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Size-Dependent Photothermal Conversion and Photoluminescence of Theranostic NaNdF4 Nanoparticles under Excitation of Different-Wavelength Lasers
摘要： The narrow absorption and emission bands, long fluorescence lifetime, and excellent stability of rare earth nanoparticles (referred to as RE NPs) make them very attractive for multimodal imaging and therapy of cancer. Their narrow absorption requires the careful selection of laser wavelength to achieve the best performance, particularly for RE NPs simultaneously having photothermal and photoluminescent properties (e.g. Nd-based nanoparticles), which has not been investigated. Herein we prepared a series of different sized NaNdF4 nanoparticles (referred to as NNF NPs) (i.e. 4.7, 5.9, 12.8, and 15.6 nm) from ultra-small nanoclusters and investigated their in vitro and in vivo size-dependent photothermal conversion and photoluminescence under irradiation by a 793 nm laser and an 808 nm laser, respectively. We find that all nanoparticles exhibited the better photothermal conversion performance under the irradiation of the 808 nm laser than under the 793 nm laser, of which 12.8 nm NNF NPs showed the best performance, and the temperature of their solution can be quickly increased from 30 ℃ to around 60 ℃ within 10 min under the irradiation of the 808 nm laser with a power intensity of 0.75 W/cm2. When we used the 793 nm laser to excite these NNF NPs, we find that all nanoparticles exhibited the stronger photoluminescence in the second near-infrared window (NIR-Ⅱ) than under the excitation by the 808 nm laser, of which 15.6 nm NNF NPs possessed the strongest NIR-II luminescence. We then modified 12.8 nm NNF NPs with phospholipid carboxyl PEG and functionalize with RGD for actively targeted imaging of cancer. The NaNdF4@PEG@RGD nanoparticles (referred to as NNF-P-R NPs) have good biocompatibility, stability and excellent targeting capability. The in vivo result show that 12.8 nm NNF NPs exhibited better photothermal conversion performance under the irradiation of the 808 nm laser, and stronger NIR-Ⅱ fluorescence under irradiation of the 793 nm laser, which is consistent with in vitro result. This work demonstrates the significance of selection of proper laser wavelength for maximally taking advantage of RE nanoparticles for the diagnosis and treatment of cancer.
关键词： NaNdF4 nanoparticles,photothermal conversion,size-dependence,NIR-II fluorescence imaging,photoluminescence
更新于2025-09-11 14:15:04
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Slipped Structure of Covalent Organic Framework Facilitates Two‐Photon Adsorption for Improving Near‐Infrared Excited Fluorescence Imaging
摘要： Fluorescent materials exhibiting the characteristics of strong two-photon absorption (TPA) are extensively used for nonlinear optics, bio-imaging and phototherapy. One practical approach to obtain fluorescent materials with high TPA performance is to polymerize molecular chromophores to form π-conjugated structure. This leads to the increase in TPA cross-section per chromophore, however, efforts to towards this direction was capped by the lack of long-range ordering in the structure and the strong π-π stacking between the chromophores. Here, we reported the rational design of benzothiadiazole-based covalent organic framework (COF) for promoting TPA performance and obtaining the efficient two-photon excited fluorescence. Structure characterizations and spectroscopic studies revealed that the enhancement in TPA performance was attributed to the donor-π-acceptor-π-donor (D-π-A-π-D) configuration of the chromophore, long-range order, and large π-conjugation domain of COF crystals. The structural slipping in TPA-COF not only attenuates the π-π stacking interaction between the layers, but more importantly, overcomes the aggregation-caused emission quenching of the chromophores for improving near-infrared two-photon excited fluorescence imaging.
