A method to control the size of nanoscale silicon grown in thermally annealed hydrogenated amorphous silicon （a-Si：H） films is reported. Using the characterizing techniques of micro-Raman scattering, X-ray diffract...A method to control the size of nanoscale silicon grown in thermally annealed hydrogenated amorphous silicon （a-Si：H） films is reported. Using the characterizing techniques of micro-Raman scattering, X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate in thermally annealing the a-Si ： H films. When the a-Si：H films have been annealed with high rising rate（～100℃/s）, the sizes of nanoscale silicon particles are in the range of 1.6～15nm. On the other hand, if the a-Si：H films have been annealed with low temperature rising rate（～1℃/s）, the sizes of nanoscale silicon particles are in the range of 23～46nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of the formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for visible light emission, authors have not detected any visible photoluminescence（PL） from these nc-Si clusters before surface passivation. After electrochemical oxidization in hydrofluoric acid, however, intense red PL has been detected. Cyclic hydrofluoric oxidization and air exposure can cause subsequent blue shift in the red emission. The importance of surface passivation and quantum confinement in the visible emissions has been discussed.展开更多
The luminescent properties of terbium complex (terbium citrate) by binding to silver nanopartilces in the solution have been reported in this paper.The enhanced luminescence of the complex containing silver nanopartic...The luminescent properties of terbium complex (terbium citrate) by binding to silver nanopartilces in the solution have been reported in this paper.The enhanced luminescence of the complex containing silver nanoparticles was observed at a limited particle concentration region.The nanoparticle concentration dependence of the luminescent intensity was regarded as the result of a delicate balance between an enhancing and a quenching effect of the silver nanoparticles.Furthermore,silver nanoparticles also affected the asymmetric ratio (AS) value of terbium luminescence.We discuss the luminescent properties of the terbium complex in terms of the local electromagnetic field,refractive index,and the ligand field around terbium ion.展开更多
In this work, the intensification of luminol electrochemiluminescence (ECL) by metallic oxide nanoparticles (MONPs), as ZnO, MnO2,In2O3 and TiO2 , under alkaline condition is reported and the related mechanism is stud...In this work, the intensification of luminol electrochemiluminescence (ECL) by metallic oxide nanoparticles (MONPs), as ZnO, MnO2,In2O3 and TiO2 , under alkaline condition is reported and the related mechanism is studied. It is found that all four types of those MONPs exhibit the effect toward the ECL intensification of luminol. Furthermore, the silica sol-gel film is taken to immobilize the MONPs onto the platinum electrodes. The so-obtained modified electrodes also show the enhanced ECL and better signal/noise ratio, as well improved signal stability. Finally, the ECL reagent, luminol, is immobilized together with the MONPs onto the electrode surface to perform as the ECL sensor. On resulting sensors, good linear responses are obtained toward hydrogen peroxide. The mechanism of intensification of luminol ECL by MONPs is discussed in this paper. It is proposed that the ECL intensification can be attributed to the production of reactive oxygen species, as well as the adsorption of luminol on surface of MONPs.展开更多
The coupling of upconversion nanophosphors （UCNPs） with the surface plasmonic resonance （SPR） of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achi...The coupling of upconversion nanophosphors （UCNPs） with the surface plasmonic resonance （SPR） of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achieve stable, reproducible and effective upconversion luminescence （UCL） enhancement through such coupling. In this work, we present a novel strategy to improve UCL of NaYF4：ybB,Er3. UCNPs, by combining the near-field coupling of SPR of silver and the far-field coupling of poly（methyl methacrylate） （PMMA） opal photonic crystals （OPCs） with the UCNPs. In order to control the effective interaction distance between the UCNPs and the SPR, a porous silver film consisting of randomly distributed silver nanoparticles （NPs） （〉 100 nm） was prepared which demonstrated strong SPR over a broad wavelength range, and its coupling to the UCNPs was found to be much stronger than that of a dense film. In the far-field coupling of OPCs, the photonic stop band （PSB） of the PMMA OPCs was tuned to 980 nm, matching exactly the excitation light. By modulating the particle size of the UCNPs, and the direction and excitation power of the incident light, a maximum enhancement of 60-fold was observed, which is an important advance for metaMnduced UCL enhancement systems.展开更多
