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Preliminary Study of MR and Fluorescence Dual-mode Imaging: Combined Macrophage-Targeted and Superparamagnetic Polymeric Micelles
摘要： Purpose: To establish small-sized superparamagnetic polymeric micelles for magnetic resonance and fluorescent dual-modal imaging (MRI) and investigated the macrophage-targeted in vitro. Methods: A new class of superparamagnetic iron oxide nanoparticles (SPIONs) and Nile red-co-loaded mPEG-Lys3-CA4-NR/SPION polymeric micelles was synthesized to label Raw264.7 cells. The physical characteristics of the polymeric micelles were assessed, the T2 relaxation rate was calculated, and the effect of labeling on the cell viability and cytotoxicity was also determined in vitro. In addition, further evaluation of the application potential of the micelles was conducted via in vitro MRI. Results: The diameter of the mPEG-Lys3-CA4-NR/SPION polymeric micelles was 33.8 ± 5.8 nm on average. Compared with the hydrophilic SPIO, mPEG-Lys3-CA4-NR/SPION micelles increased transversely (r2), leading to a notably high r2 from 1.908 μg/mL-1S-1 up to 5.032 μg/mL-1S-1, making the mPEG-Lys3-CA4-NR/SPION micelles a highly sensitive MRI T2 contrast agent, as further demonstrated by in vitro MRI. The results of Confocal Laser Scanning Microscopy (CLSM) and Prussian blue staining of Raw264.7 after incubation with micelle-containing medium indicated that the cellular uptake efficiency is high. Conclusion: We successfully synthesized dual-modal MR and fluorescence imaging mPEG-Lys3-CA4-NR/SPION polymeric micelles with an ultra-small size and high MRI sensitivity, which were effectively and quickly uptaken into Raw 264.7 cells. mPEG-Lys3-CA4-NR/SPION polymeric micelles might become a new MR lymphography contrast agent, with high effectiveness and high MRI sensitivity.
关键词： macrophage-targeted,polymeric micelles,MRI,SPIONs,fluorescence imaging
更新于2025-09-23 15:21:01
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Digital scanned laser lighta??sheet fluorescence lifetime microscopy with widea??field timea??gated imaging
摘要： We develop a multidimensional fluorescence imaging technique by implementing a wide-field time-gated fluorescence lifetime imaging into digital scanned laser light-sheet microscopy (FLIM-DSLM) to measure 3D fluorescence lifetime distribution in mesoscopic specimens with high resolution. This is achieved by acquiring a series of time-gated images at different relative time delays with respect of excitation pulses at different depths. The lifetime is determined for each voxel by iteratively fitting to single exponential decay. The performance of the developed system is evaluated with the measurements of a lifetime reference Rhodamine 6G solution and a sub-resolution fluorescent bead phantom. We also demonstrate the application performances of this system to ex vivo and in vivo imaging of Tg(kdrl:EGFP) transgenic zebrafish embryos, illustrating the lifetime differences between the GFP signal and the autofluorescence signal. The results show that FLIM-DSLM can be used for sample size up to a few millimeters and can be utilized as a powerful and robust method for biomedical research, for example as a readout of protein-protein interactions via F?rster resonance energy transfer.
关键词： Fluorescence lifetime imaging,light-sheet fluorescence microscopy,time-resolved fluorescence imaging
更新于2025-09-23 15:19:57
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Synthesis of folic acid conjugated photoluminescent carbon quantum dots with ultrahigh quantum yield for targeted cancer cell fluorescence imaging
摘要： Folic acid functionalized carbon quantum dot (FA-CQD) with ultrahigh quantum yield (50%) were synthesized by one-pot hydrothermal route using citric acid. The synthesized CQDs were characterized by fluorescence spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and X-ray diffraction. The cell viability of about 95% and 97% were obtained for MTT assay of the CQDs and FA-CQDs toward MCF-7 cells after 24 h of incubation respectively. The FA-CQDs were successfully applied for targeted imaging of cervical cancer (type HeLa) and human breast adenocarcinoma (type MCF7) cells using fluorescence microscope.
