Smilax China-derived yellow-fluorescent carbon dots for temperature sensing, Cu<sup>2+</sup> detection and cell imaging
Dan Chang, Lihong Shi, Yan Zhang, Guomei Zhang, Caihong Zhang, Chuan Dong, Shaomin Shuang
Abstract
Here, we report an environmentally friendly fabrication strategy of bright yellow fluorescent carbon dots (y-CDs) and construct a rapid and accurate multifunctional sensing platform for the effective detection of temperature and Cu2+. The y-CDs were favorably obtained through a one-step hydrothermal treatment of natural Smilax China for the first time and exhibit long-wavelength emission at 542 nm under an excitation wavelength of 470 nm. Additionally, the obtained y-CDs exhibit superior biocompatibility and distinguished stability under different conditions, and display a respectable fluorescence quantum yield of up to 22.37%. Appealingly, the as-prepared y-CDs were implemented as temperature probes within ranges of 25 °C-40 °C and 45 °C-80 °C. Significantly, based on the static quenching effect, the as-prepared y-CDs were developed as an effective platform for fluorescence sensing of Cu2+, with linear ranges of 0.5 μM-10 μM, 75 μM-225 μM and 250 μM-350 μM, achieving a detection limit of 28 nM. Furthermore, confocal fluorescence imaging of PC12 cells was achieved successfully, which indicated that the as-synthesized y-CDs could visualize Cu2+ fluctuations in living cells.