Fluorescence sensor based on molecularly imprinted polymers and core–shell upconversion nanoparticles@metal–organic frameworks for detection of bovine serum albumin

A novel strategy for sensing protein was proposed through combining the high selectivity of molecular imprinting technology with the excellent upconversion fluorescence of upconversion nanoparticles (UCNPs) and high specific surface area of metal-organic frameworks (MOFs). Herein, the UCNPs acted as signal reporter and MOFs were introduced to increase the rate of mass transfer. The UCNPs@MIL-100 as support material was prepared via a step-by-step method. The imprinted material-coated UCNPs@MIL-100 (UCNPs@MIL-100@MIPs) were obtained by sol-gel technique. The results showed that as the increase of the template protein concentration, the fluorescence intensity of UCNPs@MIL-100@MIPs quenched gradually, and the imprinting factor was 2.90. The linear in the range of 1.00 to 8.00 μM, and the detection limit was 0.59 μM. Therefore, the novel optosensing material is very promising for future applications.