关键词： HeLa cancer cell,Ultra high quantum yield CQDs,MCF-7 cancer cell,Fluorescence imaging,Targeted cancer imaging
更新于2025-09-23 15:19:57
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IGCS Intraoperative Technology Taskforce. Update on near infrared imaging technology: beyond white light and the naked eye, indocyanine green and near infrared technology in the treatment of gynecologic cancers
摘要： Surgery, by its very nature, relies on the ability of the surgeon to visualize and distinguish healthy and non-healthy tissue or structures. Without advanced technology, surgeons can visualize only that which can be seen with the naked eye or using white light imaging. Critical information on tissues, anatomical structures and physiological processes remain hidden and difficult to discern. Fluorescence imaging augments the basic surgical information. This form of imaging entails injecting a contrast or fluorescence agent (fluorophore) that is then illuminated by the appropriate wavelength of light required to excite the fluorophore. The excited fluorophore emits light of a slightly longer wavelength that is selectively imaged to produce a fluorescence image. The first fluorescent agent used in surgery was an intravenous injection of fluorescein, where it was used to enhance intracranial neoplasms. One particular imaging agent, indocyanine green, has been a significant driver of adoption of fluorescence imaging. Indocyanine green was first developed in 1955 by Kodak Research Laboratories and was approved by the Food and Drug Administration (FDA) in 1959 for retinal angiography. Since that time, this fluorophore has been used for a variety of surgical applications due to its unique properties: relative non-toxicity, depth of visualization through tissue, and remaining confined to intravascular and lymphatic spaces due to binding predominately to lipoproteins. The large depth of visualization results from the fluorescence properties of bound indocyanine green which is optimally excited with 805 nm light and emits over an approximate wavelength range from 810 nm to 875 nm. These near infrared wavelengths, invisible to the naked eye, pass through tissue particularly well due to the low adsorption of light by the various structures of tissue, such as hemoglobin and water. As a result, the tissue is relatively transparent to this light and images of structures as much as 5 mm below the tissue surface can be formed. By comparison, fluorescence imaging with fluorescein images only 2–3 mm below the tissue surface; thus subsurface structures cannot be imaged using visible fluorophores.
关键词： gynecologic cancers,fluorescence imaging,indocyanine green,near infrared imaging,surgical technology
更新于2025-09-23 15:19:57
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Gel-based analysis of protein phosphorylation status by rapid fluorometric staining using TAMRA-labeled Phos-tag
摘要： Phosphorylation, one of the most common post-translational modifications of proteins, plays a critical role in many biological processes. We have previously developed several analytical methods for determining the phosphorylation status of certain proteins by using a phosphate-capturing binuclear metal complex known as Phos-tag. Here, we describe a novel method for the gel-based in vitro analysis of the phosphorylation status of a protein by a simple and rapid fluorometric staining method that uses a tetramethylrhodamine (TAMRA)-labeled Phos-tag derivative (TAMRA–Phos-tag). The entire staining protocol, which requires less than 2 h to complete, uses three buffer solutions for staining, washing, and dilution, respectively, at room temperature. The gel-based analysis of phosphoproteins in a polyacrylamide gel can be conducted by using a fluorescence imaging scanner with a 532-nm excitation laser and a 580-nm longpass emission filter. As a practical example of the use of the TAMRA–Phos-tag staining method, we examined the time course of dephosphorylation of ovalbumin by an alkaline phosphatase. In addition, inhibitor profiling of a tyrosine kinase Abl was performed by using an Abl-substrate (GST-Abltide) and an Abl-inhibitor (Imatinib).
