Host–guest-recognition-based polymer brush-functionalized mesoporous silica nanoparticles loaded with conjugated polymers: A facile FRET-based ratiometric probe for Hg2+

• A facile ratiometric Hg2+ probe was fabricated based on core–shell silica nanoparticles as the scaffolds.
• Novel Hg2+ probe combined with the host–guest interaction on the polymer brush functionalized MSNs with conjugated PPV.
• The probe can selectively detect Hg2+ via FRET between PPV and AD-SRhB.
• Compared with AD-SRhB as probe, the novel probe can selectively detect Hg2+ from Fe3+ and Al3+.

This article reports a new strategy for constructing a fluorescence resonance energy transfer (FRET) based ratiometric sensor for Hg2+ detection with organic-inorganic hybrid mesoporous silica nanoparticles (MSNs) as the scaffolds. The fluorescent conjugated polymer of poly(p-phenylenevinylene) (PPV) as the donor is encapsulated into the MSNs and a spirolactam rhodamine-linked adamantane (AD-SRhB) as mercury ion-recognition element is introduced to cyclodextrin (CD) functionalized polymer brush on the shell of MSNs via the host–guest interaction. Upon the addition of Hg2+, the rhodamine spirocyclic ring opens, and the fluorescence (578 nm) of rhodamine is observed due to the FRET. This novel nanosensor can selectively detect Hg2+ ions with a detection limit of 4.2 μM. On the other hand, compared with pure AD-SRhB as probe, the novel ion probe fabricated by us can selectively detect Hg2+ from other correlative metal ions, especially Fe3+ and Al3+.

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