Co-reporter:Zhenluan Xue, Xiaolong Li, Youbin Li, Mingyang Jiang, Hongrong Liu, Songjun Zeng, and Jianhua Hao
ACS Applied Materials & Interfaces July 12, 2017 Volume 9(Issue 27) pp:22132-22132
Publication Date(Web):June 12, 2017
DOI:10.1021/acsami.7b03802
Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) are considered as new alternative optical probes due to being free of autofluorescence, benefited from the self-sustained emission after excitation and high signal-to-noise ratio. However, the NIR-emitted PLNPs always present a short decay time and require excitation by ultraviolet or visible light with a short penetrable depth, remarkably hindering their applications for in vivo long-term tracking and imaging. Therefore, it is important to develop NIR-emitted PLNPs with in vivo activation nature by new excitation sources with deeper penetrating depths. Here, we propose a new type of X-ray-activated ZnGa2O4:Cr PLNPs (X-PLNPs) with efficient NIR persistent emission and rechargeable activation features, in which both the excitation and emission possess a high penetrable nature in vivo. These X-PLNPs exhibit long-lasting, up to 6 h, NIR emission at 700 nm after the stoppage of the X-ray excitation source. More importantly, the designed X-PLNPs can be readily reactivated by a soft X-ray excitation source with low excitation power (45 kVp, 0.5 mA) to restore in vivo bioimaging signals even at 20 mm depth. Renewable in vivo whole-body bioimaging was also successfully achieved via intravenous injection/oral administration of X-PLNPs after in situ X-ray activation. This is the first time that NIR-emitted PLNPs have been demonstrated to be recharged by X-ray light for deep-tissue in vivo bioimaging, which paves the way for in vivo renewable bioimaging using PLNPs and makes the PLNPs more competitive in bioimaging area.Keywords: biodistribution; in vivo rechargeable bioimaging; NIR persistent luminescence; X-ray excitation; X-ray-activated NIR persistent bioimaging;
Co-reporter:Zhenluan Xue;Xiaolong Li;Youbin Li;Mingyang Jiang;Guozhong Ren;Hongrong Liu;Jianhua Hao
Nanoscale (2009-Present) 2017 vol. 9(Issue 21) pp:7276-7283
Publication Date(Web):2017/06/01
DOI:10.1039/C6NR09716B
Long-lasting persistent luminescent nanoparticles (PLNPs) with efficient near-infrared (NIR) emission have emerged as a new generation of probes for in vivo optical bioimaging owing to their advantages of zero-autofluorescence benefited from the self-sustained emission after excitation, deep penetration depth, and a high signal-to-noise ratio. However, most of the PLNPs are charged by ultraviolet (UV) or visible light, remarkably limiting their applications for in vivo long-term bioimaging. Here we demonstrate 980 nm laser activated upconversion-PLNPs (UC-PLNPs) with efficient NIR emission. The NIR-emitting UC-PLNPs (Zn3Ga2GeO8:Yb/Er/Cr) were synthesized by a sol–gel method with subsequent calcination. Owing to the efficient energy-transfer between Er and Cr ions, these UC-PLNPs present long-lasting up to 15 h NIR emission at 700 nm after the excitation of a 980 nm laser; in which both excitation and emission bands fall within the biological transparent window. The results of in vitro/in vivo toxicity assessments indicate that UC-PLNPs after surface modification present low biotoxicity and side effects in living animals. More importantly, the synthesized UC-PLNPs can be effectively recharged by 980 nm laser to restore in vivo persistent bioimaging signals and can also be employed as nanoprobes for in vivo UC optical bioimaging. This is the first demonstration of rechargeable UC-PLNPs for NIR-to-NIR in vivo bioimaging. We believe that the synthesized UC-PLNPs by combining UC and persistent luminescence properties into a single host may have potential applications in the bioimaging area and pave the way for widely using PLNPs for in vivo renewable long-lasting bioimaging.
Co-reporter:Youbin Li;Xiaolong Li;Zhenluan Xue;Mingyang Jiang;Jianhua Hao
Advanced Healthcare Materials 2017 Volume 6(Issue 10) pp:
Publication Date(Web):2017/05/01
DOI:10.1002/adhm.201601231
Doping has played a vital role in constructing desirable hybrid materials with tunable functions and properties via incorporating atoms into host matrix. Herein, a simple strategy for simultaneously modifying the phase, size, and upconversion luminescence (UCL) properties of the NaLnF4 (Ln = Y, Yb) nanocrystals by high-temperature coprecipitation through nonequivalent M2+ doping (M = Mg2+, Co2+) has been demonstrated. The phase transformation from cubic to hexagonal is readily achieved by doping M2+. Compared with Mg-free sample, a remarkable enhancement of overall UCL (≈27.5 times) is obtained by doping Mg2+. Interestingly, owing to the efficient UCL, red UCL-guided tiny tumor (down to 3 mm) diagnosis is demonstrated for the first time. The results open up a new way of designing high efficient UCL probe with combination of hexagonal phase and small size for tiny tumor detection.
