Magnetic-responsive upconversion luminescence resonance energy transfer (LRET) biosensor for ultrasensitive detection of SARS-CoV-2 spike protein

• DOI: 10.1016/j.bios.2023.115969
• Publication Date: 2023-12-23T16:46:50Z
• Authors: Jiareng Chen; Willis Kwun Hei Ho; Bohan Yin; Qin Zhang; Chuanqi Li; Jiaxiang Yan; Yingying Huang; Jianhua Hao; Changqing Yi; Yu Zhang; Siu Hong Dexter Wong; Mo Yang
• Keywords: Luminescence; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Fluorescence Resonance Energy Transfer; Humans; Metal Nanoparticles; COVID-19; Nanoparticles; Gold; Biosensing Techniques; Antibodies

Upconversion nanoparticles (UCNPs) are ideal donors for luminescence resonance energy transfer (LRET)-based biosensors due to their excellent upconversion luminescence properties. However, the relatively large size of antibodies and proteins limits the application of UCNPs-based LRET biosensors in protein detection because the large steric hindrance of proteins leads to low energy transfer efficiency between UCNPs and receptors. Herein, we developed a magnetic responsive UCNPs-based LRET biosensor to control the coupling distance between antibody-functionalized UCNPs (Ab-UCNPs) as donors and antibody-PEG linker-magnetic gold nanoparticles (Ab-PEG-MGNs) as acceptors for ultrasensitive and highly selective detection of SARS-CoV-2 spike proteins. Our results showed that this platform reversibly shortened the coupling distance between UCNPs and MGNs and enhanced the LRET signal with a 10-fold increase in the limit of detection (LOD) from 20.6 pg/mL without magnetic modulation to 2.1 pg/mL with magnetic modulation within 1 h. The finite-difference time-domain (FDTD) simulation with cyclic distance change confirmed the distance-dependent LRET efficiency under magnetic modulation, which supported the experimental results. Moreover, the applications of this magnetic-responsive UCNP-based LRET biosensor could be extended to other large-size biomolecule detection.