Triple Amplification of 3,4,9,10-Perylenetetracarboxylic Acid by Co2+-Based MOFs and Silver-Cysteine and Its Potential Application for Ultrasensitive Assay of Procalcitonin

In this work, a triple-amplified biosensor with a bioactivity-maintained peculiarity was constructed for quantitative procalcitonin (PCT) detection. As everyone knows, a strong electrochemiluminescence (ECL) signal is the premise to ensure high sensitivity for trace target detection. Hence, a valid tactics was developed to achieve signal amplification of luminophor, by use of Co2+-Based MOFs (ZIF-67) and silver-cysteine (AgCys). The ZIF-67 particles, which have much atomically dispersed Co2+, could play the role of co-reaction accelerator to catalyze S2O82- to generate abundant Co3+ and sulfate radical anion (SO4•-). Afterwards, a mass of Co3+ was reduced to more hydroxyl radicals (OH•) by H2O, thus ulteriorly reduced S2O82- to generate more SO4•-. Remarkably, S2O82- was reduced to SO4•- continuously with the recycling of Co2+ and Co3+, which realized an effective signal amplification. Meanwhile, the AgCys complex with superior catalysis and biocompatibility was prepared to further improve the ECL signal ...