关键词： covalent organic framework,long-range order,two-photon absorption,slipped structure,fluorescence imaging
更新于2025-09-11 14:15:04
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Slipped Structure of Covalent Organic Framework Facilitates Two-Photon Adsorption for Improving Near-Infrared Excited Fluorescence Imaging
摘要： Fluorescent materials exhibiting the characteristics of strong two-photon absorption (TPA) are extensively used for nonlinear optics, bio-imaging and phototherapy. One practical approach to obtain fluorescent materials with high TPA performance is to polymerize molecular chromophores to form π-conjugated structure. This leads to the increase in TPA cross-section per chromophore, however, efforts to towards this direction was capped by the lack of long-range ordering in the structure and the strong π-π stacking between the chromophores. Here, we reported the rational design of benzothiadiazole-based covalent organic framework (COF) for promoting TPA performance and obtaining the efficient two-photon excited fluorescence. Structure characterizations and spectroscopic studies revealed that the enhancement in TPA performance was attributed to the donor-π-acceptor-π-donor (D-π-A-π-D) configuration of the chromophore, long-range order, and large π-conjugation domain of COF crystals. The structural slipping in TPA-COF not only attenuates the π-π stacking interaction between the layers, but more importantly, overcomes the aggregation-caused emission quenching of the chromophores for improving near-infrared two-photon excited fluorescence imaging.
关键词： covalent organic framework,long-range order,two-photon absorption,slipped structure,fluorescence imaging
更新于2025-09-11 14:15:04
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Clinical application of indocyanine green-fluorescence imaging during hepatectomy
摘要： In hepatobiliary surgery, the fluorescence and bile excretion of indocyanine green (ICG) can be used for real-time visualization of biological structure. Fluorescence cholangiography is used to obtain fluorescence images of the bile ducts following intrabiliary injection of 0.025?0.5 mg/mL ICG or intravenous injection of 2.5 mg ICG. Recently, the latter technique has been used in laparoscopic/robotic cholecystectomy. Intraoperative fluorescence imaging can be used to identify subcapsular hepatic tumors. Primary and secondary hepatic malignancy can be identified by intraoperative fluorescence imaging using preoperative intravenous injection of ICG through biliary excretion disorders that exist in cancerous tissues of hepatocellular carcinoma (HCC) and in non-cancerous hepatic parenchyma around adenocarcinoma foci. Intraoperative fluorescence imaging may help detect tumors to be removed, especially during laparoscopic hepatectomy, in which visual inspection and palpation are limited, compared with open surgery. Fluorescence imaging can also be used to identify hepatic segments. Boundaries of hepatic segments can be visualized following injection of 0.25?2.5 mg/mL ICG into the portal veins or by intravenous injection of 2.5 mg ICG following closure of the proximal portal pedicle toward hepatic regions to be removed. These techniques enable identification of hepatic segments before hepatectomy and during parenchymal transection for anatomic resection. Advances in imaging systems will increase the use of fluorescence imaging as an intraoperative navigation tool that can enhance the safety and accuracy of open and laparoscopic/robotic hepatobiliary surgery.
关键词： liver resection,colorectal liver metastasis (CRLM),Indocyanine green (ICG),hepatocellular carcinoma (HCC),fluorescence imaging,intraoperative cholangiography
更新于2025-09-11 14:12:44
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[American Society of Agricultural and Biological Engineers 2017 Spokane, Washington July 16 - July 19, 2017 - ()] 2017 Spokane, Washington July 16 - July 19, 2017 - <i>Phenotyping of Arabidopsis for drought stress response using kinetic chlorophyll fluorescence imaging</i>
摘要： Drought stress is one of the major concerns in global agricultural production. Developing an efficient phenotyping technology can bridge the knowledge gap between the plant phenotype and genotype, which can promote the progress of breeding for drought tolerant accessions and provide economic benefits for the producers and consumers. This research was aimed to investigate the plant phenotyping for drought stress responses of two different genotypes of Arabidopsis using chlorophyll fluorescence imaging. 59 treatment groups (three plants for each group) of each genotype were withholding being watered for 8 days as the drought stress treatment, and the other 59 groups considered as control were regularly watered with 6 ml 1% nutrient solution every day. The kinetic chlorophyll fluorescence images of the drought treatment groups and the control groups were acquired at day 1, 3, 5, 7 and 8 after the drought stress treatment started. The conventional chlorophyll fluorescence parameters and the leaf area index were then extracted from the images. In addition, associated morphological and physiological parameters were also assayed. To construct combinatorial images, the sequential forward selection (SFS) algorithm was used to select the maximum contrast images between two genotypes and the linear discriminant analysis (LDA) was used to build combinatorial images. Finally, combinatorial images were analyzed, indicating combinatorial images are valuable in drought stress studies. Above all, the study showed that AQ and osca1 presented different drought stress responses during the treatment period based on the conventional chlorophyll parameters and combinatorial images.
