Opto/Catalytic Metal–Organic Framework Adjuvant-Empowered Acidolytic Nanozymes Amplified for Bimodal Glycoprotein Assay

Abstract

In this work, an adaptive fusion strategy of acidolytic nanozyme-based sandwich immunoreaction and metal–organic framework (MOF) adjuvants was developed for the inspired establishment of an enhanced glycoprotein assay, in which MOFs can function as dual-signal opto/catalytic adjuvants. The specific means toward the glycoprotein recognition pattern were guaranteed by both antigen recognition as well as glycosylated epitope binding through lectin affinity, and the immediate responses were initiated by textural acidolysis of the typical Fe₃O₄ nanozymes for signal generation. Upon the solid Fe₃O₄ particles being subjected to acidolytic decomposition, the signal generators can be harvested in an on-demand manner. On one hand, MOF adjuvants can exert adsorption leverage on the resultant acidolytic decomposition of Fe nodes toward fluorogenic MOFs, a process that results in quenching the fluorescence of MOFs. On the other hand, MOFs with affordable scaffold sites can function as catalytic adjuvants to operate cooperatively in the catalytic performance of the acidolytic Fe nodes, signifying their enhanced chromogenic reflection. For added benefits, an individual Fe₃O₄ particle is composed of abundant precursor Fe nodes, which can be harvested as an amplified means for signal generation. The dual-mode glycoprotein assay can reach a “signal-off” response for fluorescence output in a range of 0.02–2 nM with a detection limit of 4.37 pM and exhibit a “signal-on” chromogenic output in a range from 0.05 to 10 nM with a detection limit of 16.35 pM. Collectively, our proposed glycoprotein assay may provide a new idea in the binary fusion of MOF adjuvant-empowered acidolytic nanozymes harvested for dual-modal assay outputs, which may also have the potential for the rational substitution of other glycosylated binding lectins to broaden its application in versatile glycoprotein analysis.