Bio

Bio

Work Experience:

Post-Doctoral Scholar. Department of Radiology, Stanford. (04/2019-present)
Research Associate. Department of Radiology, University of Wisconsin-Madison. (04/2018-04/2019)
Research Assistant. Australian Institute for Bioengineering and Nanotechnology, The University of Queensland. (11/2017-01/2018)
Visiting Researcher. Department of Chemical and Biomolecular Engineering, The National University of Singapore. (10/2016-12/2016)

Honors & Awards

  • Graduate School International Travel Award. (GSITA), The University of Queensland (2016)
  • AIBN Science Image Contest, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland (2016)
  • UQI and UQ-AIBN Scholarship, The University of Queensland (2013-2017)

Boards, Advisory Committees, Professional Organizations

  • Member, World Molecular Imaging Society (2019 - Present)
  • Member, Society of Nuclear Medicine and Molecular Imaging (2019 - Present)
  • Member, Centre for Microscopy and Microanalysis, The University of Queensland (2014 - 2016)
  • Member, Australian Nanotechnology Network (2015 - Present)

Professional Education

  • Doctor of Philosophy, University Of Queensland (2018)
  • Master of Science, Xiamen University (2012)
  • Bachelor of Science, Xiamen University (2009)

Stanford Advisors

Contact

Publications

All Publications

  • H2 S-Scavenged and Activated Iron Oxide-Hydroxide Nanospindles for MRI-Guided Photothermal Therapy and Ferroptosis in Colon Cancer. Small (Weinheim an der Bergstrasse, Germany) Li, Y., Chen, W., Qi, Y., Wang, S., Li, L., Li, W., Xie, T., Zhu, H., Tang, Z., Zhou, M. 2020: e2001356

    Abstract

    Overproduced hydrogen sulfide (H2 S) is of vital importance for the progress of colon cancer and promotes cancer cellular proliferation. Devising pharmacological nanomaterials for tumor-specific H2 S activation will be significant for precise colon cancer treatment. Herein, a biocompatible fusiform iron oxide-hydroxide nanospindles (FeOOH NSs) nanosystem for magnetic resonance imaging (MRI), ferroptosis, and H2 S based cascade reaction-enhanced combinational colon cancer treatment is developed. The FeOOH NSs can effectively scavenge endogenous H2 S via the reduction reaction to prohibit the growth of CT26 colon cancer. The cascade produced FeS driven by overexpressed H2 S exhibits near-infrared-triggered photothermal therapy capability and Fe2+ -mediated ferroptosis functionality. Meanwhile, the as-prepared FeOOH NSs can light up tumor tissues as a potent MRI contrast agent. Additionally, FeOOH NSs present desirable biosafety in a murine model for up to three months and avoid any long-term toxicity. Furthermore, it is found that these H2 S-responsible nanotheranostics do not cause any cure effects on other cancer types, such as 4T1 breast cancer. Overall, the findings illustrate that the biocompatible FeOOH NSs can be successfully employed as a theranostic for specifically treating colon cancer, which may promote the clinical translation and development of H2 S-responsive nanoplatforms.

    View details for DOI 10.1002/smll.202001356

    View details for PubMedID 32789963

  • Light-Activatable Synergistic Therapy of Drug-Resistant Bacteria-Infected Cutaneous Chronic Wounds and Nonhealing Keratitis by Cupriferous Hollow Nanoshells. ACS nano Qiao, Y., He, J., Chen, W., Yu, Y., Li, W., Du, Z., Xie, T., Ye, Y., Hua, S. Y., Zhong, D., Yao, K., Zhou, M. 2020

    Abstract

    Due to the inability to spontaneously heal and vulnerability to bacterial infection, diabetic patients are frustrated by unexpected epithelium injuries in daily life. Notably, a drug-resistant bacterial infection may result in a long-term impact to the natural function of damaged organs. It is imperative to develop strategies that promote injury recovery and eradicate drug-resistant infection simultaneously. Here, we present a composite structured cupriferous hollow nanoshell (AuAgCu2O NS) that consists of a hollow gold-silver (AuAg) core and Cu2O shell as a photothermal therapeutic agent for a cutaneous chronic wound and nonhealing keratitis with drug-resistant bacterial infection. The controllable photothermal therapeutic effect and released silver ion from the hollow AuAg core possess a synergistic effect to eradicate multi-drug-resistant bacteria, including extended-spectrum beta-lactamase Escherichia coli (ESBL E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). Meanwhile, the released copper ion from the Cu2O shell could expedite endothelial cell angiogenesis and fibroblast cell migration, thus boosting wound-healing effects. In both infection-complicated disease models, the ophthalmic clinical score, wound closure rates, and histopathology analysis demonstrate that the AuAgCu2O NSs could facilitate the re-epithelialization at the wound area and eliminate the complicated bacterial infection from diabetic mice. A primary signal path involved in the promoted healing effect was further illustrated by comprehensive assays of immunohistochemical evaluation, Western blot, and quantitative polymerase chain reaction. Taken together, our AuAgCu2O NSs are shown to be potent candidates for clinical utilization in the treatment of diabetic epithelium injuries.

