Dimethyloxalylglycine improves angiogenesis of ZIF-8-coated implant

Nanoscale zeolitic imidazolate framework-8 coating with certain density can significantly improve the osteogenic activity of titanium implants both in vitro and in vivo. In this study, we loaded dimethyloxalylglycine into zeolitic imidazolate framework-8-modified implants (Z-AHT) to enhance the angiogenic activity, and the obtained products were denoted as D-AHT. Firstly, we characterized the specimens via scanning electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, and surface contact angle. Then, the release kinetics of both zinc ions and dimethyloxalylglycine were investigated. To illustrate the combined effects of surface topography and chemistry (zeolitic imidazolate framework-8 and dimethyloxalylglycine) on osteogenic and angiogenic activity, MC3T3-E1 preosteoblast cells and human umbilical vein endothelial cells were respectively cultured on D-AHT. Pure Ti and Z-AHT were designated as control groups. As evidenced by the expression of osteogenic genes (Alp, Col1, Opg, and Runx2) and the secretion of ALP protein, D-AHT showed comparable osteogenic activity to Z-AHT which was better than that of Ti. Further angiogenesis assay revealed a better human umbilical vein endothelial cell migration on D-AHT, suggesting that D-AHT can be an attractive candidate for application in implant surface modification.