A Signal-Switchable Fluorescent-Colorimetric Dual-Signal Probe for Detection of Sunitinib Based on D-Penicillamine-Functionalized Silicon Nanoparticles

Sunitinib (SNTN), a multi-target receptor tyrosine kinase (RTK) inhibitor, plays a significant role in the clinical treatment of renal cell carcinoma (RCC). However, drug resistance to this agent severely restricts its long-term clinical efficacy. Therefore, the development of a precise platform for SNTN monitoring has become an important research direction. In this study, D-penicillamine-functionalized silicon nanoparticles (DPA-SiNPs) with low toxicity and excellent photostability were synthesized via the hydrothermal method, using N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AEAPTMS) and D-penicillamine (DPA) as raw materials. Subsequently, DPA-SiNPs were used as a dual-signal sensor probe for fluorescence and colorimetry. SNTN quenches the fluorescence and UV-Vis absorption signals of DPA-SiNPs via the internal filtration effect (IFE). Based on this mechanism, a dual-signal detection system was established. The limits of detection for fluorescence and colorimetric dual-signal sensing were as low as 0.13 nM and 0.16 μM (S/N = 3), with good linear relationships in the ranges of 0.87-790.03 nM (R² = 0.992) and 3.95-76.30 μM (R² = 0.992), respectively.