Polymer–lipid microbubbles for biosensing and the formation of porous structures

Polymer–lipid microbubbles (PLBs) are generated by microfluidic flow-focusing devices to form a new class of long-lasting hybrid particles. The specific PLB construct developed is an elastic gas-filled microsphere with a polydimethylsiloxane (PDMS) shell containing phospholipids conjugated to functionalized polyethyleneglycol (PEG). Digital “droplet-based” microfluidics technology enables control of particle composition, size, and polydispersity (σ < 10%). Use of PDMS as a shell component improves the functionality and stability (lifetime > 6 months) of the hybrid particles due to the thermally maneuverable solidification process. With a gas core, they serve as a template material for creating three-dimensional porous structures and surfaces, requiring no cumbersome post-processing removal steps. By adding biotinylated PEG–lipid derivatives that offer targeting capabilities, we demonstrate the immobilization of fluorescent IgG antibodies on stationary PDMS–lipid microbubbles through biotin–avidin interactions and on-chip trapping for immunoassays. A PDMS–lipid composition offers several advantages such as biocompatibility and biodegradability for future in vivo use as porous engineered scaffolds, packing materials, or delivery (e.g. therapeutic) agents with cell targeting capability.

Long-lasting polymer–lipid microbubbles are suitable for biosensing and the production of three-dimensional porous structures and surfaces. Droplet microfluidics technology is used for control of particle composition, size, and polydispersity.Figure optionsDownload high-quality image (54 K)Download as PowerPoint slide