Nature-derived epigallocatechin gallate/duck's feet collagen/hydroxyapatite composite sponges for enhanced bone tissue regeneration

Scaffolds mimicking structural and chemical characteristics of the native bone tissues are critical for bone tissue engineering. Herein, we have developed and characterized epigallocatechin gallate/duck's feet collagen/hydroxyapatite (EGCG/DC/HAp) composite sponges that enhanced the bone tissue regeneration. The three-dimensional composite sponges were synthesized by loading various amounts (i.e. 1, 5 and 10M) of EGCG to duck feet derived collagen followed by freeze-drying and then coating with hydroxyapatite. Several measuremental techniques were employed to examine the properties of the as-fabricated composite sponges including morphology and structure, porosity, compressive strength, etc. and as well compared with pristine duck feet derived collagen. SEM observations of EGCG/DC/HAp sponges showed the formation of a highly porous collagen matrix with EGCG embodiment. The porosity and pore size of sponges were found to increase by high EGCG content. The compressive strength was calculated as 3.54 +/- 0.04, 3.63 +/- 0.03, 3.89 +/- 0.05, 4.047 +/- 0.05MPa for 1, 5 and 10M EGCG/DC/HAp sponges, respectively. Osteoblast-like cell (BMSCs isolated from rabbit) culture and in vivo experiments with EGCG/DC/HAp sponges implanted in nude mouse followed by histological staining showed enhanced cell internalization and attachment, cell proliferation, alkaline phosphatase expressions, indicating that EGCG/DC/HAp sponges have ahigh biocompatibility. Moreover, highEGCG content in the EGCG/DC/HAp sponges have led to increased cellular behavior. Collectively, the 5M of EGCG/DC/HAp sponges were suggested as the potential candidates for bone tissue regeneration.