Ogbonna Nduka D, Guragain Parikshit, Mayandi Venkatesh, Sadrinia Cyrus, Danrad Raman, Jois Seetharama, Lawrence Jimmy
Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Department of Pathological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
J Am Chem Soc. 2025 May 14;147(19):16171-16178. doi: 10.1021/jacs.5c00938. Epub 2025 May 1.
The development of metal-free magnetic resonance imaging (MRI) agents demands precise control over molecular architecture to achieve optimal performance. Current fluorine-based contrast agents rely on maximizing fluorine content (>20 wt %) for sensitivity, requiring extensive solubilizing groups that lead to signal-diminishing aggregation. Here we show that discrete brush polymers ( = 1.0) with precise backbone lengths and a single terminal fluorine group achieve superior imaging performance through architectural control rather than high fluorine content. This design prevents both intra- and intermolecular fluorine aggregation while maintaining high aqueous solubility, enabling sharper signals and higher sensitivity than conventional systems despite containing less than 7 wt % fluorine. Systematic investigation reveals how backbone length controls fluorine mobility and signal generation, establishing clear structure-property relationships previously obscured by molecular heterogeneity. This work demonstrates how precise architectural control can enhance functional performance beyond traditional approaches, providing new strategies for designing imaging materials.
无金属磁共振成像（MRI）造影剂的研发需要对分子结构进行精确控制，以实现最佳性能。当前基于氟的造影剂依靠最大化氟含量（>20 wt%）来提高灵敏度，这需要大量的增溶基团，而这些基团会导致信号减弱的聚集。在此，我们表明，具有精确主链长度和单个末端氟基团的离散刷状聚合物（ = 1.0）通过结构控制而非高氟含量实现了卓越的成像性能。这种设计既能防止分子内和分子间的氟聚集，又能保持高水溶性，尽管氟含量低于7 wt%，但与传统体系相比，仍能产生更清晰的信号和更高的灵敏度。系统研究揭示了主链长度如何控制氟的迁移率和信号产生，确立了此前因分子异质性而模糊不清的明确结构-性能关系。这项工作证明了精确的结构控制如何超越传统方法增强功能性能，为成像材料的设计提供了新策略。