The synthesis of amphiphilic aggregation-induced emission （ALE） dyes based organic nanoparticles has recently attracted in- creasing attention in the biomedical fields. These AlE dyes based nanoparticles could effec...The synthesis of amphiphilic aggregation-induced emission （ALE） dyes based organic nanoparticles has recently attracted in- creasing attention in the biomedical fields. These AlE dyes based nanoparticles could effectively overcome the aggregation caused quenching effect of conventional organic dyes, making them promising candidates for fabrication of ultrabright organic luminescent nanomaterials. In this work, AIE-active luminescent polymeric nanoparticles （4-NH2-PEG-TPE-E LPNs） were facilely fabricated through Michael addition reaction between tetraphenylethene acrylate （TPE-E） and 4-arm-poly（ethylene glycol）-amine （4-NH2-PEG） in rather mild ambient. The 4-NH2-PEG can not only endow these AlE-active LPNs good water dispersibility, but also provide functional groups for further conjugation reaction. The size, morphology and luminescent prop- erties of 4-NH2-PEG-TPE-E LPNs were characterized by a series of techniques in detail. Results suggested that these AlE-active LPNs showed spherical morphology with diameter about 100-200 nm. The obtained 4-NH2-PEG-TPE-E LPNs display high water dispersibility and strong fluorescence intensity because of their self assembly and AlE properties of TPE-E. Biological evaluation results demonstrated that 4-NH2-PEG-TPE-E LPNs showed negative toxicity toward cancer cells and good fluorescent imaging performance. All of these features make 4-NHz-PEG-TPE-E LPNs promising candidates for biolog- ical imaging and therapeutic applications.展开更多
A novel electrogenerated chemiluminescence （ECL） aptasensor for highly sensitive detection of thrombin was developed on the basis of poly（pyrrole-co-pyrrole propylic acid） nanoparticles loaded with aptamer and rut...A novel electrogenerated chemiluminescence （ECL） aptasensor for highly sensitive detection of thrombin was developed on the basis of poly（pyrrole-co-pyrrole propylic acid） nanoparticles loaded with aptamer and ruthenium complex. Thrombin binding aptamers served as the molecular recognition elements and ruthenium bis（2,2＇-bipyridine） （2,2＇-bipyridine-4,4＇-dicarboxylic acid）-ethylenediamine （Rul） was used as an ECL signal complex. Novel electroactive polymers poly（pyrrole-co-pyr- role propylic acid） nanoparticles （Ppy-pa NPs） were synthesized by a simple alcohol-assisted microemulsion polymerization. Rul-Ppy-pa NPs were synthesized by covalently coupling Rul with the Ppy-pa NPs. Ppy-pa NPs and Rul-Ppy-pa NPs were characterized using a fourier transform infrared spectrometer, super-conducting fourier digital NMR spectrometer, and trans- mission electron microscope. One ECL chemical sensor fabricated by immobilizing the Rul-Ppy-pa NPs on PIGE was developed for the determination of TprA with a high sensitivity and stability. The ECL aptasensor was fabricated by covalenfly coupling the thrombin binding aptamer-I （TBA-I） onto the surface of the paraffin-impregnated graphite electrode, which had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations, for capturing thrombin onto the electrode and then the TBA-II labeled with Rul-Ppy-pa NPs was bound with epitope of thrombin. The ECL aptasensot showed an extremely low detection limit of 3.0×10^-16 mol/L for thrombin and a good selectivity. This work demonstrated that using Ppy-pa NPs as a carrier of ruthenium complex and molecular recognition element was a promising approach for the fabrication of ECL biosensor with high sensitivity.展开更多
Multimodal imaging nanoprobes are urgently sought because they can integrate different imaging func- tion into individual nanoplatform and provide more comprehensive and accurate information for the diagnosis of early...Multimodal imaging nanoprobes are urgently sought because they can integrate different imaging func- tion into individual nanoplatform and provide more comprehensive and accurate information for the diagnosis of early-stage tumor. Lanthanide-based upconversion nanoparticles （UCNPs） are regarded as promising nanoplatforms to fabricate these probes. Herein, we firstly developed the active core-active shell structured NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs with the average diameter of 13.23 ＋ 0.96 nm as multimodal imaging probes. These water-dispersible nanoprobes presented excellent near-infrared to near-infrared （NIR-to-NIR） upconversion luminescence （UCL） performance, which is favorable for optical bioimaging due to deeper tissue penetration and autofluorescence reduction. After coated with the NaGdF4：Yb active shell, the UCL emission intensity at 800 nm increased by 7.2 times. These nanoprobes exhibited a desirable longitudinal relaxivity （rl = 3.58 L/（mmol s）） and strong X-ray attenuation property （58.84 HU L/g）. The cytotoxicity assessment, histology analysis and biodistribution study revealed that NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs had relatively low cytotoxicity and negligible organ toxicity. These UCNPs were applied for NIR-to-NIR UCL imaging in vivo. More importantly, the detection of small tumor was successfully achieved under Trweighted MRI and CT imaging modalities after intravenous injection of these UCNPs. These results revealed that NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs could serve as promising NIR-to-NIR UCL/MRI/CT trimodal imaging probes.展开更多
文摘A method to control the size of nanoscale silicon grown in thermally annealed hydrogenated amorphous silicon （a-Si：H） films is reported. Using the characterizing techniques of micro-Raman scattering, X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate in thermally annealing the a-Si ： H films. When the a-Si：H films have been annealed with high rising rate（～100℃/s）, the sizes of nanoscale silicon particles are in the range of 1.6～15nm. On the other hand, if the a-Si：H films have been annealed with low temperature rising rate（～1℃/s）, the sizes of nanoscale silicon particles are in the range of 23～46nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of the formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for visible light emission, authors have not detected any visible photoluminescence（PL） from these nc-Si clusters before surface passivation. After electrochemical oxidization in hydrofluoric acid, however, intense red PL has been detected. Cyclic hydrofluoric oxidization and air exposure can cause subsequent blue shift in the red emission. The importance of surface passivation and quantum confinement in the visible emissions has been discussed.
