Mn2+-ZnSe/ZnS@SiO2 Nanoparticles for Turn-on Luminescence Thiol Detection

Abstract

Biological thiols are antioxidants essential for the prevention of disease. For example, low levels of the tripeptide glutathione are associated with heart disease, cancer, and dementia. Mn2+-doped wide bandgap semiconductor nanocrystals exhibit luminescence and magnetic properties that make them attractive for bimodal imaging. We found that these nanocrystals and silica-encapsulated nanoparticle derivatives exhibit enhanced luminescence in the presence of thiols in both organic solvent and aqueous solution. The key to using these nanocrystals as sensors is control over their surfaces. The addition of a ZnS barrier layer or shell produces more stable nanocrystals that are isolated from their surroundings, and luminescence enhancement is only observed with thinner, intermediate shells. Tunability is demonstrated with dodecanethiol and sensitivities decrease with thin, medium, and thick shells. Turn-on nanoprobe luminescence is also generated by several biological thiols, including glutathione, N-acetylcysteine, cysteine, and dithiothreitol. Nanoparticles prepared with different ZnS shell thicknesses demonstrated varying sensitivity to glutathione, which allows for the tuning of particle sensitivity without optimization. The small photoluminescence response to control amino acids and salts indicates selectivity for thiols. Preliminary magnetic measurements highlight the challenge of optimizing sensors for different imaging modalities. In this work, we assess the prospects of using these nanoparticles as luminescent turn-on thiol sensors and for MRI.

Recent progress in 0D optical nanoprobes for applications in the sensing of (bio)analytes with the prospect of global health monitoring and detailed mechanistic insights

“…Recently, QDs have been extensively used for sensing various biomolecules, such as ascorbic acids, proteins, tumor markers, glucose, dopamine, and biothiols such as Cys, GSH etc (Table 3). 125–143…”

“…Recently, QDs have been extensively used for sensing various biomolecules, such as ascorbic acids, proteins, tumor markers, glucose, dopamine, and biothiols such as Cys, GSH etc (Table 3). [125][126][127][128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143] Ascorbic acid (AA) is one of the most important nutrients in the human body as it plays a pivotal role in different physiological functions such as anti-oxidant effects, immunity improvement, etc. 144 Ascorbic acid oxidase (AAO), an enzyme containing copper ions, can catalyze the redox reaction between oxygen and AA to generate dehydroascorbic acid (DHA) and water.…”

Use of metal nanoparticles for preconcentration and analysis of biological thiols

“…The oxidation (and therefore the fluorescence) is blocked, when MnO 2 nanosheets are again reduced to Mn 2+ in the presence of GSH. Further, Mn 2+ ‐doped wide bandgap semiconductor nanocrystals and silica‐encapsulated NP derivatives with addition of the ZnS shell for stabilization (Mn 2+ :ZnSe/ZnS@SiO 2 NPs) were tested as a turn‐on luminescence probe that allows nonselective determination of Cys, GSH, NAC, and DTT [133]. Interestingly, ZnS shell thickness enables tuning the analyte sensitivity.…”