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Hydrophilic Quantum Dots Functionalized with Gd(III)-DO3A Monoamide Chelates as Bright and Effective T1-weighted Bimodal Nanoprobes
摘要： Magnetic resonance imaging (MRI) is a powerful non-invasive diagnostic tool that enables distinguishing healthy from pathological tissues, with high anatomical detail. Nevertheless, MRI is quite limited in the investigation of molecular/cellular biochemical events, which can be reached by fluorescence-based techniques. Thus, we developed bimodal nanosystems consisting in hydrophilic quantum dots (QDs) directly conjugated to Gd(III)-DO3A monoamide chelates, a Gd(III)-DOTA derivative, allowing for the combination of the advantages of both MRI and fluorescence-based tools. These nanoparticulate systems can also improve MRI contrast, by increasing the local concentration of paramagnetic chelates. transmetallation assays, optical characterization, and relaxometric analyses, showed that the developed bimodal nanoprobes have great chemical stability, bright fluorescence, and high relaxivities. Moreover, fluorescence correlation spectroscopy (FCS) analysis allowed us to distinguish nanosystems containing different amounts of chelates/QD. Also, inductively coupled plasma optical emission spectrometry (ICP – OES) indicated a conjugation yield higher than 75%. Our nanosystems showed effective longitudinal relaxivities per QD and per paramagnetic ion, at least 5 times [per Gd(III)] and 100 times (per QD) higher than the r1 for Gd(III)-DOTA chelates, suitable for T1-weighted imaging. Additionally, the bimodal nanoparticles presented negligible cytotoxicity, and efficiently labeled HeLa cells as shown by fluorescence. Thus, the developed nanosystems show potential as strategic probes for fluorescence analyses and MRI, being useful for investigating a variety of biological processes.
关键词： Quantum Dots,Gd(III)-DO3A monoamide chelates,Fluorescence,MRI,Bimodal nanoprobes
更新于2025-11-21 11:08:12
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Magnetic SERS Composite Nanoparticles for Microfluidic Oil Reservoir Tracer Detection and Nanoprobe Applications
摘要： Composite magnetic nanoparticles are designed and synthesized with different morphologies as surface-enhanced Raman scattering (SERS) substrates or SERS-active particles. Through the incorporation of a magnetic functionality we provide a means to concentrate SERS-active nanoparticles in a low-volume microfluidic channel where the detected entity is now either a flowing analyte (e.g. tracer or chemical) or SERS-active particles contained in a target reservoir fluid. This collection strategy allows for detection using small amounts of material and can be optimized to provide selectivity for trace-level materials detection at the wellsite. We also demonstrate low-concentration detection of dye molecules used for reservoir tracer materials by optimizing the fluid flow rate and the intensity of the magnetic field. Thus, we developed an efficient magnetic SERS microfluidic detection platform for in situ monitoring trace level of analyte molecules. The integration of SERS with microfluidic systems also can extends the application of Raman detection in bio-medical research and microreactor monitoring where low volumes of expensive samples make traditional detection methods ineffective or cost prohibitive.
关键词： surface-enhanced Raman scattering,SERS nanoprobes,magnetic SERS,SERS substrate,nanoparticle,microfluidics
更新于2025-09-23 15:23:52
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Non-Invasive Optical Guided Tumor Metastasis/Vessel Imaging by Using Lanthanide Nanoprobe with Enhanced Down-Shifting Emission beyond 1500 nm
摘要： Visualization of tumor vessels/metastasis and cerebrovascular architecture is vital important for analyzing pathological states of brain diseases and tumor's abnormal blood vessel to improve cancer diagnosis. In vivo fluorescence imaging using second near infrared emission beyond 1500 nm (NIR-IIb) is emerged as a next generation optical imaging method with significant improvement in imaging sensitivity and spatial resolution. Unfortunately, highly biocompatible probe capable of generating NIR-IIb emission with sufficient brightness and uniformed size is still scarce. Here, we have proposed the polyacrylic acid (PAA)-modified NaLnF4:40Gd/20Yb/2Er nanorods (Ln=Y, Yb, Lu, PAA-Ln-NRs) with enhanced downshifting NIR-IIb emission, high quantum yield (QY), relative narrow bandwidth (~160 nm) and high bio-compatibility via Ce3+ doping for high performance NIR-IIb bioimaging. The downshifting emission beyond 1500 nm is improved by 1.75~2.2 times with simultaneously suppressing the upconversion (UC) path in Y, Yb, and Lu hosts via Ce3+ doping. Moreover, compared with the traditionally used Y-based host, the QY of NIR-IIb emission in Lu-based probe in water is improved from 2.2% to 3.6%. The explored bright NIR-IIb emitted PAA-Lu-NRs were used for high sensitivity small tumor (~ 4 mm)/metastatic tiny tumor detection (~ 3 mm), tumor vessel visualization with high spatial resolution (41 μm) and brain vessel imaging. Therefore, our findings open up the opportunity of utilizing lanthanide based NIR-IIb probe with bright 1525 nm emission for in vivo optical-guided tumor vessel/metastasis and non-invasive brain vascular imaging.