    View details for DOI 10.1021/acsnano.9b08930

    View details for PubMedID 32048825

  • Potent and durable antibacterial activity of ZnO-dotted nanohybrids hydrothermally derived from ZnAl-layered double hydroxides COLLOIDS AND SURFACES B-BIOINTERFACES Li, M., Xu, Z., Sultanbawa, Y., Chen, W., Liu, J., Qian, G. 2019; 181: 585?92

    Abstract

    The search for effective alternatives to traditional antibiotics to avoid antibiotic resistant bacteria is growing worldwide. ZnO nanoparticles are found to effectively inhibit growth and proliferation of bacteria, and ZnO-based layered double hydroxides (ZnO-based LDHs) have been intensively investigated for this purpose. However, the nanocomposites are made in a multi-step preparation process with severe agglomeration and limited bactericidal ability. In this research, ZnO-dotted nanohybrids using Zn3Al-LDHs as precursors (ZnO-dotted LDHs or ZnO/LDHs) were synthesized under facile hydrothermal conditions. An understanding of the transformation of the LDH precursors to the ZnO/LDHs was conducted with TEM/HRTEM/XRD/FTIR. ZnO/LDHs can be transformed from ZnAl-LDHs, with more ZnO nanodots generated upon heating at 150 and 200?°C for 2?h (Zn3Al-150, Zn3Al-200). Zn3Al-200 nanohybrids showed potent antibacterial activity towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at 100-300??g/mL for 4 days. Antibacterial activity of Zn3Al-200 may be attributed to the synergistic effects (ROS, leached Zn2+ and physical interaction). This research thus suggests a potential economic approach to prepare ZnO/LDH nanocomposites for avoiding the antibiotic resistant bacteria in environmental engineering or clinic fields.

    View details for DOI 10.1016/j.colsurfb.2019.06.013

    View details for Web of Science ID 000481565300068

    View details for PubMedID 31195314

  • PD-L1 Distribution and Perspective for Cancer Immunotherapy-Blockade, Knockdown, or Inhibition FRONTIERS IN IMMUNOLOGY Wu, Y., Chen, W., Xu, Z., Gu, W. 2019; 10: 2022

    Abstract

    Cancer immunotherapy involves blocking the interactions between the PD-1/PD-L1 immune checkpoints with antibodies. This has shown unprecedented positive outcomes in clinics. Particularly, the PD-L1 antibody therapy has shown the efficiency in blocking membrane PD-L1 and efficacy in treating some advanced carcinoma. However, this therapy has limited effects on many solid tumors, suspecting to be relevant to PD-L1 located in other cellular compartments, where they play additional roles and are associated with poor prognosis. In this review, we highlight the advances of 3 current strategies on PD-1/PD-L1 based immunotherapy, summarize cellular distribution of PD-L1, and review the versatile functions of intracellular PD-L1. The intracellular distribution and function of PD-L1 may indicate why not all antibody blockade is able to fully stop PD-L1 biological functions and effectively inhibit tumor growth. In this regard, gene silencing may have advantages over antibody blockade on suppression of PD-L1 sources and functions. Apart from cancer cells, PD-L1 silencing on host immune cells such as APC and DC can also enhance T cell immunity, leading to tumor clearance. Moreover, the molecular regulation of PD-L1 expression in cells is being elucidated, which helps identify potential therapeutic molecules to target PD-L1 production and improve clinical outcomes. Based on our understandings of PD-L1 distribution, regulation, and function, we prospect that the more effective PD-L1-based cancer immunotherapy will be combination therapies.

    View details for DOI 10.3389/fimmu.2019.02022

    View details for Web of Science ID 000482818900001

    View details for PubMedID 31507611

    View details for PubMedCentralID PMC6718566

  • Ceria Nanoparticles Meet Hepatic Ischemia-Reperfusion Injury: The Perfect Imperfection ADVANCED MATERIALS Ni, D., Wei, H., Chen, W., Bao, Q., Rosenkrans, Z. T., Barnhart, T. E., Ferreira, C. A., Wang, Y., Yao, H., Sun, T., Jiang, D., Li, S., Cao, T., Liu, Z., Engle, J. W., Hu, P., Lan, X., Cai, W. 2019; 31 (40): e1902956

    Abstract

    The mononuclear phagocyte system (MPS, e.g., liver, spleen) is often treated as a "blackbox" by nanoresearchers in translating nanomedicines. Often, most of the injected nanomaterials are sequestered by the MPS, preventing their delivery to the desired disease areas. Here, this imperfection is exploited by applying nano-antioxidants with preferential liver uptake to directly prevent hepatic ischemia-reperfusion injury (IRI), which is a reactive oxygen species (ROS)-related disease. Ceria nanoparticles (NPs) are selected as a representative nano-antioxidant and the detailed mechanism of preventing IRI is investigated. It is found that ceria NPs effectively alleviate the clinical symptoms of hepatic IRI by scavenging ROS, inhibiting activation of Kupffer cells and monocyte/macrophage cells. The released pro-inflammatory cytokines are then significantly reduced and the recruitment and infiltration of neutrophils are minimized, which suppress subsequent inflammatory reaction involved in the liver. The protective effect of nano-antioxidants against hepatic IRI in living animals and the revealed mechanism herein suggests their future use for the treatment of hepatic IRI in the clinic.

