Biodegradable and biocompatible supramolecular polymers based on poly(ε-caprolactone-co-δ-valerolactone)-b-poly(lactide) block copolymers with different branched structures: Synthesis, crystallization and properties

A novel biodegradable supramolecular polymer (SMP) was successfully synthesized via self-complementary quadruple hydrogen bonding-driven poly(ε-caprolactone-co-δ-valerolactone)-b-poly(lactide) (PCVL-b-PLA) block copolymers. The SMP structure was analyzed by ¹H NMR, GPC and the gel content, and found that the formation of self-complementary quadruple hydrogen bonds between UPy dimers not only expanded the polymer molecular chain, but also formed a cross-linked network structure for three-arm or four-arm branched PCVL-b-PLLA block copolymers. The results of WAXD and DSC indicated that compared with the precursor, the crystallization ability of supramolecular polymer was suppressed, but the stereocomplexation was conducive to the SMP crystallization. The tensile strength, elongation at break and tensile modulus were highly tunable and range from 7.1 ∼ 25.3 MPa, 588 ∼ 1860 % and 9.1 ∼ 21.4 MPa, respectively. The branching structure and sterecomplexation significantly adjusted the hydrophilicity and degradation of SMP. In addition, the synthesized SMP were evaluated for their biocompatibility by performing MTT assay using mouse fibroblasts (L929), indicating their high biocompatibility. The development of biodegradable and biocompatible supramolecular polymers may offer a new choice for tissue regeneration application.