Fluorescent carbon quantum dots are emerging as a new class of fluorescent probes due to their unique optical properties . Herein, we presented a simple, one-pot and effective preparation strategy for copper-functionalized carbon quantum dots (Cu-CDs). The Cu-CDs demonstrated excitation-independent emissions, high fluorescent quantum yield (~ 24.4%) and excellent fluorescent stability. The fluorescence of Cu-CDs could be quenched efficiently in the presence of histidine (His) due to the coordination occurring between surface Cu and imidazole side chains of His. Thus, the Cu-CDs could be used as an efficient fluorescent probe for His detection. Under optimal conditions, the fluorescent signals of Cu-CDs decreased linearly with the concentrations of His over a range of 0.1–15 µM. The detection limit was 30 nM. The proposed method provided obvious advantages of rapid response, convenience, simplicity, high selectivity and sensitivity. Moreover, good results also have been obtained for His detection in real biological fluid samples.
As a luxurious textile for more than five thousand years, silk fibers/products have always been favored by consumers and the markets, but the poor photostability seriously hinders its utilization in fashionable apparel. Even if enduing the functionality of silk fiber through surface modification, it is often at the expense of its comfort. Here, an ultra-thin amorphous titanium dioxide nano-film with a thickness of only five in a thousand of fiber diameter and the add-on percentage ≤ 5.33% was prepared on the surface of silk fibers/fabrics by atomic layer deposition (ALD) methods. The tensile strength of the modified silk fiber maintains 89.17% of the original fiber after exposure to UV light for 672 h. They can also withstand multi-cycle laundering and accelerate light-aging, which exhibiting an excellent UV resistance. Most importantly, the functional coating has a negligible impact on the comfortable and wearability performance of silk fibers/fabrics. In addition, ALD-coated silk fabric is also further used as an outdoor reflective cooling material and achieving a superior thermal insulation effect with the temperature reduction up to 10.1 °C.