Biodegradable and Biocompatible P_DLLA-PEG_1k-P_DLLA Diacrylate Macromers: Synthesis, Characterisation and Preparation of Soluble Hyperbranched Polymers and Crosslinked Hydrogels

A series of P_DLLA-PEG_1k-P_DLLA tri-block co-polymers with various compositions, i.e., containing 2–10 lactoyl units, were prepared via ring opening polymerisation of d,l-lactide in the presence of poly (ethylene glycol) (PEG) (M_n = 1000 g·mol⁻¹) as the initiator and stannous 2-ethylhexanoate as the catalyst at different feed ratios. P_DLLA-PEG_1k-P_DLLA co-polymers were then functionalised with acrylate groups using acryloyl chloride under various reaction conditions. The diacrylated P_DLLA-PEG_1k-P_DLLA (diacryl-P_DLLA-PEG_1k-P_DLLA) were further polymerised to synthesize soluble hyperbranched polymers by either homo-polymerisation or co-polymerisation with poly(ethylene glycol) methyl ether methylacrylate (PEGMEMA) via free radical polymerisation. The polymer samples obtained were characterised by ¹H NMR (proton Nuclear Magnetic Resonance), FTIR (Fourier Transform Infra-red spectroscopy), and GPC (Gel Permeation Chromatography). Moreover, the diacryl-P_DLLA-PEG_1k-P_DLLA macromers were used for the preparation of biodegradable crosslinked hydrogels through the Michael addition reaction and radical photo-polymerisation with or without poly(ethylene glycol) methyl ether methylacrylate (PEGMEMA, M_n = 475 g·mol⁻¹) as the co-monomer. It was found that fine tuning of the diacryl-P_DLLA-PEG_1k-P_DLLA constituents and its combination with co-monomers resulted in hydrogels with tailored swelling properties. It is envisioned that soluble hyperbranched polymers and crosslinked hydrogels prepared from diacryl-P_DLLA-PEG_1k-P_DLLA macromers can have promising applications in the fields of nano-medicines and regenerative medicines. View Full-Text