Silicon nanoparticles: fluorescent, colorimetric and gel membrane multiple detection of Cu2+ and Mn2+ as well as rapid visualization of latent fingerprints

In this paper, silicon nanoparticles (Si NPs) were synthesized by a simple one-step procedure by applying uric acid as reducing agent. The as-prepared Si NPs exhibited emission at 425 nm under excitation at 345 nm, allowing them to be developed as a fluorescent and colorimetric probe for detection of Cu2+ and Mn2+. As a probe, the fluorescence and color change of the Si NPs induced by Cu2+ and Mn2+ exhibited contrast. As a fluorescence probe, the Si NPs exhibited intense enhancement caused by Cu2+ and Mn2+ with detection limits of 0.562 μM (Cu2+) and 1.02 μM (Mn2+). More significantly, the Si NPs could be applied to effectively detect Cu2+ and Mn2+ in real samples. Interestingly, a Si NPs-based gel membrane was fabricated and established to be selective for visual recognition of Cu2+ and Mn2+. A cell imaging experiment revealed that the Si NPs possessed excellent biocompatibility and low cytotoxicity in living cells. Additionally, the powder form of the Si NPs can be easily prepared and used to visualize latent fingerprints (LFPs) with good performance.