Novel Copolyanhydrides Combining Strong Inherent Fluorescence and a Wide Range of Biodegradability: Synthesis, Characterization and in vitro Degradation

Abstract

In this work, a novel diacid monomer was synthesized in a very convenient scheme. The monomer is derived from naturally occurring products and emits strong fluorescence when polymerized to polyanhydride. The chemical structure of the monomer dCPS is as follows: HOC(O)ArOC(O)(CH2)2C(O)O--Ar--COOH. Copolyanhydrides composed of dCPS and sebacic acid were further prepared by melt copolycondensation, and characterized by IR, NMR, UV-Vis, DSC and fluorometry. The emission wavelength (lambda(em)) of the copolymers could be tuned by the excitation wavelength (lambda(ex)). Fluorescence intensity increased with the increase of dCPS content. The microspheres fabricated from the copolymer with dCPS content as low as 10% could be clearly visualized with fluorescence microscopy. Either blue or green images of the microspheres could be captured with an excitation of UV and visible light. The degradation rate of the copolyanhydrides decreased as the dCPS fraction increased, and the degradation duration could be modulated from several days to more than three months. In addition, it was found that the copolyanhydrides displayed surface degradation characteristics. In view of the advantages of the novel copolyanhydrides, such as easy preparation, unique inherent luminescent properties, and widely adjustable degradation rate, they might be useful for biomedical engineering.

The effect of substitution levels on the luminescent and degradation properties of fluorescent poly(ester‐anhydride)s

“…em of P(dCPS:SA) was 410 nm with an excitation wave- length at 327 nm, and 476 and 510 nm at 462 nm. 16 The phenomenon of shift may be due to conjugation between methoxyl group and benzene ring, which reduces the energy level of the excited state. P(dMOCPS: SA) and P(ddMOCPS:SA) have almost same wavelength of fluorescence with a UV excitation.…”

“…The maximum emission wavelength varies with the excitation wavelength, 480 and 520 nm with the excitation wavelength at 470 and 430 nm at 356 nm. 16 But, the copolyanhydrides with dCPS content more than 50% could not be dissolved in common organic solvents, which limited their applications. To circumvent the shortcoming and find fluorescent polyanhydrides with new properties, we synthesized two diacids by the same method using 4-hydroxy-3-methoxybenzoic acid (vanillic acid) and 4-hydroxy-3,5-dimethoxybenzoic acid (syringic acid) as initial substances.…”

In vivo Degradation and Histocompatibility of a Novel Class of Fluorescent Copolyanhydrides, Poly{[di(p‐carboxyphenyl) succinate]‐co‐(sebacic anhydride)}

“…Monomers and polymers were synthesized according to the procedures reported previously 17. Briefly, p ‐Hydroxybenzoic acid was dissolved in a mixture of THF and pyridine, succinic chloride was added dropwise to the above solution with magnetic stirring under dry nitrogen atmosphere at room temperature.…”

“…In our previous work, we found a novel class of fluorescent poly(anhydride‐ester), poly[di( p ‐carboxyphenyl) succinate anhydride] [P(dCPS)] 17. The corresponding monomer was conveniently synthesized with a high yield by condensation of succinic chloride with p ‐hydrobenzoic acid.…”