Liangjun Zhou

Mn2+ Dopant-Controlled Synthesis of NaYF4:Yb/Er Upconversion Nanoparticles for in vivo Imaging and Drug Delivery

Pure dark red emission (650-670 nm) of NaYF(4):Yb/Er upconversion nanoparticles (UCNPs) is achieved by manganese ions (Mn(2+)) doping. In addition, the Mn(2+)-doping can also control the crystalline phase and size of the resulting UCNPs simultaneously. Drug delivery studies suggest the promise of these UCNPs as drug carriers for intracellular drug delivery and eventually as a multifunctional nanoplatform for simultaneous diagnosis and therapy.

High-Throughput Synthesis of Single-Layer MoS2 Nanosheets as a Near-Infrared Photothermal-Triggered Drug Delivery for Effective Cancer Therapy

We report here a simple, high-yield yet low-cost approach to design single-layer MoS2 nanosheets with controllable size via an improved oleum treatment exfoliation process. By decorating MoS2 nanosheets with chitosan, these functionalized MoS2 nanosheets have been developed as a chemotherapeutic drug nanocarrier for near-infrared (NIR) photothermal-triggered drug delivery, facilitating the combination of chemotherapy and photothermal therapy into one system for cancer therapy. Loaded doxorubicin could be controllably released upon the photothermal effect induced by 808 nm NIR laser irradiation. In vitro and in vivo tumor ablation studies demonstrate a better synergistic therapeutic effect of the combined treatment, compared with either chemotherapy or photothermal therapy alone. Finally, MoS2 nanosheets can also be used as a promising contrast agent in X-ray computed tomography imaging due to the obvious X-ray absorption ability of Mo. As a result, the high-throughput oleum treatment exfoliation process could be extended for fabricating other 2D nanomaterials, and the NIR-triggered drug release strategy was encouraging for simultaneous imaging-guided cancer theranostic application.

Red‐Emitting Upconverting Nanoparticles for Photodynamic Therapy in Cancer Cells Under Near‐Infrared Excitation

Upconverting nanoparticles (UCNPs) have attracted considerable attention as potential photosensitizer carriers for photodynamic therapy (PDT) in deep tissues. In this work, a new and efficient NIR photosensitizing nanoplatform for PDT based on red-emitting UCNPs is designed. The red emission band matches well with the efficient absorption bands of the widely used commercially available photosensitizers (Ps), benefiting the fluorescence resonance energy transfer (FRET) from UCNPs to the attached photosensitizers and thus efficiently activating them to generate cytotoxic singlet oxygen. Three commonly used photosensitizers, including chlorine e6 (Ce6), zinc phthalocyanine (ZnPc) and methylene blue (MB), are loaded onto the alpha-cyclodextrin-modified UCNPs to form Ps@UCNPs complexes that efficiently produce singlet oxygen to kill cancer cells under 980 nm near-infrared excitation. Moreover, two different kinds of drugs are co-loaded onto these nanoparticles: chemotherapy drug doxorubicin and PDT agent Ce6. The combinational therapy based on doxorubicin (DOX)-induced chemotherapy and Ce6-triggered PDT exhibits higher therapeutic efficacy relative to the individual means for cancer therapy in vitro.

Enhanced Red Emission from GdF3:Yb3+,Er3+ Upconversion Nanocrystals by Li+ Doping and Their Application for Bioimaging

Under 980 nm near-infrared (NIR) excitation, upconversion luminescent (UCL) emission of GdF(3):Yb,Er upconversion nanoparticles (UCNPs) synthesized by a simple and green hydrothermal process can be tuned from yellow to red by varying the concentration of dopant Li(+) ions. A possible mechanism for enhanced red upconverted radiation is proposed. A layer of silica was coated onto the surface of GdF(3):Yb,Er,Li UCNPs to improve their biocompatibility. The silica-coated GdF(3):Yb,Er,Li UCNPs show great advantages in cell labeling and in vivo optical imaging. Moreover, GdF(3) UCNPs also exhibited a positive contrast effect in T(1)-weighted magnetic resonance imaging (MRI). These results suggest that the GdF(3) UCNPs could act as dual-modality biolabels for optical imaging and MRI.