关键词： phosphoprotein-selective staining,kinase assay,fluorescence imaging,phosphatase assay,gel-based analysis
更新于2025-09-23 15:19:57
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Rapid, non-invasive fluorescence margin assessment: Optical specimen mapping in oral squamous cell carcinoma
摘要： Objective: Surgical resection remains the primary treatment for the majority of solid tumors. Despite efforts to obtain wide margins, close or positive surgical margins (< 5 mm) are found in 15–30% of head and neck cancer patients. Obtaining negative margins requires immediate, intraoperative feedback of margin status. To this end, we propose optical specimen mapping of resected tumor specimens immediately after removal. Materials and methods: A first-in-human pilot study was performed in patients (n = 8) after infusion of fluorescently labeled antibody, panitumumab-IRDye800 to allow surgical mapping of the tumor specimen. Patients underwent standard of care surgical resection for head and neck squamous cell carcinoma (HNSCC). Optical specimen mapping was performed on the primary tumor specimen and correlated with pathological findings after tissue processing. Results: Optical mapping of the specimen had a 95% sensitivity and 89% specificity to detect cancer within 5 mm (n = 160) of the cut surface. To detect tumor within 2 mm of the specimen surface, the sensitivity of optical specimen mapping was 100%. The maximal observed penetration depth of panitumumab-IRDye800 through human tissue in our study was 6.3 mm. Conclusion: Optical specimen mapping is a highly sensitive and specific method for evaluation of margins within < 5 mm of the tumor mass in HNSCC specimens. This technology has potentially broad applications for ensuring adequate tumor resection and negative margins in head and neck cancers.
关键词： Near-infrared,Oral cancer,Fluorescence imaging,Squamous cell carcinoma,Molecular imaging,Optical specimen mapping
更新于2025-09-19 17:15:36
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Fluorescence contrast-enhanced proliferative lesion imaging by enema administration of indocyanine green in a rat model of colon carcinogenesis
摘要： The fluorescent contrast agent indocyanine green (ICG) is approved by the Food and Drug Administration for clinical applications. We previously reported that cultured human colon tumor cells preferentially take up ICG by endocytic activity in association with disruption of their tight junctions. The present study explored ICG availability in fluorescence imaging of the colon to identify proliferative lesions during colonoscopy. The cellular uptake of ICG in cultured rat colon tumor cells was examined using live-cell imaging. Colon lesions in rats administered an ICG-containing enema were further assessed in rats with azoxymethane-induced colon carcinogenesis, using in vivo endoscopy, ex vivo microscopy, and immunofluorescence microscopy. The uptake of ICG by the cultured cells was temperature-dependent. The intracellular retention of the dye in the membrane trafficking system suggested endocytosis as the uptake mechanism. ICG administered via enema accumulated in colon proliferative lesions ranging from tiny aberrant crypt foci to adenomas and localized in proliferating cells. Fluorescence endoscopy detected these ICG-positive colonic proliferative lesions in vivo. The immunoreactivity of the tight-junction molecule occludin was altered in the proliferative lesions, suggesting the disruption of the integrity of tight junctions. These results suggest that fluorescence contrast-enhanced imaging following the administration of an ICG-containing enema can enhance the detection of mucosal proliferative lesions of the colon during colonoscopy. The tissue preference of ICG in the rat model evaluated in this study can be attributed to the disruption of tight junctions, which in turn promotes endocytosis by proliferative cells and the cellular uptake of ICG.