关键词： drought stress,Arabidopsis,plant phenotyping,combinatorial imaging,Chlorophyll fluorescence imaging
更新于2025-09-10 09:29:36
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Indocyanine Green labeling for optical and photoacoustic imaging of Mesenchymal Stem Cells after in vivo transplantation
摘要： The transplantation of Mesenchymal Stem Cells (MSCs) holds great promise for the treatment of a plethora of human diseases, but new non-invasive procedures are needed to monitor the cell fate in vivo. Already largely used in medical diagnostics, the fluorescent dye Indocyanine Green (ICG) is an established dye to track limited numbers of cells by optical imaging, but it can be visualized also by Photoacoustic Imaging (PAI), which provides a higher spatial resolution than pure near infrared fluorescence imaging (NIRF). Because of its successful use in clinical and preclinical examinations, we chose ICG as PAI cell labeling agent. Optimal incubation conditions were defined for an efficient and clinically translatable MSC labeling protocol, such that no cytotoxicity or alterations of the phenotypic profile were observed, and a consistent intracellular uptake of the molecule was achieved. Suspensions of ICG-labeled cells were both optically and optoacoustically detected in vitro, revealing a certain variability in the photoacoustic spectra acquired by varying the excitation wavelength from 680 to 970 nm. Intramuscular engraftments of ICG-labeled MSCs were clearly visualized by both PAI and NIRF over few days after transplantation in the hindlimb of healthy mice, suggesting that the proposed technique retains a considerable potential in the field of transplantation-focused research and therapy.
关键词： Indocyanine Green,Near Infrared Fluorescence Imaging,Photoacoustic Imaging,Cell tracking,Stem Cells
更新于2025-09-10 09:29:36
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Camouflaged Nanosilver with Excitation Wavelength Dependent High Quantum Yield for Targeted Theranostic
摘要： The present study shows the thorough investigations on optical properties and hydrodynamic diameters of glutathione (GSH) stabilized nanosilver clusters (AgNC) at different stages of synthesis and engineering for the optimized absolute quantum yield to generate fluorescent images of Dalton Lymphoma Ascites (DLA) tumour bearing mice. The initial increment of quantum yield was wavelength dependent and finally it became 0.509 which was due to the camouflaging or entrapment of AgNC in macrophages membranes. The potentiality of macrophages membrane camouflaged silver nanoclusters (AgM) was reflected in the cell viability assay and confocal based live dead cell assay where the AgM has better cell killing effect compared to AgNC with reduced dosage and in vivo mice imaging generated the clear visualization at the tumour sites. Therefore, from the present study, it can be considered that the camouflaged nanosilver can be used for targeted theranostic applications.
关键词： nanosilver clusters,macrophage membrane,theranostic,fluorescence imaging,quantum yield
更新于2025-09-10 09:29:36
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Quantitative fluorescence imaging determines the absolute number of locked nucleic acid oligonucleotides needed for suppression of target gene expression
摘要： Locked nucleic acid based antisense oligonucleotides (LNA-ASOs) can reach their intracellular RNA targets without delivery modules. Functional cellular uptake involves vesicular accumulation followed by translocation to the cytosol and nucleus. However, it is yet unknown how many LNA-ASO molecules need to be delivered to achieve target knock down. Here we show by quantitative fluorescence imaging combined with LNA-ASO microinjection into the cytosol or unassisted uptake that ～105 molecules produce >50% knock down of their targets, indicating that a substantial amount of LNA-ASO escapes from endosomes. Microinjected LNA-ASOs redistributed within minutes from the cytosol to the nucleus and remained bound to nuclear components. Together with the fact that RNA levels for a given target are several orders of magnitude lower than the amounts of LNA-ASO, our data indicate that only a minor fraction is available for RNase H1 mediated reduction of target RNA. When non-specific binding sites were blocked by co-administration of non-related LNA-ASOs, the amount of target LNA-ASO required was reduced by an order of magnitude. Therefore, dynamic processes within the nucleus appear to influence the distribution and activity of LNA-ASOs and may represent important parameters for improving their efficacy and potency.