    View details for DOI 10.1002/adma.201902956

    View details for Web of Science ID 000481321200001

    View details for PubMedID 31418951

    View details for PubMedCentralID PMC6773480

  • High and long-term antibacterial activity against Escherichia coli via synergy between the antibiotic penicillin G and its carrier ZnAl layered double hydroxide COLLOIDS AND SURFACES B-BIOINTERFACES Li, M., Sultanbawa, Y., Xu, Z., Gu, W., Chen, W., Liu, J., Qian, G. 2019; 174: 435?42

    Abstract

    Antibiotic-resistant bacterial infections are a global health problem. A commonly-used antibiotic Penicillin G was incorporated into ZnAl-layered double hydroxides (PNG/LDH) with a varied amount of PNG. PNG/LDH nanocomposites were well characterized in structure and composition using elemental analysis, X-ray diffraction pattern, Fourier transform infrared spectroscopy and TEM images, revealing that PNG were mostly adsorbed on the LDH surfaces at a lower PNG loading but some were intercalated into LDH interlayers at a higher PNG loading. The typical release profile of PNG and Zn2+ from PNG/LDH was a quick release, followed by a sustainable slow release. The antibacterial tests against Escherichia coli demonstrated that PNG/LDH with a suitable composition synergistically improved bacterial inhibition compared with free PNG and pristine LDHs. In specific, PNG/LDH with much higher cost-effectiveness showed a potent antimicrobial activity and maintained the activity for up to 10 days, significantly elongating the antibacterial effect compared with just 1 day for free PNG in the same conditions. Our results suggest suitable composition of nanoparticle carriers and antibiotics could significantly enhance antibacterial activity of antibiotics for a long period via the synergistic effect between carrier and antibiotics, a potential approach to overcome the bacterial resistance to antibiotics.

    View details for DOI 10.1016/j.colsurfb.2018.11.035

    View details for Web of Science ID 000459840800051

    View details for PubMedID 30481704

  • Biodistribution of PNIPAM-Coated Nanostructures Synthesized by the TDMT Method Gu, W., Bobrini, V. A., Chen, S. R., Wang, Z., Schoning, J. P., Gu, Y., Chen, W., Chen, M., Jia, Z., Monteiro, M. J. AMER CHEMICAL SOC. 2019: 625?34

    Abstract

    Targeting the spleen with nanoparticles could increase the efficacy of vaccines and cancer immunotherapy, and have the potential to treat intracellular infections including leishmaniasis, trypanosome, splenic TB, AIDS, malaria, and hematological disorders. Although, nanoparticle capture in both the liver and spleen has been well documented, there are only a few examples of specific capture in the spleen alone. It is proposed that the larger the nanoparticle size (>400 nm) the greater the specificity and capture within the spleen. Here, we synthesized five nanostructures with different shapes (ranging from spheres, worms, rods, nanorattles, and toroids) and poly( N-isopropylacrylamide), PNIPAM, surface coating using the temperature-directed morphology transformation (TDMT) method. Globular PNIPAM (i.e., water insoluble) surface coatings have been shown to significantly increase cell uptake and enhanced enzyme activity. We incorporated a globular component of PNIPAM on the nanostructure surface and examined the in vivo biodistribution of these nanostructures and accumulation in various tissues and organs in a mouse model. The in vivo biodistribution as a function of time was influenced by the shape and PNIPAM surface composition, in which organ capture and retention was the highest in the spleen. The rods (?150 nm in length and 15 nm in width) showed the highest capture and retention of greater than 35% to the initial injection amount compared to all other nanostructures. It was found that the rods specifically targeted the cells in the red pulp region of the spleen due to the shape and PNIPAM coating of the rod. This remarkable accumulation and selectively into the spleen represents new nanoparticle design parameters to develop new splenotropic effects for vaccines and other therapeutics.

    View details for DOI 10.1021/acs.biomac.8b01196

    View details for Web of Science ID 000458937200006

    View details for PubMedID 30157649

  • C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma. FASEB journal : official publication of the Federation of American Societies for Experimental Biology Nabizadeh, J. A., Manthey, H. D., Panagides, N., Steyn, F. J., Lee, J. D., Li, X. X., Akhir, F. N., Chen, W., Boyle, G. M., Taylor, S. M., Woodruff, T. M., Rolfe, B. E. 2019; 33 (10): 11060?71