Co-reporter:Zhigao Yi, Xiaolong Li, Wei Lu, Hongrong Liu, Songjun Zeng and Jianhua Hao
Journal of Materials Chemistry A 2016 vol. 4(Issue 15) pp:2715-2722
Publication Date(Web):22 Mar 2016
DOI:10.1039/C5TB02375K
Lanthanide nanoparticles (NPs), which are known as upconversion fluorescence probes for multimodal bioimaging, including magnetic resonance imaging (MRI), have attracted much attentions. In MRI, conventional contrast agents are generally employed separately in a single type of MRI. T1- and T2-weighted MRI alone have unique limitations; therefore, it is urgently necessary to combine the two modalities so as to be able to provide more comprehensive and synergistic diagnostic information than the single modality of MRI. Unfortunately, there is a lack of advanced materials as enhancing agents which are fully suitable for bimodal MRI. Here, we report a new class of hybrid lanthanide nanoparticles as synergistic contrast agents in T1/T2 dual-weighted MRI and imaging-directed tumor diagnosis. The r2/r1 value of BaGdF5 NPs can be readily adjusted from 2.8 to 334.8 by doping with 0%, 50%, or 100% Ln3+ (Ln3+ = Yb3+, Er3+, or Dy3+), respectively. Among these, BaGdF5:50% Er3+ NPs were successfully used as binary contrast agents for T1/T2 dual-weighted MRI and synergistic tumor diagnosis in vivo. These findings reveal that the longitudinal and transverse relaxivities of these Gd3+-based NPs can be controlled by tuning the Ln3+ dopants and their concentrations, providing a simple and general method for designing simultaneous T1/T2 enhancing agents.
Co-reporter:Zhigao Yi;Xiaolong Li;Zhenluan Xue;Xiao Liang;Wei Lu;Hao Peng;Hongrong Liu;Jianhua Hao
Advanced Functional Materials 2015 Volume 25( Issue 46) pp:7119-7129
Publication Date(Web):
DOI:10.1002/adfm.201503672
Effective nanoprobes and contrast agents are urgently sought for early-stage cancer diagnosis. Upconversion nanoparticles (UCNPs) are considerable alternatives for bioimaging, cancer diagnosis, and therapy. Yb3+/Tm3+ co-doping brings both emission and excitation wavelengths into the near-infrared (NIR) region, which is known as “optical transmission window” and ideally suitable for bioimaging. Here, NIR emission intensity is remarkably enhanced by 113 times with the increase of Yb3+ concentration from 20% to 98% in polyethylene glycol (PEG) modified NaYF4:Yb3+/Tm3+ UCNPs. PEG-UCNPs-5 (98% Yb3+) can act as excellent nanoprobes and contrast agents for trimodal upconversion (UC) optical/CT/T2-weighted magnetic resonance imaging (MRI). In addition, the enhanced detection of lung in vivo long-lasting tracking, as well as possible clearance mechanism and excretion routes of PEG-UCNPs-5 have been demonstrated. More significantly, a small tumor down to 4 mm is detected in vivo via intravenous injection of these nanoprobes under both UC optical and T2-weighted MRI modalities. PEG-UCNPs-5 can emerge as bioprobes for multi-modal bioimaging, disease diagnosis, and therapy, especially the early-stage tumor diagnosis.
Co-reporter:Zhigao Yi, Wei Lu, Hongrong Liu and Songjun Zeng
Nanoscale 2015 vol. 7(Issue 2) pp:542-550
Publication Date(Web):21 Nov 2014
DOI:10.1039/C4NR05161K
Polyacrylic acid (PAA) modified NaYF4:Gd/Yb/Er upconversion nanorods (denoted as PAA-UCNRs) are demonstrated for tri-modal upconversion (UC) optical, computed X-ray tomography (CT), and magnetic resonance imaging (MRI). The hydrophilic PAA-UCNRs were obtained from hydrophobic oleic acid (OA) capped UCNRs (denoted as OA-UCNRs) using a ligand exchange method. The as-prepared UCNRs with a hexagonal phase structure present high monodispersity. These PAA-UCNRs are successfully used as ideal probes for in vivo UC luminescence bioimaging and synergistic X-ray and UC bioimaging. Moreover, X-ray CT imaging reveals that PAA-UCNRs can act as contrast agents for improved detection of the liver and spleen. In addition, a significant signal enhancement in the liver is observed in in vivo MRI, indicating that PAA-UCNRs are ideal T1-weighted MRI agents. More importantly, in vivo long-term tracking based on these PAA-UCNRs in the live mice and the corresponding ex vivo bioimaging of isolated organs also verify the translocation of PAA-UCNRs from the liver to the spleen, and the observed intense UC signals from the feces reveal the biliary excretion mechanism of these UCNRs. These findings contribute to understanding of the translocation and potential route for excretion of PAA-UCNRs, which can provide an important guide for the diagnosis and detection of diseases based on these UCNRs.
Co-reporter:Zhigao Yi, Wei Lu, Songjun Zeng, Haibo Wang, Ling Rao, Zheng Li
Journal of Alloys and Compounds 2015 Volume 637() pp:489-496
Publication Date(Web):15 July 2015
DOI:10.1016/j.jallcom.2015.03.045
•Tb3+/Dy3+/Mn2+ doped CePO4 DCNPs were prepared by a one-pot hydrothermal process.•The PL properties and the ET mechanism of these DCNPs were investigated in detail.•These DCNPs exhibit tunable multi-color output under UV excitation.•Intense white emissions can be realized by singly doping Dy3+ and Mn2+ in CePO4 host.In this paper, a series of Tb3+/Dy3+/Mn2+ doped CePO4 downconversion nanophosphors (DCNPs) were prepared by a one-pot hydrothermal process. The obtained DCNPs presented monoclinic and hexagonal phase structure with wire-like shape. The photoluminescence (PL) properties and the energy transfer (ET) mechanism of these DCNPs were investigated in detail. The ET mechanism of Ce3+/Tb3+ in CePO4 host was calculated by means of concentration quenching and spectral overlapping, and calculation results revealed that dipole–dipole interactions should be more responsible. The maximum value of ET efficiency was measured to 87.4% for Tb3+ doped CePO4 system. In addition, owing to the efficient ET between Ce3+ and Tb3+/Dy3+/Mn2+, these as-prepared DCNPs exhibit tunable multi-color output under ultra-violet (UV) light excitation. More importantly, the intense cold and warm white emissions can be realized by singly doping 2%Dy3+ and 20%Mn2+ in CePO4 host under UV irradiation, respectively. The corresponding CIE 1931 coordinates were calculated to be (0.30, 0.30) and (0.30, 0.32), respectively, which are closed to the standard white emission (0.33, 0.33). These findings demonstrate the efficient white light emission by singly doped Dy3+ or Mn2+ in CePO4 system for the first time, which is different from commonly used co-doped or tri-doped system. The multicolor tuning and white emission make these Tb3+/Dy3+/Mn2+ doped CePO4 DCNPs potential phosphors in the fields of displays, lighting, and field-emission devices.
