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An ultrasensitive homogeneous aptasensor for carcinoembryonic antigen based on upconversion fluorescence resonance energy transfer
摘要： Carcinoembryonic antigen (CEA) has been recognized as one of the most important tumor markers. Herein, we reported an ultrasensitive homogeneous aptasensor based on fluorescence resonance energy transfer (FRET) between upconversion nanoparticles (UCNPs) and graphene oxide (GO) for CEA detection. The CEA aptamer modified UCNPs can bind to the surface of GO through π-π stacking interaction, resulting in fluorescence quenching due to the energy transfer from UCNPs to GO. After the introduction of CEA, the CEA aptamer preferentially combined with CEA to form three-dimensional structure which made UCNPs-aptamer dissociate from the GO, blocking the energy transfer process. The fluorescence of UCNPs was accordingly restored in a CEA concentration-dependent manner both aqueous solution and human serum samples. The aptasensor could monitor CEA level directly in human serum and the results were strongly correlated with commercial chemiluminescence kits. The excellent detection performance suggested promising prospect of the aptasensor in practical application.
关键词： Upconversion Nanoparticles,Graphene Oxide,Fluorescence Resonance Energy Transfer,CEA,Aptasensor
更新于2025-09-23 15:21:01
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Evolution of Size and Optical Properties of Upconverting Nanoparticles during High Temperature Synthesis
摘要： We investigated the growth of β-phase NaYF4:Yb3+,Er3+ upconversion nanoparticles synthesized by the thermal decomposition method using a combination of in situ and offline analytical methods for determining the application-relevant optical properties, size, crystal phase, and chemical composition. This included in situ steady state luminescence in combination with offline time-resolved luminescence spectroscopy, as well as small-angle X-ray scattering (SAXS) transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and inductively coupled plasma optical emission spectrometry (ICP-OES). For assessing the suitability of our optical monitoring approach, the in situ collected spectroscopic data, that reveal the luminescence evolution during nanocrystal synthesis, were compared to measurements done after cooling of the reaction mixture of the as-synthesized particles. The excellent correlation of the in situ and time-resolved upconversion luminescence with the nanoparticle sizes determined during the course of the reaction provides important insights into the various stages of nanoparticle growth. This study highlights the capability of in situ luminescence monitoring to control the efficiency of UCNP synthesis, particularly the reaction times at elevated temperatures and the particle quality in terms of size, shape and crystall structure, as well as luminescence lifetime and upconversion quantum yield.
关键词： thermal decomposition,XRD,ICP-OES,TEM,in situ luminescence,SAXS,upconversion nanoparticles
更新于2025-09-23 15:21:01
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Amine-functionalized, porous silica-coated NaYF4:Yb/Er upconversion nanophosphors for efficient delivery of doxorubicin and curcumin
摘要： Upconversion nanoparticles (UCNP) with unique multi-photon excitation photo-luminescence properties have been extensively explored as novel contrast agents for low-background biomedical imaging. There is an increasing interest in employing UCNPs as carrier for drug delivery as these offers a unique opportunity to combine therapy and diagnostics in one platform (theranostics). In the present work, we report microwave-assisted synthesis of hexagonal NaYF4:Yb/Er UCNPs coated with porous silica and functionalized with amine (UCNP@mSiO2). The UCNP@mSiO2 were investigated for controlled delivery of a chemotherapeutic agent, doxorubicin (DOX, hydrophilic), and a chemosensitizing agent, curcumin (CCM, hydrophobic). The drug loading was relatively higher for DOX (17.4%), in comparison to CCM (8.1%). The cumulative drug release from DOX-loaded UCNP@mSiO2 were 30 and 41% at physiological (7.4) and tumoral (6.4) pH, following a pseudo Fickian release pattern, whereas the release from CCM-loaded UCNP@mSiO2 were 27 and 50% at pH 7.4 and 6.4, following a non-Fickian and pseudo-Fickian release patterns. Both DOX and CCM-loaded UCNP@mSiO2 exhibited pH-dependent controlled drug delivery but the effect was more pronounced for CCM, the hydrophobic chemosensitizer. Cell viability assay using HeLa cells showed that DOX-loaded UCNP@mSiO2 inhibit cell growth in a dose-dependent manner, similar to free DOX, but the cell inhibition activity of free CCM was lower than CCM passively entrapped in UCNP@mSiO2. Confocal microscopy studies revealed cell uptake of both the drug by HeLa cells. Thus, UCNP@mSiO2 exhibited the unique capability to deliver hydrophilic and hydrophobic drugs, individually. UCNP@mSiO2 carrier, equipped with theranostic capabilities, may potentially be used for pH-responsive release of chemotherapeutic agents in cancer environment.
