4 results for Akagi, J

  • Interfacing cell-based assays in environmental scanning electron microscopy using dielectrophoresis

    Khoshmanesh, K; Akagi, J; Nahavandi, S; Kalantar-Zadeh, K; Baratchi, S; Williams, David; Cooper, JM; Wlodkowic, Donald (2011)

    Journal article
    The University of Auckland Library

    Development of the dielectrophoretic (DEP) live cell trapping technology and its interfacing with the environmental scanning electron microscopy (ESEM) is described. DEP microelectrode arrays were fabricated on glass substrate using photolithography and lift-off. Chip-based arrays were applied for ESEM analysis of DEP-trapped human leukemic cells. This work provides proof-of-concept interfacing of the DEP cell retention and trapping technology with ESEM to provide a high-resolution analysis of individual nonadherent cells.

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  • Integration of single-cell microfluidic cell culture with mass spectrometry

    Wlodkowic, Donald; Wright, BEW; Green, M; Akagi, J; Greenwood, D; Villas-Boas, SVB; Williams, DEW (2011)

    Conference item
    The University of Auckland Library

    Microfluidic systems can be constructed on the same scale as single cells, w ith features in the range of 1-100 μm, and with high spatial and temporal control of culture conditions. [1] High-resolution mass spectrometry is the premier tool for the study of proteomics and metabolomics. [2] Integrating the two will enable the evaluation of the physiology of single cells in prescribed culture conditions, leading to advances in research on single cell variability, and the effect of culture conditions, localised environment and perturbations. Toward this end, we have developed integrated microfluidic systems capable of capturing and housing the culture of a single cell using polydimethysiloxane (PDMS) based microfluidics (Figure 1A) and integrated them w ith novel monolithic PDMS electrospray ionisation (ESI) emitters (Figure 1B). [3] We have characterised the fully integrated cell traps/ESI emitters using both test solutions and in trial runs on cells using a Thermo LTQ-FT (hybrid ion trap / Fourier transform ion cyclotron resonance) mass spectrometer (Figure 1C). Initial results on the microfluidic cell traps, microfluidic-ESI characteristics, and performance of the integrated cell traps/ESI system will be presented along with a comparison with conventional nanospray- ESI w ith the integrated microfluidic system w ith emphasis placed on detection sensitivity and interference effects from PDMS.

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  • Wormometry-on-a-chip: Innovative technologies for in situ analysis of small multicellular organisms.

    Wlodkowic, Donald; Khoshmanesh, K; Akagi, J; Williams, David; Cooper, JM (2011-10)

    Journal article
    The University of Auckland Library

    Small multicellular organisms such as nematodes, fruit flies, clawed frogs, and zebrafish are emerging models for an increasing number of biomedical and environmental studies. They offer substantial advantages over cell lines and isolated tissues, providing analysis under normal physiological milieu of the whole organism. Many bioassays performed on these alternative animal models mirror with a high level of accuracy those performed on inherently low-throughput, costly, and ethically controversial mammalian models of human disease. Analysis of small model organisms in a high-throughput and high-content manner is, however, still a challenging task not easily susceptible to laboratory automation. In this context, recent advances in photonics, electronics, as well as material sciences have facilitated the emergence of miniaturized bioanalytical systems collectively known as Lab-on-a-Chip (LOC). These technologies combine micro- and nanoscale sciences, allowing the application of laminar fluid flow at ultralow volumes in spatially confined chip-based circuitry. LOC technologies are particularly advantageous for the development of a wide array of automated functionalities. The present work outlines the development of innovative miniaturized chip-based devices for the in situ analysis of small model organisms. We also introduce a new term "wormometry" to collectively distinguish these up-and-coming chip-based technologies that go far beyond the conventional meaning of the term "cytometry."

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  • Dynamic analysis of drug-induced cytotoxicity using chip-based dielectrophoretic cell immobilization technology

    Khoshmanesh, K; Akagi, J; Nahavandi, S; Skommer, Joanna; Baratchi, S; Cooper, JM; Kalantar-Zadeh, K; Williams, David; Wlodkowic, Donald (2011)

    Journal article
    The University of Auckland Library

    Quantification of programmed and accidental cell death provides useful end-points for the anticancer drug efficacy assessment. Cell death is, however, a stochastic process. Therefore, the opportunity to dynamically quantify individual cellular states is advantageous over the commonly employed static, end-point assays. In this work, we describe the development and application of a microfabricated, dielectrophoretic (DEP) cell immobilization platform for the real-time analysis of cancer drug-induced cytotoxicity. Microelectrode arrays were designed to generate weak electro-thermal vortices that support efficient drug mixing and rapid cell immobilization at the delta-shape regions of strong electric field formed between the opposite microelectrodes. We applied this technology to the dynamic analysis of hematopoietic tumor cells that represent a particular challenge for real-time imaging due to their dislodgement during image acquisition. The present study was designed to provide a comprehensive mechanistic rationale for accelerated cell-based assays on DEP chips using real-time labeling with cell permeability markers. In this context, we provide data on the complex behavior of viable vs dying cells in the DEP fields and probe the effects of DEP fields upon cell responses to anticancer drugs and overall bioassay performance. Results indicate that simple DEP cell immobilization technology can be readily applied for the dynamic analysis of investigational drugs in hematopoietic cancer cells. This ability is of particular importance in studying the outcome of patient derived cancer cells, when exposed to therapeutic drugs, as these cells are often rare and difficult to collect, purify and immobilize.

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