Co-reporter:Songjun Zeng;Zhigao Yi;Wei Lu;Chao Qian;Haibo Wang;Ling Rao;Tianmei Zeng;Hongrong Liu;Huijing Liu;Bin Fei;Jianhua Hao
Advanced Functional Materials 2014 Volume 24( Issue 26) pp:4051-4059
Publication Date(Web):
DOI:10.1002/adfm.201304270
A strategy is demonstrated for simultaneous phase/size manipulation, multicolor tuning, and remarkably enhanced upconversion luminescence (UCL), particularly in red emission bands in fixed formulae of general lanthanide-doped upconverting nanoparticles (UCNPs), namely NaLnF4:Yb/Er (Ln: Lu, Gd, Yb), simply through transition metal Mn2+-doping. The addition of different Mn2+ dopant contents in NaLnF4:Yb/Er system favors the crystal structure changing from hexagonal (β) phase to cubic (α) phase, and the crystal size of UCNPs can be effectively controlled. Moreover, the UCL can be tuned from green through yellow and to dominant red emissions under the excitation of 980 nm laser. Interestingly, a large enhancement in overall UCL spectra of Mn2+ doped UCNPs (∼59.1 times for NaLuF4 host, ∼39.3 times for NaYbF4 host compared to the UCNPs without Mn2+ doping) is observed, mainly due to remarkably enhanced luminescence in the red band. The obtained result greatly benefits in vitro and in vivo upconversion bioimaging with highly sensitive and deeper tissue penetration. To prove the application, a select sample of nanocrystal is used as an optical probe for in vitro cell and in vivo bioimaging to verify the merits of high contrast, deeper tissue penetration, and the absence of autofluorescence. Furthermore, the blood vessel of lung of a nude mouse with the injection of Mn2+-doped NaLuF4: Yb/Er UCNPs can be readily visualized using X-ray imaging. Therefore, the Mn2+ doping method provides a new strategy for phase/size control, multicolor tuning, and remarkable enhancement of UCL dominated by red emission, which will impact on the field of bioimaging based on UCNP nanoprobes.
Co-reporter:Haibo Wang, Wei Lu, Tianmei Zeng, Zhigao Yi, Ling Rao, Hongrong Liu and Songjun Zeng
Nanoscale 2014 vol. 6(Issue 5) pp:2855-2860
Publication Date(Web):20 Dec 2013
DOI:10.1039/C3NR05782H
In this paper, multi-functional hexagonal phase NaErF4:Yb nanorods were synthesized by a facile hydrothermal method. The upconversion luminescence (UCL) intensity and red to green ratio of the multi-functional NaErF4 nanorods can be improved by Yb3+ doping. More importantly, owing to the decreased distance of Er and Yb, the significant enhancement of red UCL can be obtained, which is different to the usual green UCL of Yb/Er doped NaYF4 host. In addition, the intensity of UCL is strongest when the Yb3+-doped concentration reached 30%. The in vitro cell imaging and localized UCL spectra taken from HeLa cells revealed that these NaErF4: 30% Yb3+ nanorods are ideal nanoprobes with absence of autofluorescence for optical bioimaging. Moreover, these nanorods possess large X-ray absorption ions (Er3+ and doped Yb3+), and were successfully used as contrast agents for in vivo X-ray bioimaging for the first time. In addition to the excellent UCL and X-ray absorption properties, these nanorods present significant paramagnetic properties and can be used as T2-weighted magnetic resonance imaging (MRI) agents. Therefore, these enhanced red UCL NaErF4 nanocrystals with excellent paramagnetic properties and X-ray absorption properties can be used as promising multi-modal nanoprobes for optical bioimaging, MRI, computed X-ray tomography (CT), and may have potential applications in bioseparation.
