Preparation and properties of bio-based degradable fluorescent polyesters

A series of bio-based degradable fluorescent polyesters (BBPP-Cys and BBPP-Ser) were synthesized from natural bio-based materials such as castor oil (CO), citric acid (CA) and L-cysteine (L-cys) or L-serine (L-ser). The structure and fluorescence characteristics were characterized by FTIR, 1HNMR, UV-Vis spectra and fluorescence spectra. At the same time, the water contact angle, particle size, mechanical properties, degradation properties and cytotoxicity of the polyesters were measured. The results showed that the unique six-membered ring structure suspended on the polyesters backbone were responsible for their fluorescent properties. BBPP-Cys samples had the strongest UV absorption at 265 nm, and their fluorescence emission signal was the strongest at 445 nm. For BBPP-Ser samples, their strongest UV absorption and fluorescence emission were at 266 nm and at 460 nm, respectively. The synthesized polyesters had good hydrophilicity and small particle size, the tensile strength ranged from 1.21 MPa to 1.95 MPa. The degradation rate of the samples in 0.1 mol/L NaOH solution reached over 60% in 7 days. The cytotoxicity of fluorescent polyesters was tested by MTT assay. The results demonstrated that the cell viability of the synthesized fluorescent polyesters was all greater than 90%, indicating that they had good biocompatibility. © 2020, Editorial Office of FINE CHEMICALS. All right reserved.