One-Step Synthesis of Water-Soluble MoS₂ Quantum Dots via a Hydrothermal Method as a Fluorescent Probe for Hyaluronidase Detection

TLDR

Hyaluronidase cleaves hyaluronic acid into proangiogenic fragments, causing gold nanoparticle aggregation. The study develops a one‑step hydrothermal synthesis of water‑soluble MoS₂ quantum dots using ammonium tetrathiomolybdate and hydrazine hydrate. Fluorescence of the MoS₂ QDs is quenched by hyaluronic‑acid‑functionalized gold nanoparticles via a photoinduced electron‑transfer mechanism. The few‑layered (~2.8 nm) QDs show excitation‑dependent blue fluorescence that is restored when hyaluronidase cleaves HA, enabling a sensor with a 1–50 U mL⁻¹ linear range and a 0.7 U mL⁻¹ detection limit.

Abstract

In this work, a bottom-up strategy is developed to synthesize water-soluble molybdenum disulfide quantum dots (MoS2 QDs) through a simple, one-step hydrothermal method using ammonium tetrathiomolybdate [(NH4)2MoS4] as the precursor and hydrazine hydrate as the reducing agent. The as-synthesized MoS2 QDs are few-layered with a narrow size distribution, and the average diameter is about 2.8 nm. The resultant QDs show excitation-dependent blue fluorescence due to the polydispersity of the QDs. Moreover, the fluorescence can be quenched by hyaluronic acid (HA)-functionalized gold nanoparticles through a photoinduced electron-transfer mechanism. Hyaluronidase (HAase), an endoglucosidase, can cleave HA into proangiogenic fragments and lead to the aggregation of gold nanoparticles. As a result, the electron transfer is blocked and fluorescence is recovered. On the basis of this principle, a novel fluorescence sensor for HAase is developed with a linear range from 1 to 50 U/mL and a detection limit of 0.7 U/mL.