Co-reporter:Ling Rao, Wei Lu, Tianmei Zeng, Zhigao Yi, Haibo Wang, Hongrong Liu and Songjun Zeng
Journal of Materials Chemistry A 2014 vol. 2(Issue 38) pp:6527-6533
Publication Date(Web):25 Jul 2014
DOI:10.1039/C4TB00675E
Small-sized BaLaF5:Mn/Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized for dual-modal X-ray and upconversion (UC) luminescence bioimaging by a simple solvothermal method. The size, shape, and UC luminescence intensity of the as-prepared UCNPs can be readily modified by changing the contents of Mn2+. The size of BaLaF5 UCNPs doped with Mn2+ decreased largely compared with Mn-free UCNPs. When increasing the content of Mn2+ from 5% to 20%, the size of UCNPs was gradually increased from 6.5 nm to 9.7 nm. The as-prepared BaLaF5 UCNPs doped with 20% Mn2+ present intense UC luminescence. The in vitro UC luminescence imaging of HeLa cells and localized spectra detected from HeLa cells and the background based on these BaLaF5:Mn/Yb/Er (20/20/2%) UCNPs indicate that this sample can serve as an ideal bioprobe with the absence of autofluorescence under the excitation of 980 nm laser. Moreover, an obvious UC signal was observed in in vivo UC bioimaging, demonstrating that these BaLaF5:Mn/Yb/Er (20/20/2%) UCNPs can also be used as bioprobes for whole body optical bioimaging. In addition, owing to the high X-ray mass absorption coefficients of Ba2+, La3+ and the doped Yb3+, the simultaneous X-ray and UC in vivo bioimaging of a nude mouse further demonstrate that the as-prepared UCNPs can be successfully used as dual-modal bioprobes. Ex vivo UC bioimaging revealed that these UCNPs gathered at the lung of a mouse at the initial time, demonstrating that this sample was suitable for the detection of the lung diseases. In addition, the cytotoxicity test showed that the UCNPs possessed little toxicity. Therefore, the small-sized BaLaF5:Yb/Er/Mn UCNPs are ideal nanoprobes for dual-modal UC luminescence/X-ray bioimaging with non-autofluorescence, and enhanced detection of the lung diseases.
Co-reporter:Zhigao Yi, Songjun Zeng, Wei Lu, Haibo Wang, Ling Rao, Hongrong Liu, and Jianhua Hao
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 6) pp:3839
Publication Date(Web):March 5, 2014
DOI:10.1021/am500383m
In this work, the amine-functionalized NaYbF4:Er nanoparticles were developed as dual-modal nanoprobes for synergistic upconversion (UC) luminescence and X-ray imaging in a single system by a simple one-step method of simultaneous synthesis and surface modification. The water-soluble NaYbF4:Er nanoparticles present excellent green and dominant red UC emissions. The in vitro cell imaging shows that the high-contrast green and intense red UC emissions can be observed from HeLa cells treated with these nanoparticles, indicating the successful labeling of HeLa cells. Moreover, the localized spectra measured from HeLa cells and background presented significant green and dominant red UC emissions with the absence of any autofluorescence, further verifying that these nanoparticles can be successfully used as ideal probes for optical UC bioimaging with high contrast and non-autofluorescence. In addition, the amine-functionalized NaYbF4:Er nanoparticles maintained low cell toxicity in HeLa cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. More importantly, these amine-functionalized NaYbF4:Er nanoparticles can also be used as X-ray imaging, owing to the large X-ray absorption efficiency of the Yb ion. The synergistic in vivo UC and X-ray imaging present significant UC luminescence and X-ray signals in the same region of a nude mouse, and the two signals are matched very well, which provides direct evidence for simultaneous UC luminescence and X-ray imaging in a single compound of lanthanide-doped material. Moreover, ex vivo UC imaging shows that these nanoparticles are first accumulated in the lung and gradually translocated from the lung into the liver. These results demonstrate that the amine-functionalized NaYbF4:Er nanoparticles presented here are very attractive nanoprobes for dual-modal UC luminescence and X-ray imaging with low cytotoxicity, autofluorescence free, and synergistic combination of the advantages of the two imaging modalities.Keywords: synergistic dual-modality bioimaging; upconversion luminescence bioimaging; upconversion nanoparticle; X-ray imaging;
Co-reporter:Zhigao Yi, Wei Lu, Chao Qian, Tianmei Zeng, Lingzhen Yin, Haibo Wang, Ling Rao, Hongrong Liu and Songjun Zeng
Biomaterials Science 2014 vol. 2(Issue 10) pp:1404-1411
Publication Date(Web):30 Jun 2014
DOI:10.1039/C4BM00158C
In this paper, we report a self-sacrificing route for fabrication of the Ce/Tb co-doped GdPO4 hollow spheres under hydrothermal conditions using the Gd(OH)CO3:Ce/Tb precursor as a template and NH4H2PO4 as a phosphorus source. The X-ray diffraction (XRD) patterns show the amorphous crystal nature of the precursor and pure hexagonal phase of the hollow spheres. The microstructures of the as-prepared precursor and hollow spheres were characterized by transmission electron microscopy (TEM) and scanning TEM (STEM) assays. The results reveal the urchin-like morphology of the solid precursor and hollow spheres. Bright green emissions of the spheres have been detected using an ultraviolet (UV) lamp at 288 nm and the calculated CIE coordinates are (0.289, 0.491). The energy transfer mechanism of Ce and Tb ions in the GdPO4 host has been investigated. The quantum efficiency of the hollow spheres was measured to be 61% and the lifetime calculated as 6.94 ms. In addition, the magnetic mass susceptibilities and magnetization of the spheres are found to be 6.39 × 10−5 emu gOe−1 and 1.27 emu g−1 at 20 kOe, respectively. Owing to their excellent downshift luminescence properties, the as-prepared GdPO4:Ce/Tb hollow spheres have been successfully applied in in vivo luminescence and X-ray bioimaging for the first time. Moreover, three-dimensional (3D) in vivo X-ray bioimaging of the mouse can provide the accurate location from multiple directions. The high contrast ratio makes the spheres a promising X-ray contrast agent. Due to the hollow structure, these GdPO4:Ce/Tb hollow spheres were also used as drug delivery systems for doxorubicin (DOX) loading and release. The drug loading efficiency was measured to be 17% at a pH value of 7.4, and the pH-dependent drug release was studied. 47% of the loaded DOX was released within 10 h when pH = 5, while there was only 30% during the same time at pH = 7.4 and it took nearly 48 h to reach a comparable level. The different release nature gives these spheres a promising application in targeted therapy of tumors.