关键词： enhancement of downshifting emission,tiny metastatic tumor detection,tumor vascular imaging,rare-earth nanoprobes,brain vascular imaging
更新于2025-09-23 15:23:52
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Plasmonically Coupled Nanoreactors for NIR-Light-Mediated Remote Stimulation of Catalysis in Living Cells
摘要： Artificial nanoreactors that can facilitate catalysis in living systems on-demand with the aid of remotely operable and biocompatible energy-source, are needed to leverage the chemical diversity and expediency of advanced chemical synthesis in biology and medicine. Here, we designed and synthesized plasmonically-integrated nanoreactors (PINERs) with highly tunable structure and NIR-light-induced synergistic function for efficiently promoting unnatural catalytic reactions inside living cells. We devised synthetic approach towards PINERs by investigating the crucial role of metal-tannin coordination polymer nanofilm — the pH-induced decomplexation-mediated phase-transition process — for growing arrays of Au-nanospheroid-units, constructing a plasmonic corona around the proximal and reactant-accessible silica-compartmentalized catalytic nanospace. Owing to the extensive plasmonic coupling effect, PINERs show strong and tunable optical absorption in visible to NIR range, ultrabright plasmonic light scattering, controllable thermoplasmonic effect and remarkable catalysis; and, upon internalization by living cells, PINERs are highly biocompatible and demonstrate dark-field microscopy-based bioimaging features. Empowered with the synergy between plasmonic and catalytic effects and reactant/product transport, facilitated by the NIR-irradiation, PINERs can perform intracellular catalytic reactions with dramatically accelerated rates and efficiently synthesize chemically activated fluorescence-probes inside living cells.
关键词： plasmonic nanoprobes,catalytic nanoreactors,coordination polymer,biorthogonal chemistry,bioimaging
更新于2025-09-23 15:21:01
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Controlled Synthesis of Ag <sub/>2</sub> Te@Ag <sub/>2</sub> S Corea??Shell Quantum Dots with Enhanced and Tunable Fluorescence in the Second Neara??Infrared Window
摘要： Fluorescence in the second near-infrared window (NIR-II, 900–1700 nm) has drawn great interest for bioimaging, owing to its high tissue penetration depth and high spatiotemporal resolution. NIR-II fluorophores with high photoluminescence quantum yield (PLQY) and stability along with high biocompatibility are urgently pursued. In this work, a Ag-rich Ag2Te quantum dots (QDs) surface with sulfur source is successfully engineered to prepare a larger bandgap of Ag2S shell to passivate the Ag2Te core via a facile colloidal route, which greatly enhances the PLQY of Ag2Te QDs and significantly improves the stability of Ag2Te QDs. This strategy works well with different sized core Ag2Te QDs so that the NIR-II PL can be tuned in a wide range. In vivo imaging using the as-prepared Ag2Te@Ag2S QDs presents much higher spatial resolution images of organs and vascular structures as compared with the same dose of Ag2Te nanoprobes administrated, suggesting the success of the core–shell synthetic strategy and the potential biomedical applications of core–shell NIR-II nanoprobes.
