Self-enhanced luminescence of copper nanowires combined with pH-sensitive glycosyl imprinted polymers: Electrochemiluminescence for high-sensitivity detection of sialic acid

It is of great significance to explore a low cost and high sensitivity sialic acid (SA) detection method for early diagnosis and prognosis of cancer. Electrochemiluminescence (ECL) has aroused many scholars' interest in the accurate analysis of multi-domain analytes for its excellent performance. In order to improve the ECL signal strength and the corresponding detection sensitivity, it is effective to develop new ECL reagents. Copper nanowires (CuNWs) as luminophor has always been a blank in the field of ECL sensors. In this study, a glycosyl imprinted electrochemiluminescence sensor (GIP-ECLS) for SA specificity detection in serum was developed using CuNWs as luminophor. CuNWs can not only form quasi-three-dimensional (3D) conductive network, but also realize self-enhancement of ECL signal through Cu²⁺ and Cu⁺ conversion. In addition, the excellent conductivity and wrapping properties of Ti₃C₂ provide a large electroactive area for electrode modification. More importantly, 3-aminobenzenoboric acid (3-ABA) specifically binds to SA to form B-N or B-O, which lays the foundation for selective recognition of SA. Under optimal conditions, the signal response of GIP-ECLS showed a good linear relationship with SA concentration at 5 × 10⁻¹²–1 × 10⁻⁸ mol L⁻¹ (R² = 0.997), and the limit of detection (LOD) was 1.17× 10⁻¹² mol L⁻¹. The results showed that in the actual sample analysis, the recovery rate of SA detected by GIP/Ti₃C₂/CuNWs/GCE was good, and it had good selectivity and stability, which provided ideas for designing minimally invasive and highly sensitive detection of SA in serum samples.