Aqueous synthesis of Ag and Mn co-doped In2S3/ZnS quantum dots with tunable emission for dual-modal targeted imaging

Publication date: Available online 18 December 2016
Source:Acta Biomaterialia
Author(s): Pei-Yu Lai, Chih-Ching Huang, Tzung-Han Chou, Keng-Liang Ou, Jia-Yaw Chang
Here, we present the microwave-assisted synthesis of In2S3/ZnS core/shell quantum dots (QDs) co-doped with Ag⁺ and Mn²⁺ (referred to as AgMn:In2S3/ZnS). Ag⁺ altered the optical properties of the host QDs, whereas the spin magnetic moment (S = 5/2) of Mn²⁺ efficiently induced the longitudinal relaxation of water protons. To the best of our knowledge, this is the first report of the aqueous synthesis of color-tunable AgMn:In2S3/ZnS core/shell QDs with magnetic properties. The synthetic procedure is rapid, facile, reproducible, and scalable. The obtained QDs offered a satisfactory quantum yield (45%), high longitudinal relaxivity (6.84 s^–1 mM^–1), and robust photostability. In addition, they exhibited excellent stability over a wide pH range (5–12) and high ionic strength (0.15–2.0 M NaCl). As seen by confocal microscopy and magnetic resonance imaging, AgMn:In2S3/ZnS conjugated to hyaluronic acid (referred to as AgMn:In2S3/ZnS@HA) efficiently and specifically targeted cluster determinant 44, a receptor overexpressed on cancer cells. Moreover, AgMn:In2S3/ZnS@HA showed negligible cytotoxicity in vitro and in vivo, rendering it a promising diagnostic probe for dual-modal imaging in clinical applications.

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