Green synthesis of yellow-green emissive silicon nanoparticles and their application for the sensitive fluorescence detection of bilirubin.

Bilirubin, a tetrapyrrole compound metabolized by heme, is an important biomarker for diagnosis and prognosis of patients with liver diseases. Highly sensitive detection of bilirubin is essential for disease prevention and treatment. In recent years, silicon nanoparticles (SiNPs) have received intense attention due to their excellent optical properties and environmental friendliness. In this paper, water-soluble yellow-green fluorescent SiNPs were synthesized by a mild water bath method using 2-aminophenylboronic acid hydrochloride as the reducing agent and 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (AEEA) as the silicon source. The preparation process does not require high temperature, high pressure and complex modifications. The SiNPs possessed excellent photostability and good water dispersibility. It was found that the fluorescence of SiNPs at 536 nm could be significantly quenched by bilirubin. By using SiNPs as a fluorescent probe, a novel fluorescence method for sensitive detection of bilirubin was established with a wide linear range of 0.05-75 μM and a limit of detection (LOD) of 16.67 nM. The detection mechanism was mainly due to the internal filtration effect (IFE). More significantly, the established method could successfully determine the contents of bilirubin in biological samples with good recoveries.