Mesoporous silica nanoparticles-based fluorescent mini sensor array with dual emission for discrimination of biothiols

Abstract

Development of novel functional silica nanoparticles has drawing great attention in the field of fluorescent sensing as they provide advantages in term of versatile functionalization, high stability, and good biocompatibility. In the present work, a dual-fluorophore-functionalized mesoporous silica nanoparticle was designed and fabricated, where two silanized fluorophores, NAA and RB-2, were chemically bound to the nanoparticle surface. A series of measurements including TEM, BET, FT-IR, TGA and XPS were carried out to characterize the morphology variation and verify the surface functionalization. Fluorescence measurements revealed that the fluorescent nanoparticle displayed typical naphthalene and rhodamine emission bands, where the naphthalene units exhibited weak fluorescence emission due to the modification of 2,4-dinitrobenzenesulfonyl group (DNBS). The reaction with biothiols led to departure of DNBS group and thereby recovered the fluorescence of naphthalene unit. The presence of different biothiols resulted in different extents of fluorescence changes of naphthalene and rhodamine. Moreover, the dual-fluorophore functionalized nanoparticle at different concentration showed different responses to the same biothiol and was used as sensing element to construct a two-element sensor array. By collecting the four signals, the mini sensor array could provide distinct recognition pattern and can realize fingerprint discrimination of the four biothiols (H2S, Cys, Hcy, GSH) in aqueous solution and human serum.