Heterogeneous and anomalous diffusion inside lipid tubules

    Authors

    L. Guo; P. Chowdhury; J. Y. Fang;F. Gai

    Comments

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    Abbreviated Journal Title

    J. Phys. Chem. B

    Keywords

    FLUORESCENCE CORRELATION SPECTROSCOPY; PHOTOBLEACHING RECOVERY; CONTROLLED-RELEASE; LATERAL DIFFUSION; ORDERED ARRAYS; FABRICATION; NANOTUBES; MOLECULES; BINDING; MICROSTRUCTURES; Chemistry, Physical

    Abstract

    Self-assembled lipid tubules with crystalline bilayer walls are promising candidates for controlled drug delivery vehicles on the basis of their ability to release preloaded biological molecules in a sustained manner. While a previous study has shown that the release rate of protein molecules from lipid tubules depends on the associated molecular mass, suggesting that the pertinent diffusion follows the well-known Stokes-Einstein relationship, only a few attempts have been made toward investigating the details of molecular diffusion in the tubule interior. Herein, we have characterized the diffusion rates of several molecules encapsulated in lipid tubules formed by 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC8,9PC) using the techniques of fluorescence recovery after photobleaching (FRAP) and fluorescence correlation spectroscopy (FCS). Our results show that the mobility of these molecules depends not only on their positions in the DC8,9PC tubules but also on their respective concentrations. While the former indicates that the interior of the DC8,9PC tubules is heterogeneous in terms of diffusion, the latter further highlights the possibility of engineering specific conditions for achieving sustained release of a "drug molecule" over a targeted period of time. In addition, our FCS results indicate that the molecular diffusions inside the crystalline bilayer walls of the DC8,9PC tubules strongly deviate from the normal, stochastic processes, with features characterizing not only anomalous subdiffusions but also motions that are superdiffusive in nature.

    Journal Title

    Journal of Physical Chemistry B

    Volume

    111

    Issue/Number

    51

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    14244

    Last Page

    14249

    WOS Identifier

    WOS:000251792500025

    ISSN

    1520-6106

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