期刊
ANALYTICAL SCIENCES
卷 38, 期 2, 页码 317-322出版社
SPRINGERNATURE
DOI: 10.2116/analsci.21P257
关键词
Surface plasmon resonance; A beta(40) oligomer; Aptamer; Copper; Affinity
资金
- National Natural Science Foundation of China [21573290]
- State Key Laboratory of Fine Chemicals, Dalian University of Technology [KF1910]
- Open Research Fund of State Key Laboratory of Physical Chemistry of Solid Surface, Xiamen [201814]
- Hunan Provincial Science and Technology Plan Project, China [2019TP1001]
This study investigated the interference of Cu2+ in the interaction between A beta(40) oligomer (A beta O-40) and its aptamer (Apt) using surface plasmon resonance spectroscopy. The results showed that Cu2+ binding to Apt resulted in changes to its structure and affinity for A beta O-40. Real sample analysis revealed significant errors caused by Cu2+ in cerebrospinal fluid (CSF) and serum analysis. Further studies demonstrated that EDTA can eliminate the interference of Cu2+ on the A beta O-40/Apt system.
Aptamers are widely used as a recognition element for Alzheimer's disease (AD)-related biomarker determinations. Due to the existing Cu2+ in real samples, and its possible coordinations with aptamers and biomarkers, the aptamer-based biomarker determination could be seriously disturbed. In this work, taking A beta(40) oligomer (A beta O-40, a typical biomarker for AD) as a model, the interference of Cu2+ in the interaction between A beta O-40 and its aptamer (Apt) was investigated by surface plasmon resonance spectroscopy. The results demonstrated the binding of Cu2+ to Apt, resulting in significant changes on the original structure of Apt, and the affinity of Apt to A beta O-40. The affinity of Apt-Cu2+/A beta O-40-Cu2+ (K-d: 1.36 mu M) was 17 times weaker than that of Apt/A beta O-40 (K-d: 0.08 mu M), which induced a poor dynamic range in the Cu2+-involved A beta O-40 determination. The analysis of A beta O-40-spiked real samples revealed that the existing Cu2+ resulted in significant positive errors in CSF analysis, but also complicated errors in serum analysis that depended on the blood collection. Further studies confirmed that EDTA can completely chelate Cu2+ from Apt-Cu2+ and A beta O-40-Cu2+, eliminating the interference of Cu2+ on the A beta O-40/Apt system. Therefore, excess EDTA is highly recommended for Apt-based CSF and blood analysis, even if the samples are from EDTA- or other metal ion chelating agent-involved collection tubes. This work quantitatively revealed the interference of Cu2+ and provided a simple but effective approach to eliminate the interference, which will improve the existing method to achieve accurate Apt-based biomarker detection in real samples.
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