Analyte-responsive gated hollow mesoporous silica nanoparticles exhibiting inverse functionality and an AND logic response

Abstract

A multifunctional nanoparticle with designed selectivity was made using hollow mesoporous silica, ship-in-a-bottle synthesis of a crystalline solid-state detector, and protection of the crystal by acid-responsive nanogates. The system demonstrates the inverse application of the usual trapping of contents by the gate followed by their release. Instead, the gate protects the contents followed by selective exposure. Crystallization of [Pt(tpy)Cl](PF₆) (tpy = 2,2′:6′,2′′-terpyridine) inside the cavity of hollow mesoporous silica created the unique core/shell nanoparticle. The crystalline core becomes fluorescent in the presence of perchlorate. By condensing an acid-sensitive gate onto the particle, access to the pores is blocked and the crystal is protected. The new nanomaterial obeys Boolean AND logic; only the presence of both the analyte (ClO₄⁻) and acid results in the optical response.