Co-reporter:Ling Rao, Wei Lu, Tianmei Zeng, Zhigao Yi, Haibo Wang, Hongrong Liu and Songjun Zeng
Dalton Transactions 2014 vol. 43(Issue 35) pp:13343-13348
Publication Date(Web):15 Jul 2014
DOI:10.1039/C4DT01572J
Polyethylene glycol (PEG) modified BaLuF5:Gd/Yb/Er upconversion nanoparticles (UCNPs) were synthesized by a facile one-pot hydrothermal method for simultaneous synthesis and surface functionalization. The novel, excellently biocompatible and water-soluble bioprobes were used for simultaneous upconversion (UC) luminescence and X-ray bioimaging for the first time. The as-prepared BaLuF5:Gd/Yb/Er UCNPs possess a face-centered cubic structure with an average size of 23.7 ± 2.7 nm. Under 980 nm laser excitation, these UCNPs emitted intense UC luminescence via a two-photon process. In vitro bioimaging and localized luminescence spectra detected from HeLa cells and the background reveal that these UCNPs are ideal candidates for optical bioimaging in the absence of autofluorescence. Furthermore, the synergistic in vivo UC luminescence and X-ray bioimaging reveal that these PEG-modified BaLuF5:Gd/Yb/Er UCNPs can be successfully used as ideal dual-modal bioprobes. These results demonstrate that these PEG modified UCNPs are ideal multi-modal nanoprobes for bioimaging.
Co-reporter:Zhigao Yi, Wei Lu, Tianmei Zeng, Chao Qian, Haibo Wang, Ling Rao, Hongrong Liu and Songjun Zeng
RSC Advances 2014 vol. 4(Issue 91) pp:49916-49923
Publication Date(Web):11 Sep 2014
DOI:10.1039/C4RA08087D
Herein, a series of hexagonal phase lanthanide (Ln3+, Ln3+ = Eu3+, Dy3+, Tb3+) doped NaCeF4 nanorods (NRs) with uniform morphology and monodispersity have been successfully synthesized via a typical hydrothermal method using oleic acid as the capping agent. The crystal phase and microstructure of the obtained NRs were analyzed by X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM). The down conversion (DC) luminescence properties and mechanisms of the as-prepared NaCeF4:Ln3+ NRs have been discussed in detail. The as-prepared samples show the characteristic f–f transition of Ln3+ (Ln3+ = Eu3+, Dy3+, Tb3+). The decay time and quantum yield of these obtained NRs are also studied. Moreover, tunable multicolor, especially white emissions, can be successfully achieved via varying the doping ions and doping concentration. By increasing the content of Eu3+, the emission colors vary from light green to white and finally to light red under the excitation of 395 nm. The calculated CIE coordinates of the obtained white emissions are (0.33, 0.31), which are very close to the standard white light located at (0.33, 0.33). This is the first time to demonstrate that white light emission is achieved via only singly-doping Eu3+ into the NaCeF4 system. In addition, the multicolor output changes from yellowish-green to yellow under the excitation at 261 nm, which was also obtained by only tuning the doped content of Dy3+ in the NaCeF4 host. As for Tb3+, bright yellowish green emissions were obtained under excitation at 261 nm. Moreover, the cathodoluminescence (CL) spectra demonstrate that these NRs can emerge as ideal nanophosphors under electron beam excitation. Therefore, the as-prepared NaCeF4:Ln3+ NRs with tunable multicolor output and bright white emissions might be applied in field-emission devices, multicolor displays and solid state lasers.
Co-reporter:Zhigao Yi, Guozhong Ren, Ling Rao, Haibo Wang, Hongrong Liu, Songjun Zeng
Journal of Alloys and Compounds 2014 Volume 589() pp:502-506
Publication Date(Web):15 March 2014
DOI:10.1016/j.jallcom.2013.12.036
•Hexagonal phase prism-like NaYbF4 microtubes were synthesized by a hydrothermal method.•Tunable multicolor can be obtained by simply tuning Tm3+ and Ho3+ concentration in NaYbF4 system.•Tunable multicolor emissions can be achieved via increasing excitation pumping power.•Excellent paramagnetic property of NaYbF4 has been studied for the first time.In this paper, the lanthanide (Ln) doped fluorescent/magnetic NaYbF4 microtubes with hexagonal phase were synthesized via a hydrothermal method using oleic acid as a capping ligand and surface modifier. The as-prepared samples were characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), upconversion luminescence (UCL) spectra, and vibrating sample magnetometer (VSM). The TEM and FE-SEM observations revealed that the NaYbF4 microtubes present high quality hexagonal prism shape. Under the excitation of a 980 nm laser diode (LD) with a power density of 0.5 W cm−2, the UCL colors can be tuned from purplish blue to blue, greenish white, and further to yellowish green by adjusting the Tm3+ and Ho3+ content in NaYbF4 system. Moreover, the brighter greenish white light can be readily achieved via increasing excitation power. The UCL mechanisms for the white emission were proposed based on the spectral and pumping power dependence analyses. Moreover, these as-prepared NaYbF4 microtubes exhibit excellent paramagnetic property at room temperature. The magnetic mass susceptibility and magnetization are measured to 4.17 × 10−5 emu/gOe and ∼0.84 emu g−1 at 20 kOe, respectively. Therefore, these NaYbF4 microtubes with hexagonal prism shape, tunable multicolor UCL and excellent paramagnetic property imply that NaYbF4 is an excellent host material and may find applications in flat-panel displays, lasers photonics and dual-modal bioprobes.
