Proangiogenic effect and underlying mechanism of holmium oxide nanoparticles: a new biomaterial for tissue engineering oleh Yuxiao Luo, Yifan Zheng, Ziwei Chen, Minhua Mo, Jiling Xie, Xiaohe Zhou, Yupeng Wu, Qiyuan Yang, Manjia Zheng, Xiaowen Hu, Liangjiao Chen, Zedong Lan