SEARCH Articles Figures Tables Detection system direct conjugate-labeled antibody Direct ELISA labeled antibody Direct Method by Metabolical Labeling Direct conjugate-labeled antibody detection Direct detection of the nanoparticle label Direct labeling approach Direct labeling method Label-Free (Direct) Detection Labelling Clinical Trials Directive Labels direct primary Side-directed spin labeling Site-directed labeling Site-directed spin labelling Site-directed spin-labeling Site-directed spin-labeling rhodopsin Use of Thiolation Reagents for Direct Labeling to Sulfhydryl Groups