Lanthanide ion-doped GdPO4 nanorods with dual-modal bio-optical and magnetic resonance imaging properties

Here, dual-modal bioprobes for combined optical and magnetic resonance (MR) imaging are reported. Gadolinium orthophosphate (GdPO(4)) nanorods co-doped with light-emitting lanthanide ions have been successfully prepared through a hydrothermal method. An efficient downconversion luminescence from Ce/Tb or Eu doped GdPO(4) nanorods and upconversion luminescence from Yb/Er co-doped GdPO(4) nanorods are observed, respectively, which offers the optical modality for the nanoprobes. Notably, we first report the upconversion phenomenon based on the GdPO(4) matrix under 980 nm near infrared irradiation. The possibility of using these nanoprobes with downconversion and upconversion luminescent emissions for optical cell imaging is also demonstrated. Furthermore, these Gd(3+)-containing nanophosphors show good positive signal-enhancement ability when performed under a 4.7 T MR imaging scanner, indicating they have potential as T(1) MR imaging contrast agents. Thus, nanoprobes based on GdPO(4) nanophosphors are shown to provide the dual modality of optical and MR imaging.

A magnetic graphene hybrid functionalized with beta-cyclodextrins for fast and efficient removal of organic dyes

A β-cyclodextrin (β-CD) functionalized magnetic graphene hybrid (mGO-β-CD) has been prepared and its application as an adsorbent for the removal of organic dyes has been investigated. Magnetic graphene hybrids (mGOs) were first synthesized via a chemical precipitation method, and then β-CDs were applied to further functionalize the resultant mGO hybrid. The results demonstrate that the as-prepared mGO-β-CD hybrid exhibits greatly enhanced adsorption performance in water. Acid fuchsin and Rhodamine 6G, the typical dye pollutants, can be effectively removed from their solutions by the mGO-β-CD hybrid. The maximum adsorption capability of the mGO-β-CD hybrid is several times, even hundreds of times higher than that of the reported carbonaceous materials. Moreover, ca. 90% of the dye removal efficiency can be retained after six adsorption–desorption cycles. In addition, the mGO-β-CD hybrid exhibits negligible toxicity toward the normal cells. Conclusively, the resultant mGO-β-CD hybrid proves to be a magnetically separable, efficient and non-toxic adsorbent for dye removal.

A new near infrared photosensitizing nanoplatform containing blue-emitting up-conversion nanoparticles and hypocrellin A for photodynamic therapy of cancer cells

The utilization of up-conversion nanoparticles (UCNPs) for photodynamic therapy (PDT) has gained significant interest due to their unique ability to convert near infrared light to UV/visible light. Previous work mainly focused on the fabrication of green and red emitting UCNPs to load photosensitizers (PSs) for PDT. In this work, we firstly developed a new multifunctional nanoplatform combining blue-emitting UCNPs with blue-light excited PS (hypocrellin A, HA) as a NIR photosensitizing nanoplatform for PDT of cancer cells. Tween 20 coated NaYbF4:Tm, Gd@NaGdF4 UCNPs (Tween 20-UCNPs) with strong blue up-conversion luminescence and good water dispersibility were prepared for use as PS carriers. The blue emission band matched well with the efficient absorption band of HA, thereby facilitating the resonance energy transfer from UCNPs to HA and then activating HA to produce singlet oxygen ((1)O2). The in vitro study showed that these Tween 20-UCNPs@HA complexes could efficiently produce (1)O2 to kill cancer cells under 980 nm NIR excitation. Moreover, these Gd(3+) and Yb(3+) containing nanoparticles also exhibited positive contrast effects in both T1 weighted magnetic resonance imaging (MRI) and computed tomography (CT) imaging, making them become a multifunctional platform for simultaneous PDT and bio-imaging.

