Biotinylated Microbubbles Targeted to Amyloid

Abstract

Background: Ultrasonography uses microbubbles for enhanced imaging. We created microbubbles that have preferential adherence to amyloid protein by utilizing the affinity of serum amyloid component P (SAP) to amyloid along with avidin-biotin interactions. Methods: Biotin-labeled albumin was incorporated into the albumin shell of fluorocarbon gas-filled bubbles. The bubble was attached through a bridge with biotin incorporated into the shell of the bubble and incubated with avidin-labeled SAP which was pre-bound to SA ("synthetic amyloid"). This resulted in a bubble targeted to amyloid. The bubbles were evalu- ated using fluorescent microscopy and fluorescence-activated cell sorting (FACS). Results: Microbubbles with a protein shell were bound to amyloid by utilizing the affinity of SAP for amyloid and biotin- avidin interactions. Conclusion: We introduce microbubbles specifically targeted to amyloid deposits and intended as future mediators of ul- trasound detection of amyloid deposits and amyloid-selective drug delivery.