3D printed PCLA scaffold with nano-hydroxyapatite coating doped green tea EGCG promotes bone growth and inhibits multidrug-resistant bacteria colonization.

OBJECTIVES: 3D-printing scaffold with specifically customized and biomimetic structures gained significant recent attention in tissue engineering for the regeneration of damaged bone tissues. However, constructed scaffolds that simultaneously promote bone regeneration and in situ inhibit bacterial proliferation remains a great challenge. This study aimed to design a bone repair scaffold with in situ antibacterial functions. MATERIALS AND METHODS: Herein, a general strategy is developed by using epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, firmly anchored in the nano-hydroxyapatite (HA) and coating the 3D printed polymerization of caprolactone and lactide (PCLA) scaffold. Then, we evaluated the stability, mechanical properties, water absorption, biocompatibility, and in vitro antibacterial and osteocyte inductive ability of the scaffolds. RESULTS: The coated scaffold exhibit excellent activity in simultaneously stimulating osteogenic differentiation and in situ resisting methicillin-resistant Staphylococcus aureus colonization in a bone repair environment without antibiotics. Meanwhile, the prepared 3D scaffold has certain mechanical properties (39.3 ± 3.2 MPa), and the applied coating provides the scaffold with remarkable cell adhesion and osteogenic conductivity. CONCLUSION: This study demonstrates that EGCG self-assembled HA coating on PCLA surface could effectively enhance the scaffold's water absorption, osteogenic induction, and antibacterial properties in situ. It provides a new strategy to construct superior performance 3D printed scaffold to promote bone tissue regeneration and combat postoperative infection in situ.

[Effects of astragalus polysaccharides-chitosan/polylactic acid composite material on biological behavior of canine bone marrow stromal cells cultured in vitro].

OBJECTIVE: To observe the biological behavior of canine bone marrow stromal cells (BMSCs) cultured in vitro with the astragalus polysaccharides-chitosan/polylactic acid (AP-C/PLA) and with the chitosan/polylactic acid (C/PLA) and to find a suitable compound material for periodontal tissue engineering. METHODS: BMSCs (induced 14 days by 50 mg/L vitamine C, 10(-8) mol/L dexamethasone, 10 mmol/L beta-sodium glycerylphosphate) were cultured on AP-C/PLA or C/PLA for 5 days respectively. The BMSCs attachment and the morphology were observed with scanning electronic microscope and the combining rates were counted. Type I collagen synthesis was examined with immunohistochemistry staining and the content of osteocalin was determined with radio-immunological method. RESULTS: Combining rates, type I collagen synthesis, and the content of osteocalin of BMSCs on AP-C/PLA were significantly higher than those on C/PLA. CONCLUSION: AP-C/PLA may promote the BMSC proliferation, differentiation and extracellular matrix synthesis, and it can be used as a good scaffold material for bone tissue engineering.