关键词： NIR-II nanoprobes,Ag2Te@Ag2S,bioimaging,core–shell quantum dots
更新于2025-09-23 15:19:57
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Luminescent switch of polysaccharide-peptide-quantum dot nanostructures for targeted-intracellular imaging of glioblastoma cells
摘要： Glioblastoma multiforme (or GBM) remains one of the deadliest types of brain cancers. Nanomedicine can offer new strategies for fighting against GBM by combining the earliest possible diagnosis with multiple options of therapy. Hence, in this work, cysteine (Cys) and Poly-L-Arginine (PA) moieties were grafted to carboxymethyl cellulose (CMC) to produce biofunctional hybridized macromolecules (CMC_Cys and CMC_PA). These polymer-peptide conjugates were used simultaneously as surface capping ligands and biofunctional modifiers for the synthesis of ternary Ag-In-S (AIS) quantum dots (AIS QDs) via a green chemical process in aqueous medium and room temperature. These core-shell supramolecular nanostructures (AIS@CMC, AIS@CMC_Cys, and AIS@CMC_PA) were tested as fluorescent nanoprobes (“OFF-ON”) for targeted bioimaging and in vitro intracellular tracking of glioblastoma cells (GBM, U-87 MG). The nanosystems were characterized for physicochemical, structural, and morphological properties by NMR, UV–Vis, PL, FTIR, TEM/EDX/SAED, zeta potential, and DLS. Cytocompatibility was evaluated by mitochondrial activity assay, and confocal laser scanning microscopy was performed for investigating the kinetics of cellular uptake. The grafting caused a noticeable reduction of surface charges, associated with a drastic photoluminescence quenching (i.e., “OFF-state”) of AIS@CMC_Cys and AIS@CMC_PA compared to unmodified AIS@CMC. This effect was smartly applied for bioimaging GBM cells and for monitoring the internalization process by intracellular tracking, which underwent strong “de-quenching” at very early incubation times (~5 min). Thus, these novel hybrid nanocolloids produced via eco-friendly scalable aqueous process show potential as responsive fluorescent bioprobes for bioimaging and tracking intracellular pathways and mechanisms as a powerful weapon for fighting against brain cancer cells.
关键词： nanoconjugates,nanomaterials,colloids,polymer-semiconductor nanoprobes,supramolecular nanoparticles,fluorescent nanoparticles
更新于2025-09-23 15:19:57
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Self-assembling nanoprobes that display two-dimensional fluorescent signals for identification of surfactants and bacteria
摘要： The imidazolium-pyrene self-assembling nanoprobes can rapidly discriminate four types of surfactants. The surfactants disassembled the probes to turn on significant fluorescence and transform between a pyrene monomer and an excimer, generating a two-dimensional analysis map. The probes were further used to identify different bacterial species.
关键词： fluorescence,surfactants,nanoprobes,self-assembly,bacteria
更新于2025-09-19 17:15:36
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Monodisperse Au@Ag core-shell nanoprobes with ultrasensitive SERS-activity for rapid identification and Raman imaging of living cancer cells
摘要： The rapid identification of living cancer cells is highly crucial for cancer diagnosis, prognosis, and treatment monitoring. However, it is a great challenge to develop an effective way for rapid identification and imaging of cancer cells in a living state. Moreover, synthesis of monodisperse nanoparticles (NPs) with high sensitive surface-enhanced Raman scattering (SERS) activity is also a tough work. Herein, we creatively reported a convenient method to synthesize the novel NPs as the substrate of SERS sensors, which possessed a gold nanobipyramid core and silver nanorod shell. These gold nanobipyramid core and silver nanorod shell NPs (Au NBP@Ag NRs) were further modified with 4-mercaptobenzoicacid (4-MBA, Raman reporter molecule) and then conjugated with reduced bovine serum albumin (rBSA) and folic acid (FA) on their surfaces, to finally acquire Au NBP@Ag NR-MBA-rBSA-FA nanoprobes. In this system, With the enhancement factor (EF) of Au NBP@Ag NRs was about 4 × 10^7, it could significantly enhance Raman signal for Raman reporter molecules, and 4-MBA molecules performed high SERS signals based on their structures; the nanoprobes have favorable specificity and biocompatibility owing to the modification of rBSA which effectively avoided the nonspecific attachment of non-targeted cells. Moreover, the obtained SERS nanoprobes have excellent sensitivity for gastric cancer cells (MGC-803 cells) due to the conjugation of folic acid. Thus, the finally obtained Au NBP@Ag NR-MBA-rBSA-FA nanoprobes possess excellent detection efficiency for living MGC-803 cells. Therefore, our synthesized nanoprobes exhibit ultrasensitive SERS-activity, excellent specificity and superior cancer cells targeting ability, which could be applied for rapid identification and Raman imaging of living cancer cells via the SERS signal detection of the nanoprobes.