关键词： curcumin,porous silica,doxorubicin,drug delivery,Upconversion nanoparticles
更新于2025-09-23 15:21:01
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A DNA‐Azobenzene Nanopump Fueled by Upconversion Luminance for Controllable Intracellular Drug Release
摘要： Stimulus-responsive drug release possesses considerable significance in cancer precise therapy. Inspired by the continuous rotation-inversion movement of photoisomerizable azobenzene (Azo), this work designs an upconversion luminance fueled DNA-Azo nanopump for rapid and efficient drug release. The nanopump is constructed by assembling the Azo-functionalized DNA strands on upconversion nanoparticles (UCNPs). The selective intercalation of doxorubicin (DOX) in specific DNA helix leads to its efficient loading. Under near-infrared light, the UCNPs emit both UV and visible photons to fuel the continuous photo-isomerization of Azo, which acts as an impeller pump to trigger cyclic DNA hybridization and dehybridization for controllable DOX release. In a relatively short period, this system demonstrates 86.7% DOX release. By assembling HIV-1 TAT peptide and hyaluronic acid on the system, cancer cell nuclear targeting delivery is achieved for perinuclear aggregation of DOX and enhanced anticancer therapy. This highly effective drug delivery nanopump would contribute to chemotherapy development.
关键词： upconversion nanoparticles,drug delivery,DNA nanopump,azobenzene
更新于2025-09-19 17:13:59
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A DNA-Azobenzene Nanopump Fueled by Upconversion Luminance for Controllable Intracellular Drug Release
摘要： Stimulus-responsive drug release possesses considerable significance in cancer precise therapy. Inspired by the continuous rotation-inversion movement of photoisomerizable azobenzene (Azo), this work designs an upconversion luminance fueled DNA-Azo nanopump for rapid and efficient drug release. The nanopump is constructed by assembling the Azo-functionalized DNA strands on upconversion nanoparticles (UCNPs). The selective intercalation of doxorubicin (DOX) in specific DNA helix leads to its efficient loading. Under near-infrared light, the UCNPs emit both UV and visible photons to fuel the continuous photo-isomerization of Azo, which acts as an impeller pump to trigger cyclic DNA hybridization and dehybridization for controllable DOX release. In a relatively short period, this system demonstrates 86.7% DOX release. By assembling HIV-1 TAT peptide and hyaluronic acid on the system, cancer cell nuclear targeting delivery is achieved for perinuclear aggregation of DOX and enhanced anticancer therapy. This highly effective drug delivery nanopump would contribute to chemotherapy development.