文摘The luminescent properties of terbium complex (terbium citrate) by binding to silver nanopartilces in the solution have been reported in this paper.The enhanced luminescence of the complex containing silver nanoparticles was observed at a limited particle concentration region.The nanoparticle concentration dependence of the luminescent intensity was regarded as the result of a delicate balance between an enhancing and a quenching effect of the silver nanoparticles.Furthermore,silver nanoparticles also affected the asymmetric ratio (AS) value of terbium luminescence.We discuss the luminescent properties of the terbium complex in terms of the local electromagnetic field,refractive index,and the ligand field around terbium ion.
基金supported by the National Natural Science Foundation of China (20275025 & 20675055)the Natural Science Foundation of Jiangsu Province (BK2009111)Technology Plan of Suzhou (SYJG0901)
文摘In this work, the intensification of luminol electrochemiluminescence (ECL) by metallic oxide nanoparticles (MONPs), as ZnO, MnO2,In2O3 and TiO2 , under alkaline condition is reported and the related mechanism is studied. It is found that all four types of those MONPs exhibit the effect toward the ECL intensification of luminol. Furthermore, the silica sol-gel film is taken to immobilize the MONPs onto the platinum electrodes. The so-obtained modified electrodes also show the enhanced ECL and better signal/noise ratio, as well improved signal stability. Finally, the ECL reagent, luminol, is immobilized together with the MONPs onto the electrode surface to perform as the ECL sensor. On resulting sensors, good linear responses are obtained toward hydrogen peroxide. The mechanism of intensification of luminol ECL by MONPs is discussed in this paper. It is proposed that the ECL intensification can be attributed to the production of reactive oxygen species, as well as the adsorption of luminol on surface of MONPs.
文摘The coupling of upconversion nanophosphors （UCNPs） with the surface plasmonic resonance （SPR） of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achieve stable, reproducible and effective upconversion luminescence （UCL） enhancement through such coupling. In this work, we present a novel strategy to improve UCL of NaYF4：ybB,Er3. UCNPs, by combining the near-field coupling of SPR of silver and the far-field coupling of poly（methyl methacrylate） （PMMA） opal photonic crystals （OPCs） with the UCNPs. In order to control the effective interaction distance between the UCNPs and the SPR, a porous silver film consisting of randomly distributed silver nanoparticles （NPs） （〉 100 nm） was prepared which demonstrated strong SPR over a broad wavelength range, and its coupling to the UCNPs was found to be much stronger than that of a dense film. In the far-field coupling of OPCs, the photonic stop band （PSB） of the PMMA OPCs was tuned to 980 nm, matching exactly the excitation light. By modulating the particle size of the UCNPs, and the direction and excitation power of the incident light, a maximum enhancement of 60-fold was observed, which is an important advance for metaMnduced UCL enhancement systems.