    Abstract

    The canonical complement component 5a (C5a) receptor (C5aR) 1 has well-described roles in tumorigenesis but the contribution of the second receptor, C5aR2, is unclear. The present study demonstrates that B16.F0 melanoma cells express mRNA for both C5aR1 and C5aR2 and signal through ERK and p38 MAPKs in response to C5a. Despite this, C5a had no impact on melanoma cell proliferation or migration in vitro. In vivo studies demonstrated that the growth of B16.F0 melanoma tumors was increased in C5aR2-/- mice but reduced in C5aR1-/- mice and wild-type mice treated with a C5aR1 antagonist. Analysis of tumor-infiltrating leukocyte populations showed no significant differences between wild-type and C5aR2-/- mice. Conversely, percentages of myeloid-derived suppressor cells, macrophages, and regulatory T lymphocytes were lower in tumors from C5aR1-/- mice, whereas total (CD3+) T lymphocytes and CD4+ subsets were higher. Analysis of cytokine and chemokine levels also showed plasma IFN-? was higher and tumor C-C motif chemokine ligand 2 was lower in the absence of C5aR1. The results suggest that C5aR1 signaling supports melanoma growth by promoting infiltration of immunosuppressive leukocyte populations into the tumor microenvironment, whereas C5aR2 has a more restricted but beneficial role in limiting tumor growth. Overall, these data support the potential of C5aR1-inhibitory therapies for melanoma.-Nabizadeh, J. A., Manthey, H. D., Panagides, N., Steyn, F. J., Lee, J. D., Li, X. X., Akhir, F. N. M., Chen, W., Boyle, G. M., Taylor, S. M., Woodruff, T. M., Rolfe, B. E. C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma.

    View details for DOI 10.1096/fj.201800980RR

    View details for PubMedID 31298935

  • Smart H2S?Triggered/Therapeutic System (SHTS)?Based Nanomedicine Advanced Science Chen, W., Ni, D., Rosenkrans, Z., Cao, T., Cai, W. 2019

    View details for DOI 10.1002/advs.201901724

  • Immuno-PET imaging of VEGFR-2 expression in prostate cancer with 89Zr-labeled ramucirumab. American journal of cancer research Li, M., Jiang, D., Barnhart, T. E., Cao, T., Engle, J. W., Chen, W., Cai, W. 2019; 9 (9): 2037?46

    Abstract

    The detection and monitoring of prostate cancer (PrCa) malignancies using most of the conventional strategies is challenging. As an over-expressed biomarker of PrCa, the vascular endothelial growth factor receptor 2 (VEGFR-2) can be delineated by non-invasive imaging to address such issue. Herein, we report the positron emission tomography (PET) of VEGFR-2 expression in a PrCa mice models by composing a novel tracer, [89Zr]zirconium-labeled clinical VEGFR-2 antibody (Ramucirumab), i.e. 89Zr-Df-R. The VEGFR-2 expression levels among three different PrCa cell lines (PC-3, LNCAP and LAPC-4) were confirmed by flow cytometry. The immuno-PET imaging and bio-distribution (Bio-D) study were conducted in subcutaneous PrCa mice models via the 89Zr-Df-R. The regions of interest (ROI) data showed that the uptake of 89Zr-Df-R in the positive PC-3 (9.5±3 %ID/g) tumors are obviously higher than those ones in the negative LNCAP (6.0±1.7 %ID/g) or LAPC-4 (4.3±0.7 %ID/g) tumors at 120 hours post-injection, while the accumulation of 89Zr-Df-R in PC-3 tumors (4.3±1.2 %ID/g)) could be significantly reduced by the blockade of unlabeled Ramucirumab. These quantitative data coincide with the Bio-D data and proves the specificity. Additionally, the immuno-fluorescent staining results confirmed the expression pattern of VEGFR-2 among various PrCa tumors. Finally, the flow cytometry of PC-3 tumor tissue further proved that the binding of 89Zr-Df-R to VEGFR-2 primarily occurs on the PC-3 tumor cells. In summary, the description of the VEGFR-2 expression in PrCa by in-vivo PET with 89Zr-Df-R is feasible and it may shed light on the early detection of foci and dynamic monitoring of anti-VEGFR-2 therapy in PrCa.

    View details for PubMedID 31598404

  • Clay nanoparticles co-deliver three antigens to promote potent immune responses against pathogenic Escherichia coli JOURNAL OF CONTROLLED RELEASE Chen, W., Zuo, H., Rolfe, B., Schembri, M. A., Cobbold, R. N., Zhang, B., Mahony, T. J., Xu, Z. 2018; 292: 196?209

    Abstract

    Currently, there are few strategies for controlling pathogenic bacteria, especially the pathotypes of Escherichia coli which are an emerging threat to public health worldwide. Here, multivalent vaccine formulations are reported for control of pathogenic E. coli. The formulations utilised clay nanoparticles, either layered double hydroxides (LDH) or hectorite (HEC), to complex with a cocktail of three recombinant antigens, intimin ? (IB), proprietary antigen 1 (PAg1) and proprietary antigen 2 (PAg2). Acting as nano-adjuvants, LDH and HEC were able to stimulate strong, durable and balanced immune responses in mice. Moreover, LDH-IB-PAg1-PAg2 and HEC-IB-PAg1-PAg2 immunised mice developed potent mucosal immune responses and efficiently prevented adherence of enterohemorrhagic E. coli serotype O26 to mammalian cells. Notably, the multi-faceted immune responses elicited by the clay nanoparticle formulations were significantly higher than those induced by a QuilA formulation, without antigenic competition observed for the first time. The results of this study suggest that LDH and HEC offer considerable promise as effective multivalent vaccine carriers against important pathogens such as enteropathogenic E. coli.