Co-reporter:Zhigao Yi, Wei Lu, Yaru Xu, Jing Yang, Li Deng, Chao Qian, Tianmei Zeng, Haibo Wang, Ling Rao, Hongrong Liu, Songjun Zeng
Biomaterials 2014 35(36) pp: 9689-9697
Publication Date(Web):
DOI:10.1016/j.biomaterials.2014.08.021
Co-reporter:Songjun Zeng, Haibo Wang, Wei Lu, Zhigao Yi, Ling Rao, Hongrong Liu, Jianhua Hao
Biomaterials 2014 35(9) pp: 2934-2941
Publication Date(Web):
DOI:10.1016/j.biomaterials.2013.11.082
Co-reporter:Haibo Wang, Zhigao Yi, Ling Rao, Hongrong Liu and Songjun Zeng
Journal of Materials Chemistry A 2013 vol. 1(Issue 35) pp:5520-5526
Publication Date(Web):02 Jul 2013
DOI:10.1039/C3TC30796D
In this paper, optical/magnetic multi-functional NaErF4 nanocrystals with high quality, different phases and shapes were synthesized by a simple hydrothermal method using oleic acid as the capping agent. The structure, upconversion luminescence and magnetic properties were characterized by various techniques. The transmission electron microscopy results reveal that the nanocrystals are of high quality and can be self-assembled into a two-dimensional ordered structure. Moreover, the crystal phase and shape can be readily controlled by adjusting the reaction temperature and F− content. The results reveal that high temperature can favor the formation of a hexagonal phase structure and promote the phase transformation from the cubic to hexagonal phase. The phase transformation mechanism based on the free energy theory was discussed in detail. In addition, the F− content plays a critical role in determining the morphology of the final products. A high F− content is beneficial for the formation of the one-dimensional rod-like shape. Interestingly, phase-induced upconversion luminescence color tuning from red to green was observed. All of the as-prepared NaErF4 nanocrystals possess paramagnetic properties at room temperature and the magnetizations of the nanocrystals with spherical-like cubic, cubic, and rod-like shapes were measured as 1.69 emu g−1, 2.53 emu g−1and 2.29 emu g−1 at 20 kOe, respectively, which are larger than most previously reported Gd-based nanocrystals. In addition, T2-weighted magnetic resonance imaging based on these NaErF4 nanocrystals was demonstrated for the first time. Therefore, these tunable upconversion fluorescent NaErF4 nanocrystals with excellent paramagnetic properties can be used as promising dual-modal nanoprobes for optical bioimaging and magnetic resonance imaging, and may have potential applications in bioseparation.
Co-reporter:Zhenluan Xue, Zhigao Yi, Xiaolong Li, Youbin Li, Mingyang Jiang, Hongrong Liu, Songjun Zeng
Biomaterials (January 2017) Volume 115() pp:90-103
Publication Date(Web):January 2017
DOI:10.1016/j.biomaterials.2016.11.024
In this work, we demonstrated multifunctional NaYbF4: Tm3+/Gd3+ upconversion (UC) nanorods (UCNRs) with near-infrared (NIR)-to-NIR emission and controlled phase and size for UC optical and T1/T2 dual-weighted magnetic resonance (MR) imaging-guided small tumor detection and tri-modal bioimaging. Cell toxicity and post-injection histology results revealed that our designed UCNRs present low biotoxicity and good biocompatibility in living animals. Real-time tracking based on UCNRs in living mice demonstrated that the UCNRs were mainly accumulated in the reticuloendothelial system (RES) and excreted through the hepatic pathway. Additionally, the UCNRs exhibited high X-ray absorption coefficient and large K-edge value, resulting in efficient in vivo CT imaging. A new type of binary (Yb3+/Gd3+) MR contrast agent for simultaneous T1/T2 dual-weighted MR imaging was achieved by doping Gd3+ into NaYbF4 host. Importantly, a small tumor (5 mm in diameter) could be detected in vivo by intravenously injecting UCNRs under UC optical and MR imaging modalities. Therefore, these multifunctional nanoprobes based on NaYbF4:Tm3+/Gd3+ UCNRs with remarkable NIR-to-NIR emission provide potential applications for tri-modal UC optical, CT, binary T1/T2 MR imaging, and early-stage tumor detection in nanomedicine.