关键词： RNase H1,Locked nucleic acid,nuclear accumulation,microinjection,gene knock down,antisense oligonucleotides,quantitative fluorescence imaging
更新于2025-09-10 09:29:36
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Fluorescence imaging of <i>Escherichia coli</i> on a rotating optical disk
摘要： We constructed a ?uorescence image from a rotating optical disk sample by aligning laser-scanned results based on positioning marks formed on the disk substrate. When Escherichia coli cells and 0.75-μm-diameter polystyrene beads were placed on the sample surface and a cell staining solution was used, ?uorescence from only E. coli cells was observed in the obtained image. This indicates that E. coli cells can be distinguished from polystyrene beads, an abiotic substance, in one image. A promising utilization of this method is as a sensor for ?nding targets among contaminants on a large area.
关键词： fluorescence imaging,Escherichia coli,sensor,polystyrene beads,optical disk
更新于2025-09-10 09:29:36
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Doxorubicin-loaded protease-activated near-infrared fluorescent polymeric nanoparticles for imaging and therapy of cancer
摘要： Despite significant progress in the field of oncology, cancer remains one of the leading causes of death. Chemotherapy is one of the most common treatment options for cancer patients but is well known to result in off-target toxicity. Theranostic nanomedicines that integrate diagnostic and therapeutic functions within an all-in-one platform can increase tumor selectivity for more effective chemotherapy and aid in diagnosis and monitoring of therapeutic responses. Material and methods: In this work, theranostic nanoparticles were synthesized with commonly used biocompatible and biodegradable polymers and used as cancer contrast and therapeutic agents for optical imaging and treatment of breast cancer. These core–shell nanoparticles were prepared by nanoprecipitation of blends of the biodegradable and biocompatible amphiphilic copolymers poly(lactic-co-glycolic acid)-b-poly-l-lysine and poly(lactic acid)-b-poly(ethylene glycol). Poly-l-lysine in the first copolymer was covalently decorated with near-infrared fluorescent Alexa Fluor 750 molecules. Results: The spherical nanoparticles had an average size of 60–80 nm. The chemotherapeutic drug doxorubicin was encapsulated in the core of nanoparticles at a loading of 3% (w:w) and controllably released over a period of 30 days. A 33-fold increase in near-infrared fluorescence, mediated by protease-mediated cleavage of the Alexa Fluor 750-labeled poly-l-lysine on the surface of the nanoparticles, was observed upon interaction with the model protease trypsin. The cytocompatibility of drug-free nanoparticles and growth inhibition of drug-loaded nanoparticles on MDA-MB-231 breast cancer cells were investigated with a luminescence cell-viability assay. Drug-free nanoparticles were found to cause minimal toxicity, even at high concentrations (0.2–2,000 μg/mL), while doxorubicin-loaded nanoparticles significantly reduced cell viability at drug concentrations .10 μM. Finally, the interaction of the nanoparticles with breast cancer cells was studied utilizing fluorescence microscopy, demonstrating the potential of the nanoparticles to act as near-infrared fluorescence optical imaging agents and drug-delivery carriers. Conclusion: Doxorubicin-loaded, enzymatically activatable nanoparticles of less than 100 nm were prepared successfully by nanoprecipitation of copolymer blends. These nanoparticles were found to be suitable as controlled drug delivery systems and contrast agents for imaging of cancer cells.
关键词： enzymatic activation,nanoprecipitation,theranostics,PEG,poly-l-lysine,PLGA,block copolymers,nanomedicine,fluorescence imaging,drug delivery,nanoparticles,PLA
更新于2025-09-10 09:29:36