关键词： SERS,Au NBP@Ag NR-MBA-rBSA-FA nanoprobes,Living cells imaging,MGC-803
更新于2025-09-19 17:15:36
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Green synthesis of ZnS quantum dot/biopolymer photoluminescent nanoprobes for bioimaging brain cancer cells
摘要： Semiconductor quantum dots (QDs) are one of the most interesting photoluminescent nanomaterials with very promising applications in cancer nanomedicine. In this work, ZnS fluorescent quantum dots (ZnS-QDs) were synthesized and stabilized by carboxymethylcellulose (CMC) as a pH-sensitive biopolymer using a facile one-step green aqueous colloidal process at distinct pH conditions (acidic, neutral and alkaline) and chemical proportions of precursors (Zn2+ and S2?). The optical properties of these nanoconjugates (ZnS@CMC) were characterized by UV–visible and photoluminescence spectroscopy. The morphological features and physicochemical properties were evaluated by TEM, FTIR spectroscopy, zeta potential, and dynamic light scattering (DLS) analyses. The cytocompatibility in vitro of ZnS@CMC was assessed by MTT assay using normal and malignant glioma cells. The UV–Vis results indicated that ZnS-QDs were effectively produced with different bandgap energies (from 4.5 to 3.8 eV) blue-shifted from bulk (Ebulk = 3.61 eV), and sizes (typically from 3.3 to 4.5 nm), dependent on the pH and concentration ratio of precursors during the synthesis. Analogously, the changes of synthesis parameters significantly altered the photoluminescence emission energies and intensities within the visible range of spectra (PL maxima from λ = 400–430 nm, at pH = 3.5, [Zn:S] ratio = 1:2). The cell viability results in vitro (>90%) demonstrated no cytotoxicity of ZnS@CMC nanohybrids towards both cell types. Importantly, these ZnS@CMC nanoconjugates behaved as active fluorescent nanoprobes for bioimaging malignant glioma cells proving the high potential for applications in cancer nanomedicine.
关键词： Fluorescent nanoprobes,Luminescent nanomaterials,ZnS quantum dots,Cancer bioimaging,Green nanotechnology,Luminescent nanoconjugates
更新于2025-09-19 17:13:59
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A boronate-modified molecularly imprinted polymer labeled with a SERS-tag for use in an antibody-free immunoassay for the?carcinoembryonic antigen
摘要： An antibody-free immunoassay that makes use of a boronate affinity molecularly imprinted polymer (MIP) and surface enhanced Raman scattering (SERS) tags is described. It was applied to the specific determination of the carcinoembryonic antigen (CEA) in human serum. For the preparation of the boronate affinity array, a polymer capable of adsorbing glycoproteins was first synthesized on the surface of a glass slide with four spots using 4-vinylbenzeneboronic acid (VPBA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and ethylene glycol and cyclohexanol as porogens. The surface of the VPBA-Co-EGDMA can bind target glycoproteins. After specific capture of the glycoprotein, a “MIP-target glycoprotein-SERS tag” sandwich structure was formed by covalent interaction between the SERS nanotag (consisting of gold nanoparticles and 4-mercaptophenylboronic acid [MPBA]). CEA can be quantified in spiked serum with a detection limit of 0.1 ng·mL?1 via the specific Raman band at 1098 cm?1.
关键词： MIP array,Sandwich structure,Nanoprobes,Biomarker,Real sample analysis
更新于2025-09-12 10:27:22