Nitrogen Functionalized Siloxane‐Based Quantum Dots as a Photoluminescent Platform for Sensing and Cellular Imaging Applications

Photoluminescent quantum dots are efficient for sensing environmental pollutants and also for cellular imaging applications. We present here nitrogen‐functionalized siloxane‐network‐based quantum dots (named as N‐SiO ₂ QD) as a multifunctional probe for sensing highly toxic Cr(VI) and persistent pollutant 4‐Nitrophenol via photoluminescence (PL) quenching, and its application for cellular imaging. The N‐SiO ₂ QD is synthesized using the solvothermal method by heating (3‐aminopropyl)triethoxysilane and 1,4‐butanediol at 170°C for 12 h. Its structure, morphology, and composition are elucidated. An intense bluish PL of N‐SiO ₂ QD is obtained at λ = 443 nm when excited at 370 nm, which is systematically quenched by treating with Cr(VI) and 4‐nirophenol, and the quenching mechanism has been discussed. Their limit of detection is 0.20 ± 0.01 and 0.07 ± 0.01 µM, respectively. The application of N‐SiO ₂ QD for the detection of Cr(VI) and 4‐nitrophenol in real water matrix has been demonstrated. The cellular imaging capability of N‐SiO ₂ QD has been demonstrated by showing green and blue photoluminescence owing to its uptake in A549 lung cancer cells, while HEK293 normal cells displayed no significant uptake of N‐SiO ₂ QD under similar experimental conditions, suggesting scope for selective imaging of cancer cells.