Direct force measurements between siRNA and chitosan molecules using force spectroscopy

Sailong Xu, Mingdong Dong, Xiudong Liu, Kenneth A Howard, Jørgen Kjems, Flemming Besenbacher

    Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

    Abstract

    Information on the interaction strength between small interfering RNA (siRNA) and chitosan can contribute to the understanding of the formation and stability of chitosan/siRNA nanoparticles used as siRNA delivery systems for gene silencing. In this study, we utilize atomic force microscopy to obtain force spectroscopy results of the interaction strengths between siRNA and chitosan measured in physiological phosphate buffered saline buffer at different pH. The force measurements revealed that the adhesive interactions decreased in force strength and force frequency as the pH was increased from 4.1 to 6.1, 7.4, and 9.5, exhibiting distinct multimodal distributions of the interaction forces between siRNA and chitosan molecules at acidic pH and only negligible adhesive forces were observed at neutral or high pH. The strong pH dependence of siRNA-chitosan interactions can provide a convincing rationale for siRNA/chitosan complex formation and nanoparticle stability under low acidic conditions. These findings demonstrate that the use of force spectroscopy for the adhesive force measurements allows an evaluation of the complexing ability between siRNA and chitosan that can be utilized to predict nanoparticle stability.
    Original languageEnglish
    JournalBiophysical Journal
    Volume93
    Issue3
    Pages (from-to)952-9
    Number of pages7
    ISSN0006-3495
    DOIs
    Publication statusPublished - 2007

    Keywords

    • Chitosan
    • Chromatography, High Pressure Liquid
    • Drug Stability
    • Gold
    • Green Fluorescent Proteins
    • Hydrogen-Ion Concentration
    • Microscopy, Atomic Force
    • Models, Molecular
    • RNA, Small Interfering
    • Surface Properties

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