Novel Plasmon-Enhanced Fluorescence Sensing Platform Based on rGO/MoS2 Films for Ultrasensitive Detection of Protamine and Heparin

In comparison with the traditional metallic surface plasmons (SPs), graphene and molybdenum disulfide SPs that have less optical loss, coupled with affordability and a broader SP resonant frequency are anticipated to offer more evident luminescence enhancement to the light emitters. In the current work, we report a novel plasmon-enhanced fluorescence platform based on the reduced graphene oxide/molybdenum disulfide (rGO/MoS2) films for the enhancement of the fluorescence of carbon dot (CDs) self-assembled multilayers (SAMs). In the meantime, rGO/MoS2 films have larger fluorescence enhancement efficiency (ca. 8.3 times) according to the surface-plasmons resonance synergy effect as compared with the single rGO and MoS2 films. This sensing platform could be put to use for the "on–off–on" detection of protamine (Pro) and heparin (Hep), having been fully utilized for designing an "AND" logic gate based on SAMs. Also, it was discovered that the sensitivities for the detection of Pro and Hep on the basis of the CDs SAMs with rGO/MoS2 films were more than 120 times and 20 times those of the fluorophore that was not connected to the rGO/MoS2 films, respectively. The limit of detection of this sensing system amounted to 18.50 pg/mL (Pro) and 2.770 pg/mL (Hep), 1–5 orders of magnitude less in comparison with those of the majority of the fluorescence sensors indicated. More significantly, the established rGO/MoS2-enhanced fluorescence system could be further put to use for the purpose of investigating Pro and Hep in human serum samples.