Biodegradable Polyurethane
Scaffolds in Regeneration
Therapy: Characterization and In Vivo Real-Time Degradation
Monitoring by Grafted Fluorescent Tracer
posted on 2023-12-19, 16:04authored byXiaoyu Lei, Boyuan Yang, Jie Chen, Fang Yang, Jiajing Tang, Jihua Li, Qing Zhao, Jinzheng Zhang, Jidong Li, Yubao Li, Yi Zuo
There is an urgent need to assess material degradation in situ and in real time for their promising application
in regeneration therapy. However, traditional monitoring methods in vitro cannot always profile the complicated behavior in vivo. This study designed and synthesized a new biodegradable
polyurethane (PU-P) scaffold with polycaprolactone glycol, isophorone
diisocyanate, and l-lysine ethyl ester dihydrochloride. To
monitor the degradation process of PU-P, calcein was introduced into
the backbone (PU-5) as a chromophore tracing in different sites of
the body and undegradable fluorescent scaffold (CPU-5) as the control
group. Both PU-P and PU-5 can be enzymatically degraded, and the degradation
products are molecularly small and biosafe. Meanwhile, by virtue of
calcein anchoring with urethane, polymer chains of PU-5 have maintained
the conformational stability and extended the system conjugation,
raising a structure-induced emission effect that successfully achieved
a significant enhancement in the fluorescence intensity better than
pristine calcein. Evidently, unlike the weak fluorescent response
of CPU-5, PU-5 and its degradation can be clearly imaged and monitored
in real time after implantation in the subcutaneous tissue of nude
mice. Meanwhile, the in situ osteogeneration has also been promoted
after the two degradable scaffolds have been implanted in the rabbit
femoral condyles and degraded with time. To sum up, the strategy of
underpinning tracers into degradable polymer chains provides a possible
and effective way for real-time monitoring of the degradation process
of implants in vivo.