Fluorescently labeled degradable thermoplastic polyurethane elastomers: Visual evaluation for the degradation behavior

Abstract

Thermoplastic polyurethane elastomers (TPU) were synthesized with isophorone diisocyanate (IPDI) as the rigid segment, poly(lactic-co-glycolic acid) (PLGA-PEG-PLGA) diol as soft segment, and 1,4-butanediol (BDO) as the chain extender. During the chain extension process, three kinds of fluorescent monomers 4-(2-hydroxyethylamino)21,8-naphthoyl-(2-hydroxyethyl)imide (HNHI), 1,5-dihydroxy naphthalene (DHN), and dicoumarin (DIC) were introduced to get the fluorescently labeled degradable TPUs. The structure and degradation properties of the TPUs were characterized in detail. The results showed that there was no significant effect found on average molecular weight, mechanical properties, and glass transition temperature of polyurethane by introducing 0.001% (wt) weight percent of fluorescence monomers. The degradation behavior of fluorescent-tagged thermoplastic elastomer has been characterized with fluorescence microscopy. Results showed that polyurethane elastomers, in which fluorescence monomers especially HNHI were introduced by chemical reaction, had more homogeneous and stable fluorescence intensity than that with fluorescence monomers introduced by post blending. This work also provides a promising visual characterization approach to monitor degradation behavior of degradable TPUs for tissue engineering applications or drug delivery system.

Fluorescent, online monitoring of PLGA degradation for regenerative medicine applications

“…Recent advances in the area have utilised non-invasive, uorescent techniques to tag biomaterials and assess degradation through subsequent changes in uorescence. 7 These uorescent tagging approaches have been utilised on several biomaterials to date, including chitosan, 8 PEG-dextran, 7 collagen, 7 brin 9 and thermoplastic polyurethane elastomers, 10 with correlations being observed between changes in uorescence intensity and weight loss during degradation, both in vitro and in vivo. Nondestructive assessment of degradation decreases the reliance on end-point analysis and allows for continued sample monitoring both in vitro and in vivo.…”

Biodegradable Polyurethane Scaffolds in Regeneration Therapy: Characterization and In Vivo Real-Time Degradation Monitoring by Grafted Fluorescent Tracer

“…The slower fluorescence decay rate of the PU-5 device makes it superior to the PLGA-gold scaffold in terms of the preclinical experimental studies. For the chemically grafted fluorescent molecules, Liu and his coauthors prepared three PU-based elastomers with chemically grafted fluorescent molecules . However, the rapid decay of the fluorescence response and the lack of biocompatibility evaluation and in vivo imaging validation severely limit their potential as in vivo real-time monitoring devices.…”

“…For the chemically grafted fluorescent molecules, Liu and his coauthors prepared three PU-based elastomers with chemically grafted fluorescent molecules. 67 However, the rapid decay of the fluorescence response and the lack of biocompatibility evaluation and in vivo imaging validation severely limit their potential as in vivo real-time monitoring devices. Zhang and his coauthors prepared porous PCL scaffolds grafted with a fluorescent molecule (SY-1030 dye), which could be clearly imaged initially after implantation into the subcutaneous tissues of the back of mice.…”

Synthesis and characterization of fluorescein-grafted polyurethane for potential application in biomedical tracing

“…This also provides a feasible way to trace the degradation behavior of a biodegradable polymer. 24 Unfortunately, the conjugated amount of calcein cannot be calculated directly because the amount of calcein in grafted-polyurethane is too small (the molar ratio of calcein to soft segment was 0.1% or 0.5%), which is out of the measurement range of NMR and XPS. Moreover, no fluorescence decay has been detected in solution after grafted samples soaking in deionized water for 48 h. So, we postulated all calcein has been linked in the polymer chain.…”