Probing microbubble targeting with atomic force microscopy.

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Cell Biology

Background:

• Microbubble applications are expanding into biological targeting and drug/gene delivery.
• Accurate assessment of molecular targeting efficacy and strength is crucial for these new applications.

Purpose of the Study:

• To evaluate the feasibility of using Atomic Force Microscopy (AFM) to measure the adhesion forces of targeted microbubbles.
• To quantify the interaction strength between targeted microbubbles and specific cell surface antigens.

Main Methods:

• Targeted microbubbles were engineered using biotin-avidin chemistry and a CD31 antibody.
• These microbubbles were used to probe Sk-Hep1 hepatic endothelial cell cultures.
• Atomic Force Microscopy (AFM) was employed to measure single microbubble-cell adhesion forces with piconewton resolution.

Main Results:

• A single distribution of adhesion forces was observed, with a median force of 93pN.
• This interaction force was attributed to the unbinding event between the CD31 antibody and its antigen.
• Data on the distances between interaction forces were also acquired.

Conclusions:

• Atomic Force Microscopy (AFM) is a capable technique for measuring single microbubble-cell interactions.
• The study demonstrates the feasibility of targeted microbubbles for specific cell line targeting.
• Findings provide insights for future microbubble design and fabrication.