Constructing Ultrasensitive Biosensor for Biomarker Detection of Early Diseases Through G-Quadruplex Probe Coupled with Aggregation-Induced Electrochemiluminescence Platinum(Ii) Complexes

Abstract

Highly sensitive and simple biomarker determination is crucial for diagnosis and treatment of early diseases. However, it remains a tremendous challenge for rapid, accurate and real time detection of biomarkers at the early stage of diseases due to its extremely low content and serious interference. Herein, we have successfully constructed an ultrasensitive electrochemiluminescence (ECL) biosensor based on 2,6-bis(2-benzimidazolyl)pyridine platinum(II) (BZIMPY-Pt) complexes with aggregation-induced electrochemiluminescence (AIECL) phenomenon, which was utilized to detect miRNA-155 at early diseases. The BZIMPY-Pt complexes with AIECL properties and had high affinity with G-quadruplex DNA compared to other square planar pyridyl Pt(II) complexes, which exhibited 13-fold enhancements in ECL intensity in the aggregated state. The constructed biosensor possessed high sensitivity, wide linear range (1 fM-10 nM), low limit of detection (~0.22 fM), high selectivity and good stability and reproducibility for miRNA-155 detection. The ECL biosensor was successfully applied to determine miRNA-155 in the serum samples of early-stage diagnose. This AIECL-based strategy overcomes traditional limitations in low-abundance biomarker analysis through synergistic signal amplification and background suppression mechanisms, which is potential for clinical diagnosis of early diseases.

Keywords: biosensor, Electrochemiluminescence, Disease detection, Platinum complex, G-quadruplex