Sensitive detection of placental growth factor using an aptasensor based on luminol-dissolved oxygen electrochemiluminescence enhanced by nanochannel-confined catalysis

Accurate detection of placental growth factor (PlGF) is crucial for early diagnosis, risk assessment, and clinical management of preeclampsia. Herein, we present an electrochemiluminescence (ECL) aptasensor targeting PlGF with high sensitivity, in which Ni(OH) 2 –CeO 2 composite nanocatalyst was confined in the vertically-order nanochanels to facilitate the ECL of luminol-dissolved oxygen (DO). These Ni(OH) 2 –CeO 2 composite nanocatalyst exhibited good catalytic performance towards oxygen reduction during electrochemical cathodic scanning and could catalyze the electrochemical oxidation of luminol anions. Compared to catalysts directly electrodeposited on indium tin oxide (ITO) electrode, the nanocatalyst confined within the ultra-small VMSF nanochannels demonstrated stronger ECL enhancement effects and higher stability. Additionally, the composite of Ni(OH) 2 and CeO 2 exhibited remarkable synergistic catalytic performance. By immobilizing PlGF recognition aptamer (Apt) on the VMSF surface, an aptasensor was constructed for the highly sensitive analysis of PlGF. Upon the capture of target PlGF (Ag) by recognition aptamer, the formed Apt-Ag complex blocking the nanochannel causes the hindered diffusion of luminol, ultimately leading to a decreased ECL signal for the quantitation of PlGF. Convenient, and sensitive detection of PlGF was achieved by the developed ECL aptasensor with wide linear range (10 fg/mL ∼ 10 ng/mL) and low limit of detection (LOD 1.2 fg/mL). Additionally, analysis of real human serum was realized. The aptasensor demonstrated good selectivity, anti-interference, reproducibility, and long-term storage stability.