A chemiluminescence resonance energy transfer strategy and its application for detection of platinum ions and cisplatin

A novel chemiluminescence resonance energy transfer (CRET) system was developed and combined with a structure-switching aptamer for the highly sensitive detection of platinum. Platinum was chosen as a model analyte to demonstrate the generality of the new CRET system. This aptameric platform consisted of a streptavidin labeled aptamer against platinum and a streptavidin-coated magnetic bead for the selective separation of platinum-bound aptamer. The platinum–aptamer probe contained several guanine (G) bases bound to the 3,4,5-trimethoxyphenyl-glyoxal (TMPG) donor group at the 5′ end, a fluorescent acceptor (6-carboxy-2′,4,7,7′-tetrachlorofluorescein, TET) at the 3′ end, and a streptavidin aptamer sequence in which several base pairs were replaced by the G-G mismatch to induce the platinum-oligonucleotide coordination. The chemiluminescence (CL) generated by TMPG/G bases is transferred to the acceptor (TET). In the presence of platinum, the platinum–aptamer probe was folded such that the G bases at the 5′ end and TET at the 3′ were in close proximity. The complex was separated using streptavidin-coated magnetic beads by the addition of TMPG to form the TMPG/G bases complex. The ultraweak CL from the TMPG/G bases was strongly enhanced by TET. This novel CRET-based method can be easily performed with high limit of detection (50 ng·mL⁻¹) and selectivity over other metal ions. This technique provides a novel method for simple, fast, and convenient point-of-care diagnostics for monitoring proteins and metal ions.