Eu3+-Functionalized Covalent Organic Framework Hybrid Material as a Sensitive Turn-On Fluorescent Switch for Levofloxacin Monitoring in Serum and Urine.

The research on luminescent lanthanide-functionalized covalent organic framework (COF)-based hybrid materials has not been reported so far. When a straightforward functionalized modification strategy is employed, a chemical stable Eu3+-modified COF hybrid material, Eu@TpPa-1, is first developed. The functional process does not affect the size and shape of TpPa-1, but after the introduction of Eu3+, Eu@TpPa-1 as a fluorescence sensor exhibits a turn-on response toward levofloxacin. Eu3+ plays a bridge role in the whole detection system, and TpPa-1 serves as a host matrix to provide protection for the introduced Eu3+. This reusable sensor shows strong pink-white and yellow emissions toward the high and low concentration ranges of levofloxacin, respectively. It displays excellent sensitivity and fast response to levofloxacin within 1 min, while refraining from the interference of other coexisting species in serum and urine. The good selectivity and high antidisturbance lead Eu@TpPa-1 to be successfully applied in serum and urine systems for sensing levofloxacin.