<p> A highly selective and sensitive silicon nanoparticles (Si NPs) biosensor was developed&#xa0;for dopamine (DA)&#xa0;detection&#xa0;utilizing synchronous fluorescence spectroscopy (SFS). Si NPs were synthesized via a one-step hydrothermal method, utilizing 3-aminopropyltriethoxysilane (APTES) as the silane precursor and polyethyleneimine (PEI) as the reducing agent. The Si NPs exhibited a spherical morphology, with an average diameter of 3.7 nm. Additionally, the Si NPs demonstrated remarkable fluorescent properties. When integrated into the DA detection process utilizing SFS, the synchronous fluorescence spectrum of the DA system exclusively exhibits a peak at 530 nm, whereas systems involving epinephrine and norepinephrine both display peaks at 484 nm and 530 nm. Consequently, this detection system exhibits a high capacity for effectively differentiating between DA and other catecholamines (epinephrine and norepinephrine), ensuring a high degree of specificity in the detection process. Additionally, this combined approach also presents a strong linear relationship between the enhancement of synchronous fluorescence intensity (F₅₃₀/F₄₈₄) and DA concentrations within the concentration ranges 1–10 <i>μ</i>M and 10–50 <i>μ</i>M, respectively. The limit of detection (LOD) was 0.22 <i>μ</i>M (3<i>σ</i>/<i>k</i>). Finally, the biosensor was successfully employed for the detection of DA in the spiked serum&#xa0;samples. This work introduced a novel approach for DA detection and provided a valuable technical platform for rapid monitoring of DA levels in biological samples.</p> Graphical abstract <p></p>