Surface modification of polylactic acid and poly (D, L-lactide-co-glycolide) biodegradable materials via chitosan-coating treatment: A new approach for developing novel antibacterial acupoint catgut embedding materials

Surgical site infections are liable to cause significant postoperative morbidity and increase health costs. However, polylactic acid and poly (D,L-lactide-co-glycolide) acupoint catgut-embedding therapy materials used to stimulate certain points for curing diseases are typically devoid of antibacterial activity. Here we report novel polylactic acid and poly (D,L-lactide-co-glycolide) embedding materials with effective antibacterial properties via chitosan-coating treatment that retained their inherent excellent characteristics. To achieve more comprehensive properties, polylactic acid polymer chips and poly (D,L-lactide-co-glycolide) multifilaments were adopted to fabricate embedding materials, and their preparation processes were studied. Meanwhile, a new one-dip-one-rolling coating system was designed and established in this work. Afterwards, characterizations such as fundamental properties, mechanical properties and biocompatibility were explored. The results showed that both the polylactic acid and poly (D,L-lactide-co-glycolide) groups with covered chitosan layers showed a different increase in weight and diameter. FT-IR analysis indicated that there were interactions between the pure embedding materials and chitosan molecules, the present of hydroxyl group (-OH) and some polar bonds such as (N-H) amide II and (C=O) amide I would be benefit for the hydrophilicity of modified materials. Chitosan-coated polylactic acid monofilaments in group 2 (breaking strength = 31.26 ± 1.62 cN/dtex, breaking elongation = 34.82 ± 5.21%) and chitosan-coated poly (D,L-lactide-co-glycolide) braiding threads in group 2 (breaking strength = 92.58 ± 1.69 cN/dtex, breaking elongation = 73.39 ± 2.38%) showed better mechanical properties. Antibacterial efficacy and cell cytocompatibility of polylactic acid and poly (D,L-lactide-co-glycolide) groups were greatly enhanced after coating. The degradation behaviors were slowed down, providing a longer-lasting effect during the treatment process. In conclusion, the modified polylactic acid and poly (D,L-lactide-co-glycolide) embedding materials with good, comprehensive performance presented great potential in acupoint catgut-embedding therapy clinical applications.