Force spectroscopy of streptavidin conjugated lipid coated microbubbles

Abstract

AbstractForce microscopy has been used to investigate the mechanical properties of phospholipid coated microbubbles and to quantify their stiffness. The mechanical properties were investigated using tipless cantilevers to compress microbubbles attached to a gold surface under aqueous conditions. The phospholipid microbubbles were produced by microfluidic flow focusing and were found to have stiffness of 25 mN m–1. The attachment of a streptavidin coating increased the microbubble stiffness by a factor of 30 to ∼750 mN m–1. Further, estimation of the frequency response based on values of stiffness obtained by force spectroscopy seems reasonable in comparison with those of an uncoated bubble and a polyethylene glycol coated Bracco SonoVue BR14 bubble, suggesting that the present approach may provide useful information for the development of novel microbubble coatings.