基金supported by the National Natural Science Foundation of China (21134004, 21201108, 51363016, 21474057, 21564006, 21561022)the National Basic Research Program (2011CB935700)
文摘The synthesis of amphiphilic aggregation-induced emission （ALE） dyes based organic nanoparticles has recently attracted in- creasing attention in the biomedical fields. These AlE dyes based nanoparticles could effectively overcome the aggregation caused quenching effect of conventional organic dyes, making them promising candidates for fabrication of ultrabright organic luminescent nanomaterials. In this work, AIE-active luminescent polymeric nanoparticles （4-NH2-PEG-TPE-E LPNs） were facilely fabricated through Michael addition reaction between tetraphenylethene acrylate （TPE-E） and 4-arm-poly（ethylene glycol）-amine （4-NH2-PEG） in rather mild ambient. The 4-NH2-PEG can not only endow these AlE-active LPNs good water dispersibility, but also provide functional groups for further conjugation reaction. The size, morphology and luminescent prop- erties of 4-NH2-PEG-TPE-E LPNs were characterized by a series of techniques in detail. Results suggested that these AlE-active LPNs showed spherical morphology with diameter about 100-200 nm. The obtained 4-NH2-PEG-TPE-E LPNs display high water dispersibility and strong fluorescence intensity because of their self assembly and AlE properties of TPE-E. Biological evaluation results demonstrated that 4-NH2-PEG-TPE-E LPNs showed negative toxicity toward cancer cells and good fluorescent imaging performance. All of these features make 4-NHz-PEG-TPE-E LPNs promising candidates for biolog- ical imaging and therapeutic applications.
基金supported by the National Natural Science Foundation of China (21027007, 20975065 & 20775046)
文摘A novel electrogenerated chemiluminescence （ECL） aptasensor for highly sensitive detection of thrombin was developed on the basis of poly（pyrrole-co-pyrrole propylic acid） nanoparticles loaded with aptamer and ruthenium complex. Thrombin binding aptamers served as the molecular recognition elements and ruthenium bis（2,2＇-bipyridine） （2,2＇-bipyridine-4,4＇-dicarboxylic acid）-ethylenediamine （Rul） was used as an ECL signal complex. Novel electroactive polymers poly（pyrrole-co-pyr- role propylic acid） nanoparticles （Ppy-pa NPs） were synthesized by a simple alcohol-assisted microemulsion polymerization. Rul-Ppy-pa NPs were synthesized by covalently coupling Rul with the Ppy-pa NPs. Ppy-pa NPs and Rul-Ppy-pa NPs were characterized using a fourier transform infrared spectrometer, super-conducting fourier digital NMR spectrometer, and trans- mission electron microscope. One ECL chemical sensor fabricated by immobilizing the Rul-Ppy-pa NPs on PIGE was developed for the determination of TprA with a high sensitivity and stability. The ECL aptasensor was fabricated by covalenfly coupling the thrombin binding aptamer-I （TBA-I） onto the surface of the paraffin-impregnated graphite electrode, which had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations, for capturing thrombin onto the electrode and then the TBA-II labeled with Rul-Ppy-pa NPs was bound with epitope of thrombin. The ECL aptasensot showed an extremely low detection limit of 3.0×10^-16 mol/L for thrombin and a good selectivity. This work demonstrated that using Ppy-pa NPs as a carrier of ruthenium complex and molecular recognition element was a promising approach for the fabrication of ECL biosensor with high sensitivity.
基金supported by the National Natural Science Foundation of China(21003013)the Jilin Province Science and Technology Development Project(No.20170101094JC)the Scientific Research Fund of Jilin Provincial Education Department (2016323)
文摘Multimodal imaging nanoprobes are urgently sought because they can integrate different imaging func- tion into individual nanoplatform and provide more comprehensive and accurate information for the diagnosis of early-stage tumor. Lanthanide-based upconversion nanoparticles （UCNPs） are regarded as promising nanoplatforms to fabricate these probes. Herein, we firstly developed the active core-active shell structured NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs with the average diameter of 13.23 ＋ 0.96 nm as multimodal imaging probes. These water-dispersible nanoprobes presented excellent near-infrared to near-infrared （NIR-to-NIR） upconversion luminescence （UCL） performance, which is favorable for optical bioimaging due to deeper tissue penetration and autofluorescence reduction. After coated with the NaGdF4：Yb active shell, the UCL emission intensity at 800 nm increased by 7.2 times. These nanoprobes exhibited a desirable longitudinal relaxivity （rl = 3.58 L/（mmol s）） and strong X-ray attenuation property （58.84 HU L/g）. The cytotoxicity assessment, histology analysis and biodistribution study revealed that NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs had relatively low cytotoxicity and negligible organ toxicity. These UCNPs were applied for NIR-to-NIR UCL imaging in vivo. More importantly, the detection of small tumor was successfully achieved under Trweighted MRI and CT imaging modalities after intravenous injection of these UCNPs. These results revealed that NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs could serve as promising NIR-to-NIR UCL/MRI/CT trimodal imaging probes.
