Development of X-ray opaque poly(lactic acid) end-capped by triiodobenzoic acid towards non-invasive micro-CT imaging biodegradable embolic microspheres

• Published in: European polymer journal 2018-11, Vol.108, p.337-347
• Main Authors: Wang, Wenhuan, Wei, Zhiyong, Sang, Lin, Wang, Yongxuan, Zhang, Jie, Bian, Yufei, Li, Yang
• Format: Article
• Language: English
• Subjects: Aluminum; Attenuation; Biodegradability; Biodegradable materials; Capping; Computed tomography; Degradation; Degradation behavior; Iodine; Materials traceability; Medical imaging; Micro-CT imaging; Microspheres; NMR; Nuclear magnetic resonance; Poly(lactic acid) microspheres; Polylactic acid; Radiopacity; Radiopaque; Stability; Toxicity; X-rays
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2018.09.018

[Display omitted] •End-group modification of poly(lactic acid) towards X-ray opaque materials.•Poly(lactic acid) was end-capped with triiodobenzoic acid.•Non-invasive micro-CT imaging biodegradable embolic microspheres were developed.•In vitro degradation behavior of X-ray opaque microspheres was traced. Non-invasive micro-CT imaging functionalized biodegradable polymeric microspheres for interventional embolization are gaining increasing attention recent years. We herein report a facile method of end-group modification to prepare X-ray opaque poly(lactic acid) (PLA) using triiodobenzoic acid (TIBA) as end-capping agent, and develop the inherently radiopaque poly(lactic acid) materials towards embolic microspheres traceable with non-invasive micro-CT imaging. Two types, that is, linear 2-arm and star 4-arm, of TIBA terminated PLA were designed and successfully synthesized by 1H NMR characterization. Then these PLA materials were used to fabricate polymeric microspheres with well-controlled size (100–200 μm) by W/O emulsification method. As expected, the star 4-arm TIBA terminated poly(lactic acid) (I-S-PLA) microspheres possessed higher iodine content and exhibited greater radiopacity compared with linear 2-arm analogue (I-L-PLA). Both these microspheres showed low cytotoxicity and controllable micro-CT imaging. Furthermore, the effects of linear and star structure of I-PLA microspheres on in vitro degradation behavior was investigated by GPC, micro-CT, SEM and EDS. The degradable results revealed that iodine content of I-L-PLA decreased faster than that of I-S-PLA, which resulted in a further attenuation in micro-CT imaging. Consequently, CT-imaging of I-S-PLA microspheres did not drop sharply over degradation period, exhibiting higher HU values than aluminum wedge of 2 mm. These findings suggested that the biodegradable radiopaque poly(lactic acid) microspheres could be traceable by non-invasive micro-CT imaging, which are promising embolic agents.