Chiral Melanin-like Particle-Inspired Fluorescent Silicon Quantum Dots for Sensitively Detecting Inflammation in Cells

An abnormal concentration of ONOO- is a major contributor to inflammation and cancer. Thus, real-time detection of ONOO- concentrations is essential for the prevention of inflammation and cancer-related diseases. The fluorescence of melanin-like particles synthesized by oxidizing the tripeptide LysTyr-Phe (KYF) with L-phenylalanine (L-Phe) can be specifically quenched by ONOO-. In order to decrease the photobleaching of melanin-like particles ((K/P)(ox)) and retain the ability to detect ONOO- specifically, chiral SiQDs-( K/P) (ox) with (K/P) ox as precursor was synthesized by a one-step hydrothermal route. Compared to SiQDs-Cat, which is synthesized with catechol as the precursor, SiQDs-(K/L-P) (ox) and SiQDs-(K/D-P) (ox) have a wider emission interval (380-700 nm) with a maximum emission wavelength of 490 nm. Among them, SiQDs-(K/D-P) (ox) exhibits a higher quantum yield (47.66%) and SiQDs-(K/L-P) (ox) has a longer fluorescence lifetime (27.219 mu s). Additionally, SiQDs-(K/L-P) (ox) shows higher biocompatibility and can be colocalized in the mitochondria of HepG2 cells with a Pearson coefficient of 0.99. Furthermore, SiQDs-(K/L-P) (ox) can sensitively detect endogenous ONOO- in HepG2 cells by '' fluorescence off ''. Therefore, the development of chiral SiQDs-(K/L-P) (ox) provides an important alternative for sensitively detecting inflammation in cancer cells.