关键词： upconversion nanoparticles,drug delivery,DNA nanopump,azobenzene
更新于2025-09-19 17:13:59
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Supramolecular Valves Functionalized Rattle-Structured UCNPs@hm-SiO2 Nanoparticles with Controlled Drug Release Triggered by Quintuple Stimuli and Dual-modality Imaging Functions: A Potential Theranostic Nanomedicine
摘要： Integrating multimodality bioimaging and multiple stimuli-responsive controlled drug release properties into one single nanosystem for therapeutic application is highly desirable, but still remains a challenge. Herein, we coated a hollow mesoporous silica shell onto upconversion nanoparticles (UCNPs), conjugated pillarene-based supramolecular valves onto surface of UCNPs@hm-SiO2 using amine-coumarin phototriggers to obtain the multifunctional nanoparticles, UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5]. Benefiting from the core-shell structured UCNPs, the UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5] can serve as the efficient contrast agents for upconversion luminescence and T1-weighted magnetic resonance imaging in vitro/in vivo. More importantly, depending on exquisitely designed supramolecular valves, UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5] can realize zero-premature release under normal physiological conditions (pH 7.4), which produces the minimal damage to normal tissue, whereas this nanosystem can respond to several disease-related signals including acid (most cancers), alkali (metabolic alkalosis), and Zn2+ (Alzheimer’s disease) along with two external stimuli including near infrared (NIR) light and reductive electrical potential via altering spatial structure of pseudorotaxanes, disassembling the molecular stalks, or undergoing photochemical reactions, ultimately resulting in opening of the gatekeepers and release of encapsulated drugs. The multifunctional UCNP-based nanoparticles were endowed with such quintuple stimuli-responsive controlled release characteristics. Specifically, in anticancer application, the rational utilization of the two of them, acid and NIR light, could regulate the release amount and rate of DOX from UCNPs@hm-SiO2-Cou-Cys-DOX/WP[5], accelerate the accumulation of DOX in cell nuclei and thereby promote the cancer cell apoptosis, indicating that the nanomaterials have promising application in cancer treatment. This study provides a novel design strategy for constructing multifunctional UCNP-based nanoparticles with multiple stimuli-responsive drug release features, which have great potential in diagnosis and therapy of relevant diseases as theranostic nanomedicines.
关键词： upconversion nanoparticles,Supramolecular nanovalve,theranostic nanoplatform,quintuple stimuli-responsiveness
更新于2025-09-19 17:13:59
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Resolution and contrast enhancement of laser-scanning multiphoton microscopy using thulium-doped upconversion nanoparticles
摘要： High-contrast optical imaging is achievable using phosphorescent labels to suppress the short-lived background due to the optical backscatter and autofluorescence. However, the long-lived phosphorescence is generally incompatible with high-speed laser-scanning imaging modalities. Here, we show that upconversion nanoparticles of structure NaYF4:Yb co-doped with 8% Tm (8T-UCNP) in combination with a commercial laser-scanning multiphoton microscopy are uniquely suited for labeling biological systems to acquire high-resolution images with the enhanced contrast. In comparison with many phosphorescent labels, the 8T-UCNP emission lifetime of ~ 15 μs affords rapid image acquisition. The high-order optical nonlinearity of the 8T-UCNP (n ≈ 4, as confirmed experimentally and theoretically) afforded pushing the resolution limit attainable with UCNPs to the diffraction-limit. The contrast enhancement was achieved by suppressing the background using (i) bandpass spectral filtering of the narrow emission peak of 8T-UCNP at 455-nm, and (ii) time-gating implemented with a time-correlated single-photon counting system that demonstrated the contrast enhancement of > 2.5-fold of polyethyleneimine-coated 8T-UCNPs taken up by human breast adenocarcinoma cells SK-BR-3. As a result, discrete 8T-UCNP nanoparticles became clearly observable in the freshly excised spleen tissue of laboratory mice 15-min post intravenous injection of an 8T-UCNP solution. The demonstrated approach paves the way for high-contrast, high-resolution, and high-speed multiphoton microscopy in challenging environments of intense autofluorescence, exogenous staining, and turbidity, as typically occur in intravital imaging.
