RETRACTION: Mechanical, microstructural properties and cell adhesion of Sr/Se-hydroxyapatite/ graphene/polycaprolactone nanofibers (Vol 34, pg 536, 2021) (Retraction of Vol 34, Pg 536, 2021)

Electrospun nanofibrous scaffolds containing co-dopant of Sr/Se into carbonated hydroxyapatite has been synthesized in situ with graphene (G) nanosheets and carried on polycaprolactone at different contributions of G. The powder and the nanofibrous samples were investigated using X-ray diffraction, transmission electron microscopy, and field emission scanning electron microscopy (FESEM). The FESEM micrographs show that the highest content of G (0.2 G) was formed in non-oriented/rough/cracked fibers with diameters around 0.3-0.4 mu m at the maximum. The tensile strength of nanofibrous scaffolds was improved with the addition of G nanosheets and the maximum tensile strength of 0.2 G was around 6.39 +/- 0.24 MPa, while the minimum cell viability ratio was about 94.4 +/- 3.2% for the free G nanofibers. The in vitro attachment of HFB4 cell lines was investigated and it showed that nanofibrous scaffolds have induced cells to be proliferated and spread on the nanofibrous scaffolds' surface. This behavior of cells growth encourages more investigations for these nanofibrous scaffolds to be promoted for clinical applications.