Bonnie Huang

Identification of cathode materials for lithium batteries guided by first-principles calculations

Lithium batteries have the highest energy density of all rechargeable batteries and are favoured in applications where low weight or small volume are desired — for example, laptop computers, cellular telephones and electric vehicles. One of the limitations of present commercial lithium batteries is the high cost of the LiCoO2 cathode material. Searches for a replacement material that, like LiCoO2, intercalates lithium ions reversibly have covered most of the known lithium/transition-metal oxides, but the number of possible mixtures of these is almost limitless, making an empirical search labourious and expensive. Here we show that first-principles calculations can instead direct the search for possible cathode materials. Through such calculations we identify a large class of new candidate materials in which non-transition metals are substituted for transition metals. The replacement with non-transition metals is driven by the realization that oxygen, rather than transition-metal ions, function as the electron acceptor upon insertion of Li. For one such material, Li(Co,Al)O2, we predict and verify experimentally that aluminium substitution raises the cell voltage while decreasing both the density of the material and its cost.

Structure-based programming of lymph-node targeting in molecular vaccines

In cancer patients, visual identification of sentinel lymph nodes (LNs) is achieved by the injection of dyes that bind avidly to endogenous albumin, targeting these compounds to LNs, where they are efficiently filtered by resident phagocytes. Here we translate this ‘albumin hitchhiking’ approach to molecular vaccines, through the synthesis of amphiphiles (amph-vaccines) comprising an antigen or adjuvant cargo linked to a lipophilic albumin-binding tail by a solubility-promoting polar polymer chain. Administration of structurally optimized CpG-DNA/peptide amph-vaccines in mice resulted in marked increases in LN accumulation and decreased systemic dissemination relative to their parent compounds, leading to 30-fold increases in T-cell priming and enhanced anti-tumour efficacy while greatly reducing systemic toxicity. Amph-vaccines provide a simple, broadly applicable strategy to simultaneously increase the potency and safety of subunit vaccines.

Engineering Nano- and Microparticles to Tune Immunity

The immune system can be a cure or cause of disease, fulfilling a protective role in attacking cancer or pathogenic microbes but also causing tissue destruction in autoimmune disorders. Thus, therapies aimed to amplify or suppress immune reactions are of great interest. However, the complex regulation of the immune system, coupled with the potential systemic side effects associated with traditional systemic drug therapies, has presented a major hurdle for the development of successful immunotherapies. Recent progress in the design of synthetic micro- and nano-particles that can target drugs, deliver imaging agents, or stimulate immune cells directly through their physical and chemical properties is leading to new approaches to deliver vaccines, promote immune responses against tumors, and suppress autoimmunity. In addition, novel strategies, such as the use of particle-laden immune cells as living targeting agents for drugs, are providing exciting new approaches for immunotherapy. This progress report describes recent advances in the design of micro- and nano-particles for immunotherapies and diagnostics.

Active targeting of chemotherapy to disseminated tumors using nanoparticle-carrying T cells

Nanoparticle-functionalized T cells actively transport a cytotoxic drug to systemic sites of lymphoma dissemination, enhancing the efficacy of antitumor chemotherapy. T cell backpacks carry chemo to tumors Getting drugs into tumors is no small feat, especially when they are disseminated throughout the body or harbored in the lymph nodes—often considered a “sanctuary” for cancer cells. Huang et al. devised a clever drug delivery system for such tumors that capitalizes on the natural movement of immune cells throughout the body. The authors first expanded T cells ex vivo under conditions that would make them home to lymphoid tissues. Then, nanocapsules loaded with a common chemotherapeutic were attached to the lymphocytes. The modified cells were infused into a mouse model of Burkitt’s lymphoma, where they carried their toxic backpacks to multiple lymphoid organs. The animals experienced not only reduced tumor burden but also prolonged survival compared with systemic therapy with the same drug. Because T cells are easily obtained from blood and are already being used in the clinic for cancer therapy, this “pharmacyte” strategy could be tailored to home to different organs, carrying unique cargos, in an effort to eradicate hard-to-reach tumors. Tumor cells disseminate into compartments that are poorly accessible from circulation, which necessitates high doses of systemic chemotherapy. However, the effectiveness of many drugs, such as the potent topoisomerase I poison SN-38, is hampered by poor pharmacokinetics. To deliver SN-38 to lymphoma tumors in vivo, we took advantage of the fact that healthy lymphocytes can be programmed to phenocopy the biodistribution of the tumor cells. In a murine model of disseminated lymphoma, we expanded autologous polyclonal T cells ex vivo under conditions that retained homing receptors mirroring lymphoma cells, and functionalized these T cells to carry SN-38–loaded nanocapsules on their surfaces. Nanocapsule-functionalized T cells were resistant to SN-38 but mediated efficient killing of lymphoma cells in vitro. Upon adoptive transfer into tumor-bearing mice, these T cells served as active vectors to deliver the chemotherapeutic into tumor-bearing lymphoid organs. Cell-mediated delivery concentrated SN-38 in lymph nodes at levels 90-fold greater than free drug systemically administered at 10-fold higher doses. The live T cell delivery approach reduced tumor burden significantly after 2 weeks of treatment and enhanced survival under conditions where free SN-38 and SN-38–loaded nanocapsules alone were ineffective. These results suggest that tissue-homing lymphocytes can serve as specific targeting agents to deliver nanoparticles into sites difficult to access from the circulation, and thus improve the therapeutic index of chemotherapeutic drugs with unfavorable pharmacokinetics.

