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Nanobiotechnology, IET

Issue 3 • Date September 2010

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Displaying Results 1 - 5 of 5
  • Hepatocyte growth factor incorporated chitosan nanoparticles differentiate murine bone marrow mesenchymal stem cell into hepatocytes in vitro

    Page(s): 51 - 60
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (707 KB)  

    Delivery of growth factor for the differentiation of stem cells into lineage specific cells holds great potential in regenerative medicine. Stem cell differentiation is governed by cytokines and growth factors secreted upon the organelle injury and, however, their short half-life necessitates exogenous supply. Development of suitable nanodevices using biodegradable polymers to deliver therapeutic proteins to the targeted site in a sustainable manner attracts scientists and clinicians. Here, for the first time, hepatocyte growth factor (HGF) was incorporated into chitosan nanoparticles (CNP) by ionotrophic gelation method. An average size of nanoparticles prepared was 100 nm, showing sustainable release of HGF. Cytotoxicity study did not reveal any adverse effect on bone marrow mesenchymal stem cells (MSC) up to 4 mg CNP/ml culture medium. To evaluate the effect of HGF incorporated CNP (HGF-CNP) on hepatic differentiation in in vitro, MSC were incubated with HGF-CNP and other supplements. After 21 days, fibroblast-like morphology of MSC became round-shape, a typical characteristic of hepatocyte cell. Immunofluorescence study for albumin expression confirmed the hepatic differentiation. In conclusion, HGF released from the HGF-CNP can differentiate MSC into hepatocytes, and this novel technique could also be extended to deliver therapeutic proteins for a variety of tissue regeneration. View full abstract»

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  • Nano-engineered living bacterial motors for active microfluidic mixing

    Page(s): 61 - 71
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (834 KB)  

    Active micromixers with rotating elements are attractive microfluidic actuators in many applications because of their mixing ability at a short distance. However, miniaturising the impeller design poses technical challenges including the fabrication and driving means. As a possible solution inspired by macro magnetic bar-stirrers, this study proposes the use of tethered, rotating bacteria as mixing elements. A tethered cell is a genetically engineered, harmless Escherichia coli (E. coli) attached to a surface by a single, shortened flagellum. The tethered flagellum acts as a pivot around which the entire cell body smoothly rotates. Videomicroscopy, image analysis and computational fluid dynamics (CFD) are utilised to demonstrate a proof-of-concept for the micro mixing process. Flow visualisation experiments show that a ~3~~m long tethered E. coli rotating at ~240~rpm can circulate a 1~~m polystyrene bead in the adjacent area at an average speed of nearly 4~~m/s. The Peclet (Peb) number for the stirred bead is evaluated to approximately 4. CFD simulations show that the rotary motion of a tethered E. coli rotating at 240 rpm can generate fluid velocities, up to 37 m/s bordering the cell envelop. Based on these simulations, the Strouhal number (St) is calculated to about 2. This hybrid bio-inorganic micromxer could be used as a local, disposable mixer. View full abstract»

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  • Well-defined thermo-responsive polymeric nanocapsules by a one-pot method via surface-initiated atom transfer radical copolymerisation

    Page(s): 72 - 76
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (258 KB)  

    The well-defined thermo-responsive polymeric nanocapsules were prepared by the one-pot approach via the surface-initiated atom transfer radical copolymerisation of N-isopropyl acrylamide (NIPAM) and N, N-methylenebisacylamide (MBA) from the silica nanoparticle templates after the silica templates were removed by hydrofluoric acid (HF). The diameter of the polymeric nanocapsules is in the range of 20-40 nm, characterised by transmission electron microscopy (TEM). The temperature-induced dimensional change of the thermo-responsive polymeric nanocapsules was investigated by dynamic light scattering (DLS) in aqueous solutions. The intelligent thermo-responsive polymeric nanocapsules are expected to be used for the controlled release of sensitive molecules, such as enzymes, proteins or DNA, by changing the environmental temperature. View full abstract»

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  • Terminating polyelectrolyte in multilayer films influences growth and morphology of adhering cells

    Page(s): 77 - 90
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1015 KB)  

    Polyelectrolyte films of anionic poly(sodium 4-styrenesulphonate) (PSS) and cationic poly (allylamine hydrochloride) (PAH) were constructed using layer-by-layer assembly. The authors examined the cytocompatibility of these films for future use in nanobiotechnology applications. Cell lines HEK-293 and 3T3-L1 were cultured on these films and the initial attachment, adhesion, proliferation and cytotoxicity of the cells were measured using a propidium iodide assay. The morphology and spread of the cells were measured by phase-contrast microscopy. The actin cytoskeleton was observed using fluorescent microscopy. Neither the PAH-terminated nor the PSS-terminated polyelectrolyte films were cytotoxic. The PAH-terminated polyelectrolyte films improved the initial attachment and subsequent adhesion of the cells, in addition to enhancing the production of extracellular matrix and the modelling of the actin filaments. The PSS-terminated film enhanced the proliferation of the cells compared to the PAH-terminated film. That was despite the cell cycle, the spreading or the cytotoxicity of both cell types being similar for either the PSS-terminated surfaces or the PAH-terminated surfaces. Cell behaviour can be modulated by the final surface charge of the polyelectrolyte film and the results are useful in guiding the choice of substrates and/or coatings for potential biomedical applications (e.g. implants) as well as cell biology research. View full abstract»

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  • Integrated circuit-based instrumentation for microchip capillary electrophoresis

    Page(s): 91 - 101
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    Although electrophoresis with laser-induced fluorescence (LIF) detection has tremendous potential in lab on chip-based point-of-care disease diagnostics, the wider use of microchip electrophoresis has been limited by the size and cost of the instrumentation. To address this challenge, the authors designed an integrated circuit (IC, i.e. a microelectronic chip, with total silicon area of <;0.25<;cm2, less than 5 mm × 5 mm, and power consumption of 28 mW), which, with a minimal additional infrastructure, can perform microchip electrophoresis with LIF detection. The present work enables extremely compact and inexpensive portable systems consisting of one or more complementary metal-oxide-semiconductor (CMOS) chips and several other low-cost components. There are, to the authors knowledge, no other reports of a CMOS-based LIF capillary electrophoresis instrument (i.e. high voltage generation, switching, control and interface circuit combined with LIF detection). This instrument is powered and controlled using a universal serial bus (USB) interface to a laptop computer. The authors demonstrate this IC in various configurations and can readily analyse the DNA produced by a standard medical diagnostic protocol (end-labelled polymerase chain reaction (PCR) product) with a limit of detection of 1 ng/ l ( 1 ng of total DNA). The authors believe that this approach may ultimately enable lab-on-a-chip-based electrophoretic instruments that cost on the order of several dollars. View full abstract»

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Aims & Scope

IET Nanobiotechnology covers all aspects of research and emerging technologies including fundamental theories and concepts applied to biomedical-related devices and methods at the micro- and nano-scale.

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