cancer cells versus EGFR-negative SW620 cells. Azo coupling chemistry of tyrosine residues in the peptide backbone with aryl diazonium salts was used to label the micelles with radionuclide 64Cu for positron emission tomography (PET) imaging. In vivo analysis of 64Cu-labeled micelles showed prolonged blood circulation and predominant hepatobiliary clearance. The biodistribution profile of EGFR-targeting GE11-micelles was compared with non-targeting HW12-micelles in HCT116 tumor-bearing mice. PET revealed increasing tumor-to-muscle ratios for both micelles over 48 h. Accumulation of GE11-containing micelles in HCT116 tumors was higher compared to HW12-decorated micelles. Our data suggest that the efficacy of image-guided therapies with micellar nanoparticles could be enhanced by active targeting, as demonstrated with cancer biomarker EGFR.
关键词： polymeric micelles,epidermal growth factor receptor (EGFR),64Cu,GE11 peptide,Colorectal cancer,positron emission tomography (PET)
更新于2025-09-23 15:21:01
-
Exploiting Wavelength Orthogonality for Successive Photoinduced Polymerization-Induced Self-Assembly and Photo-Crosslinking
摘要： We report a facile benchtop process for the synthesis of cross-linked polymeric nanoparticles by exploiting wavelength-selective photochemistry to perform orthogonal photoinduced polymerization-induced self-assembly (Photo-PISA) and photo-crosslinking processes. We first established that the water-soluble photocatalyst, zinc meso-tetra(N-methyl-4-pyridyl) porphine tetrachloride (ZnTMPyP) could activate the aqueous PET-RAFT dispersion polymerization of hydroxypropyl methacrylate (HPMA). This photo-PISA process could be conducted under low energy red light (λ max = 595 nm, 10.2 mW/cm2) and without deoxygenation due to the action of the singlet oxygen quencher, biotin (vitamin B7), which allowed for the synthesis of a range of nanoparticle morphologies (spheres, worms, and vesicles) directly in 96-well plates. To perform wavelength selective nanoparticle cross-linking, we added the photoresponsive monomer, 7-[4-(trifluoromethyl)coumarin] methacrylamide (TCMAm) as a comonomer without inhibiting the evolution of the nanoparticle morphology. Importantly, under red light, exclusive activation of the photo-PISA process occurs, with no evidence of TCMAm dimerization under these conditions. Subsequent switching to a UV source (λ max = 365 nm, 10.2 mW/cm2) resulted in rapid cross-linking of the polymer chains, allowing for retention of the nanoparticle morphology in organic solvents. This facile synthesis of cross-linked spheres, worms, and vesicles demonstrates the utility of orthogonal light-mediated chemistry for performing decoupled wavelength selective chemical processes.
关键词： photoinduced polymerization-induced self-assembly,wavelength orthogonality,polymeric nanoparticles,photo-crosslinking,PET-RAFT polymerization
更新于2025-09-23 15:21:01
-
[O-methyl-11C]N-(4-(4-(3-Chloro-2-methoxyphenyl)-piperazin-1-yl)butyl)-1H-indole-2-carboxamide ([11C]BAK4-51) Is an Efflux Transporter Substrate and Ineffective for PET Imaging of Brain D3 Receptors in Rodents and Monkey
摘要： Selective high-affinity antagonists for the dopamine D3 receptor (D3R) are sought for treating substance use disorders. Positron emission tomography (PET) with an effective D3R radioligand could be a useful tool for the development of such therapeutics by elucidating pharmacological specificity and target engagement in vivo. Currently, a D3R-selective radioligand does not exist. The D3R ligand, N-(4-(4-(3-chloro-2-methoxyphenyl)piperazin-1-yl)butyl)-1H-indole-2-carboxamide (BAK4-51, 1), has attractive properties for PET radioligand development, including full antagonist activity, very high D3R affinity, D3R selectivity, and moderate lipophilicity. We labeled 1 with the positron-emitter carbon-11 (t1/2 = 20.4 min) in the methoxy group for evaluation as a radioligand in animals with PET. However, [11C]1 was found to be an avid substrate for brain efflux transporters and lacked D3R-specific signal in rodent and monkey brain in vivo.
关键词： dopamine D3 receptors,radiolabeling,PET,efflux transporter substrate,antagonist
更新于2025-09-23 15:21:01
-
Ag2Au50(PET)36 Nanocluster: Dimeric Assembly of Au25(PET)18 Enabled by Silver Atoms
摘要： Assembly of atomically precise metal nanoclusters is now in the research spotlight, which offers exciting opportunities to gain fundamental insights into the hierarchical assembly of nanoparticles. However, it is still extremely challenging for controllable assembly of individual nanoclusters at a molecular- or atomic-level. Herein we report the dimeric assembly of Au25(PET)18 (PET = 2-phenylethanethiol), where two Au25(PET)18 monomers are bridged together by two Ag atoms to form the Ag2Au50(PET)36 dimer. The Ag2Au50(PET)36 dimer is an exclusive mesomer, which has not been found in any other chiral metal nanoclusters belonging to the racemic category. Furthermore, the Ag2Au50(PET)36 dimer is distinct from the Au25(PET)18 monomer on the optical, electronic, and catalytic properties. This study is expected to provide a feasible strategy to precisely modulate the assembly of metal nanoclusters with controllable structures and properties.
关键词： dimer,assembly,properties,Ag2Au50(PET)36,nanocluster
更新于2025-09-23 15:21:01