    View details for DOI 10.1016/j.jconrel.2018.11.008

    View details for Web of Science ID 000452348100016

    View details for PubMedID 30414464

  • Novel theranostic nanoplatform for complete mice tumor elimination via MR imaging-guided acid-enhanced photothermo-/chemo-therapy BIOMATERIALS Li, B., Tang, J., Chen, W., Hao, G., Kurniawan, N., Gu, Z., Xu, Z. 2018; 177: 40?51

    Abstract

    Non-invasive imaging-guided tumor therapy requires new-generation bio-nanomaterials to sensitively respond to the unique tumor microenvironment for precise diagnosis and efficient treatment. Here, we report such a theranostic nanoplatform by engineering defect-rich multifunctional Cu-doped layered double hydroxide (Cu-LDH) nanoparticles, which integrates pH-sensitive T1-magnetic resonance imaging (MRI), acid-enhanced photothermal therapy and heat-facilitated chemotherapy. As characterized with EXAFS and XPS, smaller Cu-LDH nanoparticles possess a considerable amount of defects around Cu cations, an advantageous microstructure that enables a high photothermal conversion of 808?nm NIR laser (53.1%). The exposure of CuOH octahedra on the LDH surface makes the photothermal conversion significantly acid-enhanced (53.1% at pH 7.0 vs. 81.9% at pH 5.0). This Cu peculiar microstructure also makes T1-MRI very pH-sensitive, a desirable guide for subsequent tumor photothermal therapy. Combined photothermal therapy and chemotherapy lead to nearly complete elimination of tumor tissues in vivo with a low injection dose of agents. Therefore, this novel defect-rich Cu-LDH nanoplatform is one of promising tumor-specific nanotheranostic agents for non-invasive imaging-guided combinational therapy.

    View details for DOI 10.1016/j.biomaterials.2018.05.055

    View details for Web of Science ID 000439401700004

    View details for PubMedID 29883915

  • Brain Targeting Delivery Facilitated by Ligand-Functionalized Layered Double Hydroxide Nanoparticles ACS APPLIED MATERIALS & INTERFACES Chen, W., Zuo, H., Zhang, E., Li, L., Henrich-Noack, P., Cooper, H., Qian, Y., Xu, Z. 2018; 10 (24): 20326?33

    Abstract

    A delivery platform with highly selective permeability through the blood-brain barrier (BBB) is essential for brain disease treatment. In this research, we designed and prepared a novel target nanoplatform, that is, layered double hydroxide (LDH) nanoparticle conjugated with targeting peptide-ligand Angiopep-2 (Ang2) or rabies virus glycoprotein (RVG) via intermatrix bovine serum albumin for brain targeting. In vitro studies show that functionalization with the target ligand significantly increases the delivery efficiency of LDH nanoparticles to the brain endothelial (bEnd.3) cells and the transcytosis through the simulated BBB model, that is, bEnd.3 cell-constructed multilayer membrane. In vivo confocal neuroimaging of the rat's blood-retina area dynamically demonstrates that LDH nanoparticles modified with peptide ligands have shown a prolonged retention period within the retina vessel in comparison with the pristine LDH group. Moreover, Ang2-modified LDH nanoparticles are found to more specifically accumulate in the mouse brain than the control and RVG-modified LDH nanoparticles after 2 and 48 h intravenous injection. All these findings strongly suggest that Ang2-modified LDHs can serve as an effective targeting nanoplatform for brain disease treatment.

    View details for DOI 10.1021/acsami.8b04613

    View details for Web of Science ID 000436211500014

    View details for PubMedID 29799186

  • Clay Nanoparticles Elicit Long-Term Immune Responses by Forming Biodegradable Depots for Sustained Antigen Stimulation SMALL Chen, W., Zuo, H., Li, B., Duan, C., Rolfe, B., Zhang, B., Mahony, T. J., Xu, Z. 2018; 14 (19): e1704465

    Abstract

    Nanomaterials have been widely tested as new generation vaccine adjuvants, but few evoke efficient immunoreactions. Clay nanoparticles, for example, layered double hydroxide (LDH) and hectorite (HEC) nanoparticles, have shown their potent adjuvanticity in generating effective and durable immune responses. However, the mechanism by which clay nanoadjuvants stimulate the immune system is not well understood. Here, it is demonstrated that LDH and HEC-antigen complexes form loose agglomerates in culture medium/serum. They also form nodules with loose structures in tissue after subcutaneous injection, where they act as a depot for up to 35 d. More importantly, clay nanoparticles actively and continuously recruit immune cells into the depot for up to one month, and stimulate stronger immune responses than FDA-approved adjuvants, Alum and QuilA. Sustained antigen release is also observed in clay nanoparticle depots, with 50-60% antigen released after 35 d. In contrast, Alum-antigen complexes show minimal antigen release from the depot. Importantly, LDH and HEC are more effective than QuilA and Alum in promoting memory T-cell proliferation. These findings suggest that both clay nanoadjuvants can serve as active vaccine platforms for sustained and potent immune responses.