Co-reporter:Zhenluan Xue, Zhigao Yi, Xiaolong Li, Youbin Li, Mingyang Jiang, Hongrong Liu, Songjun Zeng
Biomaterials (January 2017) Volume 115() pp:90-103
Publication Date(Web):January 2017
DOI:10.1016/j.biomaterials.2016.11.024
Co-reporter:Xiaolong Li, Zhigao Yi, Zhenluan Xue, Songjun Zeng, Hongrong Liu
Materials Science and Engineering: C (1 June 2017) Volume 75() pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.msec.2017.02.085
•The multifunctional UCNPs with high monodispersity were synthesized.•The UCNPs present large r1 value and binary CT contrast agents.•These UCNPs were demonstrated as optimal probes for tri-modal bioimaging.Development of high-quality upconversion nanoparticles (UCNPs) with combination of the merits of multiple molecular imaging techniques, such as, upconversion luminescence (UCL) imaging, X-ray computed tomography (CT), and magnetic resonance (MR) imaging, could significantly improve the accuracy of biological diagnosis. In this work, multifunctional BaYbF5: Gd/Er (50:2 mol%) UCNPs were synthesized via a solvothermal method using oleic acid (OA) as surface ligands (denoted as OA-UCNPs). The OA-UCNPs were further treated by diluted HCl to form ligand-free UCNPs (LF-UCNPs) for later bioimaging applications. The cytotoxicity assay in HeLa cells shows low cell toxicity of these LF-UCNPs. Owing to the efficient UCL of BaYbF5: Gd/Er, the LF-UCNPs were successfully used as luminescent bioprobe in UCL bioimaging. And, X-ray CT imaging reveals that BaYbF5: Gd/Er UCNPs can act as potential contrast agents for detection of the liver and spleen in the live mice owing to the high-Z elements (e.g., Ba, Yb, and Gd) in host matrix. Moreover, with the addition of Gd, the as-designed UCNPs exhibit additional positive contrast enhancement in T1-weighted MR imaging. These findings demonstrate that BaYbF5: Gd/Er UCNPs are potential candidates for tri-modal imaging.Multifunctional BaYbF5: Gd/Er upconversion nanoparticles with efficient upconversion emission, high absorption coefficient, predominant paramagnetic behavior, and low biological toxicity were demonstrated for tri-modality in vivo UCL, CT and MR imaging.
Co-reporter:Haibo Wang, Zhigao Yi, Ling Rao, Hongrong Liu and Songjun Zeng
Journal of Materials Chemistry A 2013 - vol. 1(Issue 35) pp:NaN5526-5526
Publication Date(Web):2013/07/02
DOI:10.1039/C3TC30796D
In this paper, optical/magnetic multi-functional NaErF4 nanocrystals with high quality, different phases and shapes were synthesized by a simple hydrothermal method using oleic acid as the capping agent. The structure, upconversion luminescence and magnetic properties were characterized by various techniques. The transmission electron microscopy results reveal that the nanocrystals are of high quality and can be self-assembled into a two-dimensional ordered structure. Moreover, the crystal phase and shape can be readily controlled by adjusting the reaction temperature and F− content. The results reveal that high temperature can favor the formation of a hexagonal phase structure and promote the phase transformation from the cubic to hexagonal phase. The phase transformation mechanism based on the free energy theory was discussed in detail. In addition, the F− content plays a critical role in determining the morphology of the final products. A high F− content is beneficial for the formation of the one-dimensional rod-like shape. Interestingly, phase-induced upconversion luminescence color tuning from red to green was observed. All of the as-prepared NaErF4 nanocrystals possess paramagnetic properties at room temperature and the magnetizations of the nanocrystals with spherical-like cubic, cubic, and rod-like shapes were measured as 1.69 emu g−1, 2.53 emu g−1and 2.29 emu g−1 at 20 kOe, respectively, which are larger than most previously reported Gd-based nanocrystals. In addition, T2-weighted magnetic resonance imaging based on these NaErF4 nanocrystals was demonstrated for the first time. Therefore, these tunable upconversion fluorescent NaErF4 nanocrystals with excellent paramagnetic properties can be used as promising dual-modal nanoprobes for optical bioimaging and magnetic resonance imaging, and may have potential applications in bioseparation.
Co-reporter:Ling Rao, Wei Lu, Tianmei Zeng, Zhigao Yi, Haibo Wang, Hongrong Liu and Songjun Zeng
Journal of Materials Chemistry A 2014 - vol. 2(Issue 38) pp:NaN6533-6533
Publication Date(Web):2014/07/25
DOI:10.1039/C4TB00675E
Small-sized BaLaF5:Mn/Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized for dual-modal X-ray and upconversion (UC) luminescence bioimaging by a simple solvothermal method. The size, shape, and UC luminescence intensity of the as-prepared UCNPs can be readily modified by changing the contents of Mn2+. The size of BaLaF5 UCNPs doped with Mn2+ decreased largely compared with Mn-free UCNPs. When increasing the content of Mn2+ from 5% to 20%, the size of UCNPs was gradually increased from 6.5 nm to 9.7 nm. The as-prepared BaLaF5 UCNPs doped with 20% Mn2+ present intense UC luminescence. The in vitro UC luminescence imaging of HeLa cells and localized spectra detected from HeLa cells and the background based on these BaLaF5:Mn/Yb/Er (20/20/2%) UCNPs indicate that this sample can serve as an ideal bioprobe with the absence of autofluorescence under the excitation of 980 nm laser. Moreover, an obvious UC signal was observed in in vivo UC bioimaging, demonstrating that these BaLaF5:Mn/Yb/Er (20/20/2%) UCNPs can also be used as bioprobes for whole body optical bioimaging. In addition, owing to the high X-ray mass absorption coefficients of Ba2+, La3+ and the doped Yb3+, the simultaneous X-ray and UC in vivo bioimaging of a nude mouse further demonstrate that the as-prepared UCNPs can be successfully used as dual-modal bioprobes. Ex vivo UC bioimaging revealed that these UCNPs gathered at the lung of a mouse at the initial time, demonstrating that this sample was suitable for the detection of the lung diseases. In addition, the cytotoxicity test showed that the UCNPs possessed little toxicity. Therefore, the small-sized BaLaF5:Yb/Er/Mn UCNPs are ideal nanoprobes for dual-modal UC luminescence/X-ray bioimaging with non-autofluorescence, and enhanced detection of the lung diseases.