Mesoporous NaYbF4@NaGdF4 core-shell up-conversion nanoparticles for targeted drug delivery and multimodal imaging

We developed a facile strategy to obtain a new kind of mesoporous core-shell structured up-conversion nanoparticles (mUCNPs), composed of a NaYbF4:2%Er core and a mesoporous NaGdF4 shell. This mesoporous shell not only enhanced the up-conversion luminescence but also endowed many other functionalities of the nanoparticles such as drug delivery and bio-imaging capabilities. Moreover, after being conjugated with polyethylenimine (PEI) and folic acid (FA), core-shell mUCNPs exhibited good water dispersibility, enhanced drug delivery efficiency, and remarkable targeting ability to cancer cells. To certify the folate receptors (FR)-mediated targeted drug delivery, cell viability assay, cell up-conversion luminescence imaging and flow cytometry analysis were carried out. Furthermore, apart from the application for targeted drug delivery, the as-prepared core-shell mUCNPs could also be employed as the contrast agents for X-ray computed tomography (CT) and magnetic resonance (MR) imaging, because of the strong X-ray attenuation ability of Yb and high longitudinal molar relaxivity (r1) of Gd in the nanoparticles, providing the potential for simultaneously bio-imaging and cancer-targeting therapy.

Multifunctional Rbx WO3 nanorods for simultaneous combined chemo-photothermal therapy and photoacoustic/CT imaging.

Light-triggered drug delivery based on near-infrared (NIR)-mediated photothermal nanocarriers has received tremendous attention for the construction of cooperative therapeutic systems in nanomedicine. Herein, a new paradigm of light-responsive drug carrier that doubles as a photothermal agent is reported based on the NIR light-absorber, Rb(x) WO3 (rubidium tungsten bronze, Rb-TB) nanorods. With doxorubicin (DOX) payload, the DOX-loaded Rb-TB composite (Rb-TB-DOX) simultaneously provides a burst-like drug release and intense heating effect upon 808-nm NIR light exposure. MTT assays show the photothermally enhanced antitumor activity of Rb-TB-DOX to the MCF-7 cancer cells. Most remarkably, Rb-TB-DOX combined with NIR irradiation also shows dramatically enhanced chemotherapeutic effect to DOX-resistant MCF-7 cells compared with free DOX, demonstrating the enhanced efficacy of combinational chemo-photothermal therapy for potentially overcoming drug resistance in cancer chemotherapy. Furthermore, in vivo study of combined chemo-photothermal therapy is also conducted and realized on pancreatic (Pance-1) tumor-bearing nude mice. Apart from its promise for cancer therapy, the as-prepared Rb-TB can also be employed as a new dual-modal contrast agent for photoacoustic tomography and (PAT) X-ray computed tomography (CT) imaging because of its high NIR optical absorption capability and strong X-ray attenuation ability, respectively. The results presented in the current study suggest promise of the multifunctional Rb(x)WO3 nanorods for applications in cancer theranostics.

Design of multifunctional alkali ion doped CaF2 upconversion nanoparticles for simultaneous bioimaging and therapy

Herein, alkali ion doped CaF2 upconversion nanoparticles (UCNPs) were first reported as a multifunctional theranostic platform for dual-modal imaging and chemotherapy. Interestingly, we found that the alkali ions doping approach could efficiently enhance the upconversion luminescence (UCL) intensity, whereas slightly affect the phase and morphology of the resulting products. In order to further improve the UCL efficacy for bioimaging, a pristine CaF2 shell was grown on the CaF2:Yb, Er core surface to enhance the UCL intensity. After being transferred into hydrophilic UCNPs, these water-soluble UCNPs could be served as contrast agents for in vitro/in vivo UCL imaging and X-ray computed tomography (CT) imaging. Furthermore, the as-prepared UCNPs could also be employed as nano-carriers for drug delivery. Doxorubicin (DOX) can be easily loaded onto the UCNPs and the DOX-loaded UCNPs exhibit a good cell killing ability. Therefore, the multifunctional core-shell CaF2 UCNPs with UCL/CT imaging and drug carrier properties may find extensive applications in simultaneous imaging diagnosis and therapy.