In our study, the graphene were first treated with aminopropyl-trimethoxysilane before it was modified with an antibody. Attachment of the antibody ws done using EDC/NHS chemistry.
Please see the paper Israa Al-Ogaidi, Honglei Gou, Zoraida P Aguilar, Shouwu Guo, Alice K Melconian, Abdul Kareem A Al-Kazaz, Fanke Meng, Nianqiang Wu, “ Detection of the ovarian cancer biomarker CA-125 using chemiluminescence resonance energy transfer to graphene quantum dots. Chemical Communications, 2014, Vol. 50, No. 11:1344-1346, doi:10.1039/c3cc47701k