Plasmonic refractive index sensitivity of tetrapod gold nanostars: tuning the branch length and protein layerLin-yu Lu, Jian Zhu, Guo-jun Weng, Jian-Jun Li and Jun-Wu ZhaoEur. Phys. J. D, 76 3 (2022) 54DOI: https://doi.org/10.1140/epjd/s10053-022-00375-w