    View details for DOI 10.1002/smll.201704465

    View details for Web of Science ID 000432032800015

    View details for PubMedID 29655306

  • Efficient induction of comprehensive immune responses to control pathogenic E. coli by clay nano-adjuvant with the moderate size and surface charge SCIENTIFIC REPORTS Chen, W., Zuo, H., Mahony, T. J., Zhang, B., Rolfe, B., Xu, Z. 2017; 7: 13367

    Abstract

    In recent decades, diseases caused by pathogenic Escherichia coli (E. coli), enterohaemorrhagic E. coli (EHEC) O26 have been increasingly reported worldwide, which are as severe as those caused by EHEC strain O157:H7 and require effective intervention strategies. Herein, we report the application of clay nanoparticles, i.e. hectorites as effective nano-adjuvants for vaccination against EHEC O26 colonization. We show that medium size HEC (hectorite, around 73~77?nm diameter) is able to induce efficient humoral and cellular immune responses against EHEC antigen - intimin ? (IB), which are significantly higher than those triggered by commercially used adjuvants - QuilA and Alum. We also demonstrate that mice immunized with IB adjuvanted with HEC nanoparticles elicit sufficient secretion of mucosal IgA, capable of providing effective protection against EHEC O26 binding to ruminant and human cells. In addition, we demonstrate for the first time that hectorites are able to initiate maturation of RAW 264.7 macrophages, inducing expression of co-stimulatory cytokines at a low nanoparticle concentration (10??g/mL). Together these data strongly suggest that hectorite with optimized size is a highly efficient vaccine nano-adjuvant.

    View details for DOI 10.1038/s41598-017-13570-2

    View details for Web of Science ID 000413084800064

    View details for PubMedID 29042573

    View details for PubMedCentralID PMC5645426

  • MnAl Layered Double Hydroxide Nanoparticles as a Dual-Functional Platform for Magnetic Resonance Imaging and siRNA Delivery CHEMISTRY-A EUROPEAN JOURNAL Zuo, H., Chen, W., Li, B., Xu, K., Cooper, H., Gu, Z., Xu, Z. 2017; 23 (57): 14299?306

    Abstract

    Multifunctional nanoparticles for cancer theranosis have been widely explored for effective cancer detection and therapy. In this work, dually functionalised manganese-based layered double hydroxide nanoparticles (Mn-LDH) were examined as an effective anticancer drug/gene delivery system and for T1 -weighted magnetic resonance imaging (MRI) in brain cancer theranostics. Such Mn-LDH have been shown to accommodate dsDNA/siRNAs and efficiently deliver them to Neuro-2a cells (N2a). Mn-LDH have also shown high biocompatibility with low cytotoxicity. Importantly, the cell-death siRNA (CD-siRNA) delivered with Mn-LDH more efficiently kills brain cancer cells than the free CD-siRNA. Moreover, Mn-LDH can act as excellent contrast agents for MRI, with an r1 value of 4.47?mm-1 ?s-1 , which is even higher than that of commercial contrast agents based on Gd complexes (r1 =3.4?mm-1 ?s-1 ). Altogether, the high delivery efficacy and MRI contrast capability make dual-functional Mn-LDH potential bimodal agents for simultaneous cancer diagnosis and therapy.

    View details for DOI 10.1002/chem.201702835

    View details for Web of Science ID 000412819400026

    View details for PubMedID 28762580

  • Shape-Controlled Hollow Mesoporous Silica Nanoparticles with Multifunctional Capping for In Vitro Cancer Treatment CHEMISTRY-A EUROPEAN JOURNAL Geng, H., Chen, W., Xu, Z., Qian, G., An, J., Zhang, H. 2017; 23 (45): 10878?85

    Abstract

    A series of multifunctional shape-controlled nonspherical hollow mesoporous silica nanoparticles (HMSNs) drug carriers have been prepared by employing Fe2 O3 with four morphologies (capsule, cube, rice, and rhombus) as a sacrificial template and a multifunctional cap as the encapsulating shell. The resulting shape-controlled nonspherical HMSNs perfectly replicate the original morphology of the Fe2 O3 templates, which possess a high specific surface area, good monodispersity, perpendicular mesoporous channels, and excellent biocompatibility. After modification of polyethylene glycol (PEG) and folic acid (FA), the shape-controlled HMSN core and functional shell can then be integrated into a single device (HMSNs-PEG-FA) to provide an efficient and tumor-cell-selective drug-delivery system. The shape-controlled HMSNs and HMSNs-PEG-FA all show controlled pH-responsive release behavior for the anticancer drug doxorubicin hydrochloride (DOX). The in vitro results indicate that HMSNs-PEG-FA is biocompatible and selectively targets HeLa cells (overexpressed folate receptors). Fluorescence images show that desirable surface modification and the nonspherical shape effectively facilitate cellular internalization of HMSNs. It is expected that the construction of these unique nanomaterials with controlled morphology through the hard-templating technique may also provide useful information for the design of nanoscale multifunctional systems.

