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NanoBioscience, IEEE Transactions on

Issue 3 • Date Sept. 2003

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Displaying Results 1 - 6 of 6
  • Multilayer lactate oxidase shells on colloidal carriers as engines for nanosensors

    Page(s): 133 - 137
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (301 KB) |  | HTML iconHTML  

    Self-assembly methods are being studied for construction of nanoscale chemical sensors employing coimmobilized enzymes and indicator dyes. This paper describes the assembly of the catalytic enzyme lactate oxidase in multilayer films on colloidal templates via layer-by-layer self-assembly, which is a step toward achieving nanoengineered biosensors. The architecture of the resulting films was characterized using quartz crystal microbalance and zeta potential analysis, and catalytic activity was characterized colorimetrically. The tailored activity of the functional nanofilms was proportional to the number of enzyme layers deposited during assembly, which provides a basis for designing sensors with specific interactions. View full abstract»

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  • Laser ablation patterning by interference induces directional cell growth

    Page(s): 138 - 145
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (905 KB) |  | HTML iconHTML  

    Laser-patterning by interference is a method to introduce micropatterns on the surface of TXL and TXB, which were shown to have an effect on the L929 growth. In this experiment, we have produced collagen-coated and laser-patterned TXL and TXB with different dimensions; the groove width of the line patterns varied approximately from 1.2 μm to 9.7 μm, ridge depth varied from 0.4 μm to 1.3 μm, and the groove depth varied between 0.4 μm and 1.3 μm. Therefore, a homogeneous smooth surface was achieved, and that L929 growth was only affected by the different dimensions of the line patterns. All the laser-patterned TXL and TXB have shown inducing different degrees of directional growth of L929 that the cells grew in the direction aligning the microgrooves. However, the different widths of the microgrooves were demonstrated to play an important role in determining cell morphology and growth orientation. For example, cells were elongated when they grew on the narrower widths, which were 1.26 μm, 1.91 μm, and 5.04 μm while cells tended to be triangular when grew on wider width about 9.76 μm. In addition, L929 might grow only on the top of the laser-patterns attaching the ridges when the groove widths were narrow, but might grow into the microgrooves when the width went beyond 5.04 μm. View full abstract»

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  • Exposure of magnetic bacteria to simulated mobile phone-type RF radiation has no impact on mortality

    Page(s): 146 - 149
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (238 KB) |  | HTML iconHTML  

    The interaction of mobile phone RF emissions with biogenic magnetite in the human brain has been proposed as a potential mechanism for mobile phone bioeffects. This is of particular interest in light of the discovery of magnetite in human brain tissue. Previous experiments using magnetite-containing bacteria exposed directly to emissions from a mobile phone have indicated that these emissions might be causing greater levels of cell death in these bacterial populations when compared to sham exposures. A repeat of these experiments examining only the radio frequency (RF) global system for mobile communication (GSM) component of the mobile phone signal in a well-defined waveguide system (REFLEX), shows no significant change in cell mortality compared to sham exposures. A nonmagnetite containing bacterial cell strain (CC-26) with similar genotype and phenotype to the magnetotactic bacteria was used as a control. These also showed no significant change in cell mortality between RF and sham exposed samples. Results indicate that the RF components of mobile phone exposure do not appear to be responsible for previous findings indicating cell mortality as a result of direct mobile phone exposure. A further mobile phone emission component that should be investigated is the 2-Hz magnetic field pulse generated by battery currents during periods of discontinuous transmission. View full abstract»

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  • Folding type specific secondary structure propensities of synonymous codons

    Page(s): 150 - 157
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (638 KB) |  | HTML iconHTML  

    We have proposed new amino acid secondary structure propensities in proteins with different folding types based on synonymous codons. They have been derived from 200 all alpha, all beta, alpha/beta, and alpha + beta proteins of known structures and their coding genes. The secondary structure propensities of the same codon in gene coding for different folding type proteins are not the same. For instance, amino acid Ile coded by AUU is indifferent to form the alpha unit in the alpha + beta protein class, but it is a former and a breaker for the alpha unit in the all alpha protein class and the alpha/beta class, respectively. On the other hand, the secondary structure propensities of different synonymous codons in the coding genes with the same folding type are also not all the same. As an example, CGU, CGG, and AGA, which are synonymous codons of Arg, are preferential to form the alpha unit in all alpha proteins, while CGA is an alpha unit breaker and the other two synonymous codons, CGC and AGG, are indifferent to form or break the alpha unit. As a result, protein secondary structure information contained both in mRNA sequences and in amino acid sequences has been introduced in these codon-based amino acid secondary structure propensities. These codon-based amino acid secondary structure propensities are helpful to in vitro protein design and protein secondary structure prediction. View full abstract»

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  • Effect of environmental fluctuations on the dynamic composition of engineered cartilage: a deterministic model in stochastic environment

    Page(s): 158 - 162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB) |  | HTML iconHTML  

    Dynamics of extracellular matrix (ECM) deposition and scaffold degradation in cell-polymer constructs have been studied in a random fluctuating environment created due to the applications of growth factors into the in vitro generation of cartilaginous constructs. Existing models of cell-polymer constructs for the design of engineered cartilage have been discussed and then a new deterministic scheme in random environment proposed taking into account the effects of growth factors as the environmental variability in the form of Gaussian white noise. Steady-state probability distribution of each individual component of the ECM in its homeostasis is found explicitly. The computer-simulated results of the model have been discussed and then compared with the data from a variety of scaffold systems and culture conditions. View full abstract»

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  • Algorithm to model gene expression on Affymetrix chips without the use of MM cells

    Page(s): 163 - 170
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (711 KB) |  | HTML iconHTML  

    DNA microarrays are powerful tools for quantifying gene expression patterns. However, obtaining reliable estimates of gene expression from raw measurements on microarrays presents several problems due to background contributions, nonspecific probe response, possible variation in probe sensitivities, and possible nonlinear responses of the probes to transcript concentration. In an effort to address the nonspecific response of probes, Affymetrix GeneChip arrays use two probes for each measurement. One of these probes, the mismatch (MM) probe, is intended to reflect the nonspecific response of the corresponding perfect match (PM) probe. However, the reliability of this approach has not been established by published experiments. Indeed, some research has shown that at high transcript concentrations, the nonspecific component of the PM signal is a negligible part of the MM signal. Five variations of a method to model and estimate levels of gene expression on Affymetrix chips, without the use of MM cells, are presented. To test the validity of the algorithms, six different concentrations of human liver cRNA were prepared. Each of these solutions was then hybridized on five Affymetrix hg95A arrays using five different scanners. The expression estimates obtained using each of the five algorithms bore a strong linear relationship to the cRNA concentrations, particularly at low cRNA concentrations. The five variations were applied to a Latin square data set and the results compared with those obtained using Affymetrix MAS 5.0 and using robust multichip analysis. R2 values obtained using the new techniques were comparable, while fold changes were superior. View full abstract»

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Aims & Scope

The IEEE Transactions on NanoBioscience publishes basic and applied papers dealing both with engineering, physics, chemistry, modeling and computer science and with biology and medicine with respect to molecules, cells, tissues. The content of acceptable papers ranges from practical/clinical/environmental applications to formalized mathematical theory.

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Meet Our Editors

Editor-in-Chief
Henry Hess
Department of Biomedical Engineering
Columbia University