关键词： colon tumor,endoscopy,fluorescence imaging,indocyanine green,tight junction
更新于2025-09-19 17:15:36
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Identification of extrahepatic metastasis of hepatocellular carcinoma using indocyanine green fluorescence imaging
摘要： Background/purpose: Intraoperative fluorescence imaging with indocyanine green (ICG) plays a significant role in the identification of hepatocellular carcinoma (HCC) during Hepatectomy. Despite that, few researchers have reported using ICG fluorescence imaging to detect extrahepatic metastases. Herein, we report the successful application of ICG fluorescence imaging in the detection of extrahepatic metastatic lesions from primary liver cancer. Methods : In two HCC patients, a near-infrared fluorescence imaging system was used to intraoperatively examine the abdominal cavity implantation metastasis after multiple hepatectomy and the primary tumor after the pre-operation with ICG . Results: In the first case, the abdominal cavity implantation metastasis exhibited intense fluorescence and clear boundaries of tumors during abdominal tumor resection, and there was no fluorescence in the resection margin. In the second case, a new lesion that was not detected by preoperative imaging examination was found in the omentum by ICG fluorescence imaging. Intraoperative rapid freezing pathology showed that it was an adenocarcinoma. Accordingly, we revised the tumor staging. Conclusion: ICG fluorescence imaging can not only detect intrahepatic metastases, but also extrahepatic metastases. Furthermore, it can help surgeons correct tumor staging during surgery.
关键词： indocyanine green,implantation metastasis,fluorescence imaging
更新于2025-09-19 17:15:36
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Highly biocompatible graphene quantum dots: green synthesis, toxicity comparison and fluorescence imaging
摘要： Graphene quantum dots (GQDs) have tremendous potential in biological imaging due to their bright visible photoluminescence mission. However, the tedious preparation procedures and potential toxicity of GQDs greatly limit their application in biological field. Here, highly biocompatible GQDs (HGQDs) have been successfully prepared only by glucose in aqueous solution. Compared with GQDs prepared from conventional methods (CGQDs), the cytotoxicity of HGQDs reduced by more than 60%, and the flow cytometric analysis of the normal cells treated with HGQDs showed that the early and late apoptotic rate reduced by more than 72% and 40%, respectively. In vitro fluorescence imaging showed that both cells and bacteria could be imaged by HGQDs, and the morphology of cells and bacteria could be kept to a maximum extent. A long-term in vivo study revealed that no obvious organ (heart, liver, spleen, lung and kidney) damage or lesions were observed, and the blood–brain barrier (BBB) could be overcome, which provides the possibility for treatment and diagnosis of brain-related diseases. With adequate studies of biocompatibility, both in vitro and in vivo, HGQDs may be considered for further biological application.
关键词： biocompatibility,biological application,fluorescence imaging,Graphene quantum dots
更新于2025-09-19 17:13:59
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Semiconducting Polymer Nanoparticles as Theranostic System for Near-Infrared II Fluorescence Imaging and Photothermal Therapy under Safe Laser Fluence
摘要： Theranostic systems combining fluorescence imaging in the second near infrared window (NIR-II, 1000-1700 nm) and photothermal therapy (PTT) under safe laser fluence have great potential in preclinical research and clinical practice, but the development of such systems with sufficient effective NIR-II brightness and excellent photothermal properties is still challenging. Here we report a theranostic system based on semiconducting polymer nanoparticles (L1057 NPs) for NIR-II fluorescence imaging and PTT under a 980 nm laser irradiation, with low (25 mW/cm2) and high (720 mW/cm2) laser fluence, respectively. Taking into consideration multiple parameters including extinction coefficient, quantum yield and portion of emission in the NIR-II region, L1057 NPs have much higher effective NIR-II brightness than most reported organic NIR-II fluorophores. The high brightness, together with good stability and excellent biocompatibility, allows for real-time visualization of whole-body and brain vessels and detection of cerebral ischemic stroke and tumors with high clarity. The excellent photothermal properties and high maximal permissible exposure (MPE) limit at 980 nm allow L1057 NPs for PTT of tumors under safe laser fluence. This study demonstrates that L1057 NPs behave as an excellent theranostic system for NIR-II imaging and PTT under safe laser fluence and have great potential for a wide range of biomedical applications.
关键词： nanoparticle,effective NIR-II brightness,semiconducting polymer,photothermal therapy,fluorescence imaging
更新于2025-09-19 17:13:59