    View details for DOI 10.1002/chem.201701806

    View details for Web of Science ID 000407397300025

    View details for PubMedID 28580592

  • Manganese-Based Layered Double Hydroxide Nanoparticles as a T-1-MRI Contrast Agent with Ultrasensitive pH Response and High Relaxivity ADVANCED MATERIALS Li, B., Gu, Z., Kurniawan, N., Chen, W., Xu, Z. 2017; 29 (29)

    Abstract

    Recently, Mn(II)-containing nanoparticles have been explored widely as an attractive alternative to Gd(III)-based T1 -weighted magnetic resonance imaging (MRI) contrast agents (CAs) for cancer diagnosis. However, as far as it is known, no Mn-based MRI CAs have been reported to sensitively respond to a very weakly acidic environment (pH 6.5-7.0, i.e., the pH range in a tumor microenvironment) with satisfactory imaging performance. Here, recently devised pH-ultrasensitive Mn-based layered double hydroxide (Mn-LDH) nanoparticles with superb longitudinal relaxivity (9.48 mm-1 s-1 at pH 5.0 and 6.82 mm-1 s-1 at pH 7.0 vs 1.16 mm-1 s-1 at pH 7.4) are reported, which may result from the unique microstructure of Mn ions in Mn-LDH, as demonstrated by extended X-ray absorption fine structure. Further in vivo imaging reveals that Mn-LDH nanoparticles show clear MR imaging for tumor tissues in mice for 2 d post intravenous injection. Thus, this novel Mn-doped LDH nanomaterial, together with already demonstrated capacity for drug and gene delivery, is a very potential theranostic agent for cancer diagnosis and treatment.

    View details for DOI 10.1002/adma.201700373

    View details for Web of Science ID 000406677900012

    View details for PubMedID 28585312

  • A Facile Way of Modifying Layered Double Hydroxide Nanoparticles with Targeting Ligand-Conjugated Albumin for Enhanced Delivery to Brain Tumour Cells ACS APPLIED MATERIALS & INTERFACES Zuo, H., Chen, W., Cooper, H. M., Xu, Z. 2017; 9 (24): 20444?53

    Abstract

    Active targeting of nanoparticles (NPs) for cancer treatment has attracted increasing interest in the past decades. Various ligand modification strategies have been used to enhance the targeting of NPs to the tumor site. However, how to reproducibly fabricate diverse targeting NPs with narrowly changeable biophysiochemical properties remains as a major challenge. In this study, layered double hydroxide (LDH) NPs were modified as a target delivery system. Two brain tumor targeting ligands, i.e., angiopep-2 and rabies virus glycoprotein, were conjugated to the LDH NPs via an intermatrix protein moiety, bovine serum albumin (BSA), simultaneously endowing the LDHs with excellent colloidal stability and targeting capability. The ligands were first covalently linked with BSA through the heterobifunctional cross-linker sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate. Then, the ligand-linked BSA and pristine BSA were together coated onto the surface of LDHs through electrostatic interaction, followed by cross-linking with the cross-linker glutaraldehyde to immobilize these BSAs on the LDH surface. In this way, we are able to readily prepare colloidally stabilized tumor-targeted LDH NPs. The targeting efficacy of the ligand-conjugated LDH delivery system has been evidenced in the uptake by two neutral cells (U87 and N2a) compared to unmodified LDHs. This new approach provides a promising strategy for rational design and preparation of target nanoparticles as a selective and effective therapeutic treatment for brain tumors.

    View details for DOI 10.1021/acsami.7b06421

    View details for Web of Science ID 000404090000020

    View details for PubMedID 28574700

  • The Complement C3a Receptor Contributes to Melanoma Tumorigenesis by Inhibiting Neutrophil and CD4(+) T Cell Responses JOURNAL OF IMMUNOLOGY Nabizadeh, J. A., Manthey, H. D., Steyn, F. J., Chen, W., Widiapradja, A., Akhir, F., Boyle, G. M., Taylor, S. M., Woodruff, T. M., Rolfe, B. E. 2016; 196 (11): 4783?92

    Abstract

    The complement peptide C3a is a key component of the innate immune system and a major fragment produced following complement activation. We used a murine model of melanoma (B16-F0) to identify a hitherto unknown role for C3a-C3aR signaling in promoting tumor growth. The results show that the development and growth of B16-F0 melanomas is retarded in mice lacking C3aR, whereas growth of established melanomas can be arrested by C3aR antagonism. Flow cytometric analysis showed alterations in tumor-infiltrating leukocytes in the absence of C3aR. Specifically, neutrophils and CD4(+) T lymphocyte subpopulations were increased, whereas macrophages were reduced. The central role of neutrophils was confirmed by depletion experiments that reversed the tumor inhibitory effects observed in C3aR-deficient mice and returned tumor-infiltrating CD4(+) T cells to control levels. Analysis of the tumor microenvironment showed upregulation of inflammatory genes that may contribute to the enhanced antitumor response observed in C3aR-deficient mice. C3aR deficiency/inhibition was also protective in murine models of BRAF(V600E) mutant melanoma and colon and breast cancer, suggesting a tumor-promoting role for C3aR signaling in a range of tumor types. We propose that C3aR activation alters the tumor inflammatory milieu, thereby promoting tumor growth. Therapeutic inhibition of C3aR may therefore be an effective means to trigger an antitumor response in melanoma and other cancers.

