Center for Photonic Science and Engineering, Skolkovo Institute of Science and Technology, Moscow 121205, Russia.
Department of Biomaterials, Dmitry Mendeleev University of Chemical Technology of Russia, Moscow 125047, Russia.
Biomater Adv. 2025 Jan;166:214074. doi: 10.1016/j.bioadv.2024.214074. Epub 2024 Oct 21.
While albumin-coated microbubbles are routine contrast agents for ultrasound imaging, their short duration of contrast enhancement limits their use, yet can be improved by incorporating protein-copolymer hybrids into microbubble shells. The incorporation of N-vinyl-2-pyrrolidone and acrylic acid copolymer (P(VP-AA)) has been shown to enhance the performance of bovine serum albumin (BSA)-coated microbubbles. However, the impact of the copolymer structural properties on key microbubble characteristics (i.e., concentration, mean diameter and acoustic response) remains poorly understood. Therefore, we hypothesize that the copolymer structure affects its capacity to form micelle-like nanoaggregates, protein-copolymer hybrids, and microbubble shells, ultimately influencing the physicochemical and acoustic properties of the microbubbles.
Here we evaluate the production and performance of BSA@P(VP-AA) microbubbles synthesized using a series of P(VP-AA) copolymers with -CH and -CH end groups and molecular weight cutoffs between 3.5 and 15 kDa. Both simulation and experimental data demonstrate that interactions between BSA and the copolymers significantly influence the performance of the resulting microbubbles across the library of 60 formulations.
The introduction of -CH terminated copolymers into microbubble shells resulted in up to 200-fold higher concentration, 7-fold greater acoustic response, and 5-fold longer ultrasound contrast enhancement compared to plain BSA microbubbles. The enhanced acoustic performance was sustained during in vivo cardiac ultrasound imaging, without altering liver accumulation after copolymer introduction. These findings underscore how optimizing copolymer structure (specifically the terminal end group and molecular weight) can tailor the formation and performance of protein-copolymer-coated microbubbles, offering valuable insights for designing ultrasound contrast agents.
虽然白蛋白包覆的微泡是超声成像的常规造影剂，但它们增强对比的持续时间有限，限制了其应用，但通过将蛋白-共聚物杂化物纳入微泡壳中可以改善这种情况。已证明，将 N-乙烯基-2-吡咯烷酮和丙烯酸共聚物（P(VP-AA)）纳入其中可以提高牛血清白蛋白（BSA）包覆微泡的性能。然而，共聚物结构特性对关键微泡特性（即浓度、平均直径和声学响应）的影响仍知之甚少。因此，我们假设共聚物结构会影响其形成胶束样纳米聚集体、蛋白-共聚物杂化物和微泡壳的能力，最终影响微泡的物理化学和声学性质。
在这里，我们评估了使用一系列具有-CH 和 -CH 端基和分子量截止值在 3.5 至 15 kDa 之间的 P(VP-AA)共聚物合成的 BSA@P(VP-AA)微泡的生产和性能。模拟和实验数据均表明，BSA 和共聚物之间的相互作用会显著影响整个 60 种配方的微泡的性能。
与普通 BSA 微泡相比，将-CH 端基共聚物引入微泡壳中可使浓度提高多达 200 倍，声学响应提高 7 倍，超声对比增强持续时间延长 5 倍。在体内心脏超声成像中，增强的声学性能得以维持，而在引入共聚物后，对肝脏的积累没有改变。这些发现强调了如何通过优化共聚物结构（特别是端基和分子量）来定制蛋白-共聚物包覆微泡的形成和性能，为设计超声造影剂提供了有价值的见解。
