Gd3+-nanoparticle-enhanced multivalent biosensing that combines magnetic relaxation switching and magnetic separation

Publication date: Available online 19 February 2020Source: Biosensors and BioelectronicsAuthor(s): Yunlei Xianyu, Yongzhen Dong, Zhuo Zhang, Zhanhui Wang, Wenbo Yu, Zhilong Wang, Yiping ChenAbstractIn this work, a multivalent magnetic biosensing strategy has been developed by integrating magnetic separation and magnetic relaxation switching (MRS) where Gd3+-loaded magnetic nanoparticles have been used. As a transition metal ion, Gd3+has multiple unpaired electrons in the d-orbitals that can induce a strong fluctuating magnetic field and thus can reduce the transverse relaxation time (T2), contributing to an enhanced magnetic signal. By loading Gd3+ onto magnetic nanoparticles, multivalent magnetic probes integrating magnetic separation and MRS for the signal readout are prepared. This multivalent sensing technique can simplify the procedures and greatly enhance the detection sensitivity of conventional MRS assays. A sensitive detection of ractopamine in real samples has been demonstrated with this multivalent sensing technique. The magnetic probe enables the detection of ractopamine in a linear range from 0.1 to 100 ng/mL and the limit of detection is 20 pg/mL, a 25-fold enhancement in the sensitivity compared with conventional assays. This Gd3+-nanoparticle-mediated MRS biosensor is a potential magnetic platform to detect trace levels of targets in complex samples.

Source: Biosensors and Bioelectronics - February 19, 2020 Category: Biotechnology Source Type: research