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 (beta-amino ester) (P beta AE) polymers. P beta AE was prepared with four different diacrylate/diamine monomers including; 1.1:1 (P beta AE1), 1.5:1 (P beta AE1.5), 2:1 (P beta AE2), and 3:1 (P beta AE3), which was UV cross-linked using dimethoxy phenyl-acetophenone agent. These P beta AE were then used for preparation of Poly-L-ArgMA/P ss AE 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/P beta AE1.5 sample. Also, the controllable degradation rate and different mechanical properties were obtained, depending on the P beta AE monomer ratio. Noticeably, the tensile strength of the P beta AE 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/P beta AE samples significantly improved L929 cell viability, attachment and proliferation. Poly-L-ArgMA also enhanced the antibacterial activities of P beta AE against both Escherichia coli (similar to 5.1 times) and Staphylococcus aureus (similar to 2.7 times). In summary, the antibacterial and pH-sensitive Poly-L-ArgMA/P beta AE1.5 with suitable mechanical, degradation and biological properties could be an appropriate candidate for soft tissue engineering, specifically wound healing applications.

Automated summary

During the study, a biodegradable pH-sensitive and antibacterial hydrogel was synthesized for soft tissue engineering. The Poly-L-ArgMA/P beta AE1.5 sample showed a 1.5-fold increase in swelling ratio under acidic conditions. In addition, different mechanical properties and controllable degradation rate were achieved based on the ratio of P beta AE monomers. The Poly-L-ArgMA/P beta AE1.5 sample also exhibited enhanced antibacterial activities against Escherichia coli and Staphylococcus aureus.