Hemin/G-quadruplex functionalized porphyrin-based MOF nanozymes and their application in mediating long-lasting chemiluminescence optical fiber aptasensor for sensitive and accurate detection of ricin

A novel hemin/G-quadruplex functionalized porphyrin-based MOF nanozyme (HGP-PCN) was firstly synthesized and employed to fabricate a chemiluminescence (CL) assay strategy for ricin detection. Porphyrin-based MOFs with large specific area could fully expose their catalytic centers, provide functional interface to load hemin/G-quadruplex, and then generate “double catalytic activity amplification”. The catalytic mechanism of HGP-PCN was thoroughly illustrated by chemical characterizations and theoretical calculations. The continuous generation of •OH, O2•−, and 1O2 from H2O2 catalyzed by Fe-N4 active sites on the HGP-PCN nanozyme could induce long-lasting and stable CL signals, which is helpful to fabricate sensitive and accurate CL sensing platform. The HGP-PCN nanozymes mediated long-lasting CL optical fiber aptasensor (CN-LCOFA) was fabricated to quantify ricin. The ricin toxic B (RTB) chain aptamers labelled HGP-PCN (Apt-HGP-PCN) was used for signaling while functionalized optical fiber probe was used as biorecognition interface. The CN-LCOFA could ultra-sensitively detect ricin within 23 min, the dynamic linear range was 4.1~185.0 ng/mL, and the LOD was 1.28 ng/mL. The analytical performance of CN-LCOFA including detection time, detection range and LOD was significantly superior to the ricin detection methods that reported in currently literatures. The detection accuracy of CN-LCOFA for ricin spiked in human serum was comparable with that of HPLC-MS. This novel nanozyme-catalyzed long-lasting CL system and ultrasensitive assay strategy could provide effective methods for food safety and environmental monitoring.