Design and performance of IFN-γ and UO22+ detections using a PGM. a, IFN-γ-mediated release of immobilized DNA–invertase conjugates. b, IFN-γ detection in buffer using the PGM. c, IFN-γ detection in 20% human serum samples using the PGM. d, UO22+-mediated release of immobilized DNA–invertase conjugates. e, UO22+ detection using the PGM. f, Selectivity of UO22+ detection using the PGM: (1) 50 nM UO22+; (2) 1 μM UO22+; (3) 1 μM Pb2+; (4) 1 μM Cd2+; (5) 100 μM Ca2+/Mg2+; (6) 1 μM Zn2+/Cu2+; (7) 1 μM Co2+/Ni2+; (8) 1 μM VO+; (9) 1 μM Th4+; (10) no metal ion. All error bars were obtained through the detection of three parallel samples.