    View details for DOI 10.4049/jimmunol.1600210

    View details for Web of Science ID 000377676000038

    View details for PubMedID 27183625

  • Efficient and Durable Vaccine against Intimin beta of Diarrheagenic E-Coli Induced by Clay Nanoparticles SMALL Chen, W., Zhang, B., Mahony, T., Gu, W., Rolfe, B., Xu, Z. 2016; 12 (12): 1627?39

    Abstract

    Improved strategies are urgently required to control infections with enterohemorrhagic Escherichia coli and enteropathogenic E. coli, two dominant zoonotic enteric pathogens responsible for a wide spectrum of illnesses as well as deaths of human being, with tremendous financial cost worldwide. The present study investigates the capacity of two clay nanoparticles (NPs) with opposite surface charges, namely synthetic layered double hydroxide (LDH) and hectorite (HEC) NPs as adjuvants to promote strong immune responses against the infections. Here both LDH and HEC NPs are showed to be able to carry an appreciable amount of Intimin ? (1.1 and 4.4 mg per mg clay nanomaterials, respectively) and significantly facilitate antigen uptake by antigen-presenting cells. Remarkably, these clay NPs induce strong antibody and cell-mediated immune responses, which are much higher than that by the potent adjuvant, QuilA. Furthermore, these strong immune responses are well maintained for at least four months in the mouse model, during which there are no changes in histopathology of the animal organs. Collectively these data demonstrate the suitability of LDH and HEC NPs as useful adjuvants in new-generation vaccine formulations to control various infectious diseases.

    View details for DOI 10.1002/smll.201503359

    View details for Web of Science ID 000373123100007

    View details for PubMedID 27000499

  • Identification of the interaction domains of white spot syndrome virus envelope proteins VP28 and VP24 VIRUS RESEARCH Li, Z., Chen, W., Xu, L., Li, F., Yang, F. 2015; 200: 24?29

    Abstract

    VP28 and VP24 are two major envelope proteins of white spot syndrome virus (WSSV). The direct interaction between VP28 and VP24 has been described in previous studies. In this study, we confirmed this interaction and mapped the interaction domains of VP28 and VP24 by constructing a series of deletion mutants. By co-immunoprecipitation, two VP28-binding domains of VP24 were located at amino acid residues 46-61 and 148-160, while VP24-binding domain of VP28 was located at amino acid residues 31-45. These binding domains were further corroborated by peptide blocking assay, in which synthetic peptides spanning the binding domains were able to inhibit VP28-VP24 interaction, whereas same-size control peptides from non-binging regions did not.

    View details for DOI 10.1016/j.virusres.2015.01.017

    View details for Web of Science ID 000351798800004

    View details for PubMedID 25637460

  • Co-delivery of siRNAs and anti-cancer drugs using layered double hydroxide nanoparticles BIOMATERIALS Li, L., Gu, W., Chen, J., Chen, W., Xu, Z. P. 2014; 35 (10): 3331?39

    Abstract

    In this research we employed layered double hydroxide nanoparticles (LDHs) to simultaneously deliver an anticancer drug 5-fluorouracil (5-FU) and Allstars Cell Death siRNA (CD-siRNA) for effective cancer treatment. The strategy takes advantage of the LDH anion exchange capacity to intercalate 5-FU into its interlayer spacing and load siRNA on the surface of LDH nanoparticles. LDH nanoparticles have been previously demonstrated as an effective cellular delivery system for 5-FU and siRNA separately in various investigations. More excitedly, the combination of CD-siRNA and anticancer drug 5-FU with the same LDH particles significantly enhanced cytotoxicity to three cancer cell lines, e.g. MCF-7, U2OS and HCT-116, compared to the single treatment with either CD-siRNA or 5-FU. This enhancement is probably a result of coordinate mitochondrial damage process. Thus, the strategy to co-deliver siRNA and an anticancer drug by LDHs has great potential to overcome the drug resistance and enhance cancer treatment.

    View details for DOI 10.1016/j.biomaterials.2013.12.095

    View details for Web of Science ID 000332188400019

    View details for PubMedID 24456604

  • Effects of high salinity, high temperature and pH on capsid structure of white spot syndrome virus DISEASES OF AQUATIC ORGANISMS Chen, W., Zhang, H., Gu, L., Li, F., Yang, F. 2012; 101 (2): 167?71

    Abstract

    The structural stability of white spot syndrome virus (WSSV) capsids at high salinity, high temperature and various pH values was studied. To obtain the viral capsids, the nucleocapsids were treated with high salinity. The results showed that high salinity treatment can cause the dissociation of VP15 and most of VP95 from the nucleocapsid, but there were no noticeable alterations in morphology and ultrastructure of the nucleocapsid and capsid. The capsids retained morphological integrity at temperatures <45°C but became aberrant at >60°C. In addition, the capsids were relatively resistant to strong acid conditions and were tolerant to a broad pH range of 1 to 10. However, morphological change occurred at pH 10.5. The capsids broke up into small pieces at pH 11 and completely degraded in 0.1 and 1.0 M NaOH. These results indicated that the WSSV capsid is acid-stable and alkali-labile.

    View details for DOI 10.3354/dao02511

    View details for Web of Science ID 000310843100010

    View details for PubMedID 23135144

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