Ultrasensitive
Electrochemiluminescence Biosensor
with Silver Nanoclusters as a Novel Signal Probe and α‑Fe2O3–Pt as an Efficient Co-reaction Accelerator
for Procalcitonin Immunoassay
posted on 2023-01-04, 02:03authored byXianzhen Song, Lu Zhao, Nuo Zhang, Lei Liu, Xiang Ren, Hongmin Ma, Xuan Kuang, Yuyang Li, Chuannan Luo, Qin Wei
Herein,
a high-efficiency biosensor based on ternary
electrochemiluminescence
(ECL) system was constructed for procalcitonin (PCT) detection. Specifically,
silver nanoclusters (Ag NCs) with stable luminescence properties were
prepared with small-molecule lipoic acid (LA) as the ligand, and its
ECL emission in persulfate (S2O82–) was first reported. Meanwhile, the prepared Ag NCs possessed ligand-to-metal
charge-transfer characteristics, thus transferring energy from LA
to Ag+ for luminescence. Based on the small particle size,
good biocompatibility, and molecular binding ability, Ag NCs-LA was
used as an ideal luminescent probe. In addition, α-Fe2O3–Pt was introduced to facilitate the activation
of S2O82–, thereby generating
more sulfate radicals to react with the free radicals of Ag NCs to
enhance ECL emission. The synergistic effect of the variable valence
state of transition metals and high catalytic activity of noble metals
endows α-Fe2O3–Pt with excellent
catalytic ability for S2O82–. Importantly, the sensing mechanism was systematically demonstrated
by UV–vis, fluorescence, and ECL analysis, as well as density
functional theory calculations. At last, NKFRGKYKC was designed for
specific immobilization of antibodies, thus releasing the antigen
binding sites to improve the antigen recognition efficiency. Based
on this, the developed biosensor showed high sensitivity for PCT detection,
with a wide linear range (10 fg/mL–100 ng/mL) and a low detection
limit (3.56 fg/mL), which could be extended to clinical detection
of multiple biomarkers.