Ultrasound protein-copolymer microbubble library engineering through poly(vinylpyrrolidone-co-acrylic acid) structure

Area of Science:

• Biomaterials Science
• Ultrasound Imaging
• Nanotechnology

Background:

• Albumin-coated microbubbles are standard ultrasound contrast agents.
• Their limited contrast enhancement duration restricts clinical utility.
• Protein-copolymer hybrids can improve microbubble performance.

Purpose of the Study:

• To investigate how copolymer structural properties influence bovine serum albumin (BSA)-coated microbubble characteristics.
• To understand the impact of copolymer structure on micelle formation, protein-copolymer hybrids, and microbubble shell properties.
• To optimize BSA@P(VP-AA) microbubbles for enhanced ultrasound contrast.

Main Methods:

• Synthesized BSA@P(VP-AA) microbubbles using copolymers with varying -C8H17 and -C18H37 end groups and molecular weights (3.5–15 kDa).
• Evaluated microbubble production and performance across 60 formulations.
• Utilized simulation and experimental data to analyze BSA-copolymer interactions.

Main Results:

• Microbubbles with -C8H17 terminated copolymers showed up to 200-fold higher concentration and 7-fold greater acoustic response.
• Ultrasound contrast enhancement duration increased fivefold compared to plain BSA microbubbles.
• Enhanced acoustic performance was maintained during in vivo cardiac ultrasound imaging without increased liver accumulation.

Conclusions:

• Copolymer structure, specifically terminal end group and molecular weight, critically affects microbubble formation and performance.
• Optimized protein-copolymer-coated microbubbles offer significantly improved ultrasound contrast and duration.
• These findings provide valuable insights for designing advanced ultrasound contrast agents.