A fluorescent aptasensor for highly sensitive and selective detection of carcinoembryonic antigen based on upconversion nanoparticles and WS nanosheets.

A highly sensitive fluorescent aptasensor for carcinoembryonic antigen (CEA) was developed by employing upconversion nanoparticles (UCNPs) as an energy donor and WS nanosheets as an energy acceptor, respectively. Polyacrylic acid (PAA) modified NaYF4:Yb/Er UCNPs and an amine modified CEA aptamer were linked together by a covalent bond. Owing to the physical adsorption between WS nanosheets and the CEA aptamer, the UCNPs-aptamer was close to WS nanosheets, resulting in upconversion fluorescence energy transfer from UCNPs to WS nanosheets, and the UCNP fluorescence was quenched.

Research Progress on the Collaborative Drag Reduction Effect of Polymers and Surfactants.

Polymer additives and surfactants as drag reduction agents have been widely used in the field of fluid drag reduction. Polymer additives can reduce drag effectively with only a small amount, but they degrade easily. Surfactants have an anti-degradation ability.