Co-reporter:Zhigao Yi, Xiaolong Li, Wei Lu, Hongrong Liu, Songjun Zeng and Jianhua Hao
Journal of Materials Chemistry A 2016 - vol. 4(Issue 15) pp:NaN2722-2722
Publication Date(Web):2016/03/22
DOI:10.1039/C5TB02375K
Lanthanide nanoparticles (NPs), which are known as upconversion fluorescence probes for multimodal bioimaging, including magnetic resonance imaging (MRI), have attracted much attentions. In MRI, conventional contrast agents are generally employed separately in a single type of MRI. T1- and T2-weighted MRI alone have unique limitations; therefore, it is urgently necessary to combine the two modalities so as to be able to provide more comprehensive and synergistic diagnostic information than the single modality of MRI. Unfortunately, there is a lack of advanced materials as enhancing agents which are fully suitable for bimodal MRI. Here, we report a new class of hybrid lanthanide nanoparticles as synergistic contrast agents in T1/T2 dual-weighted MRI and imaging-directed tumor diagnosis. The r2/r1 value of BaGdF5 NPs can be readily adjusted from 2.8 to 334.8 by doping with 0%, 50%, or 100% Ln3+ (Ln3+ = Yb3+, Er3+, or Dy3+), respectively. Among these, BaGdF5:50% Er3+ NPs were successfully used as binary contrast agents for T1/T2 dual-weighted MRI and synergistic tumor diagnosis in vivo. These findings reveal that the longitudinal and transverse relaxivities of these Gd3+-based NPs can be controlled by tuning the Ln3+ dopants and their concentrations, providing a simple and general method for designing simultaneous T1/T2 enhancing agents.
Co-reporter:Ling Rao, Wei Lu, Tianmei Zeng, Zhigao Yi, Haibo Wang, Hongrong Liu and Songjun Zeng
Dalton Transactions 2014 - vol. 43(Issue 35) pp:NaN13348-13348
Publication Date(Web):2014/07/15
DOI:10.1039/C4DT01572J
Polyethylene glycol (PEG) modified BaLuF5:Gd/Yb/Er upconversion nanoparticles (UCNPs) were synthesized by a facile one-pot hydrothermal method for simultaneous synthesis and surface functionalization. The novel, excellently biocompatible and water-soluble bioprobes were used for simultaneous upconversion (UC) luminescence and X-ray bioimaging for the first time. The as-prepared BaLuF5:Gd/Yb/Er UCNPs possess a face-centered cubic structure with an average size of 23.7 ± 2.7 nm. Under 980 nm laser excitation, these UCNPs emitted intense UC luminescence via a two-photon process. In vitro bioimaging and localized luminescence spectra detected from HeLa cells and the background reveal that these UCNPs are ideal candidates for optical bioimaging in the absence of autofluorescence. Furthermore, the synergistic in vivo UC luminescence and X-ray bioimaging reveal that these PEG-modified BaLuF5:Gd/Yb/Er UCNPs can be successfully used as ideal dual-modal bioprobes. These results demonstrate that these PEG modified UCNPs are ideal multi-modal nanoprobes for bioimaging.
Co-reporter:Zhigao Yi, Wei Lu, Chao Qian, Tianmei Zeng, Lingzhen Yin, Haibo Wang, Ling Rao, Hongrong Liu and Songjun Zeng
Biomaterials Science (2013-Present) 2014 - vol. 2(Issue 10) pp:NaN1411-1411
Publication Date(Web):2014/06/30
DOI:10.1039/C4BM00158C
In this paper, we report a self-sacrificing route for fabrication of the Ce/Tb co-doped GdPO4 hollow spheres under hydrothermal conditions using the Gd(OH)CO3:Ce/Tb precursor as a template and NH4H2PO4 as a phosphorus source. The X-ray diffraction (XRD) patterns show the amorphous crystal nature of the precursor and pure hexagonal phase of the hollow spheres. The microstructures of the as-prepared precursor and hollow spheres were characterized by transmission electron microscopy (TEM) and scanning TEM (STEM) assays. The results reveal the urchin-like morphology of the solid precursor and hollow spheres. Bright green emissions of the spheres have been detected using an ultraviolet (UV) lamp at 288 nm and the calculated CIE coordinates are (0.289, 0.491). The energy transfer mechanism of Ce and Tb ions in the GdPO4 host has been investigated. The quantum efficiency of the hollow spheres was measured to be 61% and the lifetime calculated as 6.94 ms. In addition, the magnetic mass susceptibilities and magnetization of the spheres are found to be 6.39 × 10−5 emu gOe−1 and 1.27 emu g−1 at 20 kOe, respectively. Owing to their excellent downshift luminescence properties, the as-prepared GdPO4:Ce/Tb hollow spheres have been successfully applied in in vivo luminescence and X-ray bioimaging for the first time. Moreover, three-dimensional (3D) in vivo X-ray bioimaging of the mouse can provide the accurate location from multiple directions. The high contrast ratio makes the spheres a promising X-ray contrast agent. Due to the hollow structure, these GdPO4:Ce/Tb hollow spheres were also used as drug delivery systems for doxorubicin (DOX) loading and release. The drug loading efficiency was measured to be 17% at a pH value of 7.4, and the pH-dependent drug release was studied. 47% of the loaded DOX was released within 10 h when pH = 5, while there was only 30% during the same time at pH = 7.4 and it took nearly 48 h to reach a comparable level. The different release nature gives these spheres a promising application in targeted therapy of tumors.