Electrochemical evaluation of LiCoO2 synthesized by decomposition and intercalation of hydroxides for lithium-ion battery applications

LiCoO2 has been synthesized by a solid-state synthesis route involving the decomposition and intercalation of hydroxide precursors generated by precipitation and freeze-drying. Cyclic voltammetry of LiCoO2 obtained by heating at 100°C for 2h has shown this material to be electrochemically active with an initial discharge capacity of 92mAhg−1. Optimization of processing conditions reduced the firing time to as little as 2h at 800°C, producing LiCoO2 powders with high reversible capacity (142mAhg−1), good rate capability, and good cyclability. The favourable performance of this oxide powder in LiCoO2/C lithium-ion cells using the present oxide powders shows the instant synthesis route to be promising and cost-effective for lithium-ion battery applications.

Abstract 4432: Cell-mediated chemotherapeutic drug nanoparticle delivery to lymphoma tumors

Chemotherapeutics are a frontline treatment for lymphoma, but systemic drug therapy, either in free drug or nanoparticle form, achieves limited penetration of high tumor burdens in lymphoid tissues while introducing dose-limiting toxicity in off-target organs. We aim to specifically deliver chemotherapy into lymphoma tumors by conjugating chemotherapeutic-loaded nanoparticles onto the surfaces of T cells ex vivo. We hypothesize that, following adoptive transfer, the T cells will homeostatically migrate into tumor-bearing lymphoid organs while carrying their nanoparticle cargo. This cell-mediated shuttling of chemotherapeutic nanoparticles would reduce toxicity in off-target organs affected by systemically administered chemotherapy or non-cell tethered nanoparticles. In vitro T cell cultures were generated by activating splenocytes with conA and IL-2. Doxil, a clinically-approved liposomal formulation of doxorubicin (dox), was used as a model chemotherapeutic nanoparticle due to its high drug load and slow release characteristics. Doxil was functionalized with maleimide groups, which chemically conjugate to surface thiol groups on the T cells, resulting in stable liposome tethering to the surfaces of live cells. We adoptively transferred maleimide Doxil liposome-carrying Thy1.1 T cells into BL6 mice bearing disseminated GFP Emu-myc lymphoma tumors, an orthotopic model of aggressive B cell lymphoma, then assessed T cell and liposome biodistribution by whole animal imaging, flow cytometry and immunohistochemistry. Tumor burden in lymphoid organs was measured by flow cytometry. In vitro survival studies showed that activated T cells tolerate dox over a higher concentration range than lymphoma cells. This suggested a therapeutic window in which relevant doses of dox can be delivered by T cells without premature death of the carrier cell. Post adoptive transfer, T cells were detectable in lymph nodes and spleen as early as 24 h and continued to accumulate over a few days. Trafficking kinetics were similar regardless of whether T cells were unmodified or liposome-functionalized, and whether the recipients were healthy or tumor-bearing mice. Analysis of tumor-free and tumor-bearing lymphoid organs in recipients showed maleimide-Doxil liposomes localized on transferred T cells, interspersed throughout the organs. Treatment of tumor-bearing mice with maleimide Doxil-carrying T cells resulted in mild reductions in tumor burden using minute quantities of dox; ongoing studies are exploring the impact of increased dox dose per carrier T cell. In conclusion, we have demonstrated that T cells can be stably functionalized with doxorubicin liposomes and subsequently transport these liposomes into lymphoma tumors in vivo. This cell-mediated delivery approach is adaptable to other nanoparticle systems and may be a versatile technique for specific delivery of materials into lymphoid organs and lymphoma tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4432. doi:10.1158/1538-7445.AM2011-4432

Effects of Aluminum Doping on The Phase Stability and Electrochemical Properties of LiCoO 2 and LiMnO 2

Aluminum is of interest as a constituent for Li battery electrodes due to its low cost and low mass, and because ab initio calculations indicate that solid solution of LiAlO{sub 2} with LiMO{sub 2} (M = transition metal) in the {alpha}-NaFeO{sub 2} structure can increase intercalation voltage. In this study, the authors investigated the effect of Al doping on LiCoO{sub 2} and LiMnO{sub 2}. Single phase LiAl{sub y}Co{sub 1{minus}y}O{sub 2} has been synthesized up to y = 0.5 by firing homogeneous hydroxide precursors. A systematic increase in the open circuit voltage is observed with Al content. In LiAl{sub y}Mn{sub 1{minus}y}O{sub 2}, the addition of LiAlO{sub 2} stabilizes LiMnO{sub 2} in the {alpha}-NaFeO{sub 2} structure under conditions where neither endmember is stable in the structure. High reversible capacity was obtained over both a 4 V and 3 V plateau, indicating that the compound transforms to a spinel-related structure during cycling, but that the cooperative Jahn-Teller distortion is suppressed.

Efficient CRISPR/Cas9-Mediated Mutagenesis in Primary Murine T Lymphocytes

The ability to alter gene expression directly in T lymphocytes has provided a powerful tool for understanding T cell biology, signaling, and function. Manipulation of T cell clones and primary T cells has been accomplished primarily through overexpression or gene‐silencing studies using cDNAs or shRNAs, respectively, which are often delivered by retroviral or lentiviral transduction or direct transfection methods. The recent development of CRISPR/Cas9‐based mutagenesis has revolutionized genomic editing, allowing unprecedented genetic manipulation of many cell types with greater precision and ease. This article outlines a protocol for CRISPR/Cas9‐mediated mutagenesis in primary T lymphocytes from Cas9 transgenic mice using retroviral delivery of guide RNAs.