Cu-Based Tris(chloropropyl) Phosphate MOF Nanosheets for Surface Plasmon Resonance-Based Fiber-Optic Biosensing

Two-dimensional(2D) metal-organic frameworks (MOFs) havepromising applications in surface plasmon resonance (SPR) sensingfor their intriguing exciton migration and visible light-near infraredabsorption properties. In this study, an effective biosensing structurecomprising 2D Cu-TCPP MOF nanosheet-capsulated Au film was developed,such that lower molecular-weight dopamine with small changes of refractiveindex can be identified on the fiber-optic platform. The large areasof ultrathin 2D Cu-TCPP MOF nanosheets were well prepared, the experimentalresults indicated that the sensitivity (48%) and figure of merit (18%)were increased notably compared with the bare Au film. Moreover, thefinite element method was adopted to numerically analyze and verifythe excellent charge-transfer ability of MOF nanosheets and the bidirectionalgain properties between MOF nanosheets and Au films. Furthermore,the sensitivity [1.24 nm/log(M)] and selectivityof the dopamine were significantly enhanced with a low limit of detectionof 1.50 x 10(-13) M and linear response witha wide range of concentrations from 5 x 10(-12) M to 5 x 10(-7) M through ssDNA surface modificationand conformation amplification. As revealed by the above-mentionedresults, the Cu-TCPP/Au/SMF biosensor can serve as a promising nanoplatformfor clinical diagnosis and medical assessment.