Top-down produced CdSe quantum dots as an ultrasensitive SERS platform for the detection of uric acid

Semiconductor quantum dots (QDs) are of great interest for a wide range of applications. Herein, we report the top-down production of CdSe QDs with a super small size (about 3 nm) and high yield (14%). The as-produced QDs exhibit different optical properties from those of colloidal QDs. This is probably due to the generation of numerous bare edges during the process of silica-assisted ball-milling. The CdSe QD-based substrate could serve as a surface-enhanced Raman scattering (SERS) substrate for the ultrasensitive recognition of probe molecules at trace levels, which are mainly attributed to the special edge–edge interactions and charge transfer (CT) enhancement mechanism. The substrate exhibits good reproducibility, uniformity, and high enhancement factor (5.05 × 106) with an expansion of the ultra-low limit of detection (LOD) to 10−10 M. It has also been successfully used in the reliable, quantitative, and label-free detection of uric acid (UA) at a low concentration (1 μM), which facilitates the early prevention of gout disease. This QD-based platform not only confirms the feasibility of SERS analysis but also provides ideas for the early detection of residues.