A series of quinoline-based photo-removable protecting groups for photo-regulation of thrombin aptamer (HD1) activity were synthesized with improved caging and uncaging efficiency. Among them, 8-bromo-2-diazomethyl-7-hydroxyquinolinyl (BHQ-diazo, 1) chromophore was found to cage the HD1 with highest caging and restoration efficiency. Moreover, on the basis of the RP-HPLC and SPR analysis, BHQ was demonstrated to ...