关键词： time-correlated single photon counting,time-gated imaging,scanning microscopy,autofluorescence,upconversion nanoparticles
更新于2025-09-19 17:13:59
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Thermoplasmonic Maskless Lithography on Upconverting Nanocomposites Assisted by Gold Nanostars
摘要： Photothermal effects in plasmonic nanoparticles can be used to locally modify temperature-sensitive materials. Polylactic acid (PLA) is a thermoplastic biodegradable polymer with a glass transition temperature around 60 ?C that has been popularized as a feedstock material for 3D printing. Here, we extend its use to produce thin PLA films that can be modified at the microscopic level when covered with gold nanostars (AuNSs). The heat dissipation generated when exciting the plasmon resonance of AuNSs, under exposure to 976 nm focused laser light, produce an increase in the local temperature of more than 100 ?C. When the temperature surpasses the glass transition of the base PLA layer, AuNSs get attached to the polymer surface. The following dissolution of the unexposed material in acetone bath permits the precise control of the engraving process at the microscale. Furthermore, Er3+ doped upconverting nanoparticles embedded into the PLA layer can act as optical nanothermometers to probe the local temperature, simultaneously allowing the visualization of the laser spot. A computer numerical control (CNC) system was developed to drive the laser writing beam and transfer 2D patterns, opening up the thermoplasmonic maskless lithography technique. Suitable for rigid and flexible substrates coated with PLA, the methods and materials developed here were applied to produce patterned substrates for surface enhanced Raman spectroscopy, and luminescent optical encoding for anti-counterfeiting technologies.
关键词： photothermal nanoparticles,gold nanostars,optical thermometry,thermoplasmonics,maskless lithography,upconversion nanoparticles
更新于2025-09-16 10:30:52
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Ultrasensitive broadband photodetector using electrostatically conjugated MoS2-upconversion nanoparticle nanocomposite
摘要： Hybrid or composite nanomaterials have emerged that demonstrates superior optoelectronic performance over pure nanomaterials that lacks broadband usage, or responsivity, or both, mainly because of the limitation of the collection of photogenerated carriers. We have addressed this problem by using a composite of MoS2 and a multi-photon absorbing lanthanide doped upconversion nanoparticles (UCNPs), that emits in the visible, to make a photodetector (PD) device with ultrahigh broadband responsivity. Single flake MoS2 electrostatically conjugated with UCNPs were used to fabricate the PD device with platinum, and gold contacts. The device was irradiated with UV-to-NIR illumination, at different power density, to study its broadband photosensitivity. Photoresponsivities in excess of 100 AW-1 is easily obtained; a highest responsivity of 1254 AW-1 is reported for 980 nm at 1.0 V bias. An unprecedented normalized gain of 7.12 x 10-4 cm2 V-1, and Detectivity of 1.05 x 1015 Jones (@980 nm, 1V) was obtained which is, to the best of our knowledge, the highest reported till date for this device class. Under vacuum conditions even higher values of these device parameters were obtained, while losing on the response speeds. The photoresponsivity in the nanocomposite followed the trend of the convoluted optical absorption of the individual components. Real application of the PD device was demonstrated using non-laser domestic appliances such as sodium vapour lamp, mobile phone flash light, and air-condition remote controller.
关键词： Nanocomposites,Responsivity,Molybdenum disulphide,Photodetectors,Broadband,Upconversion nanoparticles
更新于2025-09-16 10:30:52
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Controlled patterning of upconversion nanocrystals through capillary force
摘要： Lanthanide-doped upconversion nanoparticles (UCNPs) can absorb near-infrared photons and convert them into visible and ultraviolet emissions. These nanomaterials possess extraordinary optical performance and hold potential as active platforms for a variety of technological applications. The ability to fabricate highly ordered nanoparticle-based photonic elements over a large area is of fundamental significance for luminescence tuning. Despite all the efforts made, however, large-area spatial patterning of UCNPs into ordered arrays with high controllability remains a challenge. In this study, we report a high-throughput strategy to pattern optical nanomaterials through the use of polymer microspheres and templated assembly of UCNPs. This technique utilizes capillary force to drive hybrid clusters into the physical template, resulting in large-area, spatially ordered arrays of particles. The findings reported in this work may promote the development of novel nonlinear optical devices, such as solid-state laser arrays, high-density optical storage, and anti-counterfeiting labels.
关键词： self-assembly,rare earths,patterning,upconversion nanoparticles
更新于2025-09-16 10:30:52