Antibacterial and pH-sensitive methacrylate poly-L-Arginine/poly (β-amino ester) polymer for soft tissue engineering.

During the last decade, pH-sensitive biomaterials containing antibacterial agents have grown exponentially in soft tissue engineering. The aim of this study is to synthesize a biodegradable pH sensitive and antibacterial hydrogel with adjustable mechanical and physical properties for soft tissue engineering. This biodegradable copolymer hydrogel was made of Poly-L-Arginine methacrylate (Poly-L-ArgMA) and different poly (β- amino ester) (PβAE) polymers. PβAE was prepared with four different diacrylate/diamine monomers including; 1.1:1 (PβAE1), 1.5:1 (PβAE1.5), 2:1 (PβAE2), and 3:1 (PβAE3), which was UV cross-linked using dimethoxy phenyl-acetophenone agent. These PβAE were then used for preparation of Poly-L-ArgMA/PβAE polymers and revealed a tunable swelling ratio, depending on the pH conditions. Noticeably, the swelling ratio increased by 1.5 times when the pH decreased from 7.4 to 5.6 in the Poly-L-ArgMA/PβAE1.5 sample. Also, the controllable degradation rate and different mechanical properties were obtained, depending on the PβAE monomer ratio. Noticeably, the tensile strength of the PβAE hydrogel increased from 0.10 ± 0.04 MPa to 2.42 ± 0.3 MPa, when the acrylate/diamine monomer molar ratio increased from 1.1:1 to 3:1. In addition, Poly-L-ArgMA/PβAE samples significantly improved L929 cell viability, attachment and proliferation. Poly-L-ArgMA also enhanced the antibacterial activities of PβAE against both Escherichia coli (~5.1 times) and Staphylococcus aureus (~2.7 times). In summary, the antibacterial and pH-sensitive Poly-L-ArgMA/PβAE1.5 with suitable mechanical, degradation and biological properties could be an appropriate candidate for soft tissue engineering, specifically wound healing applications.