A novel light-electricity sensing method for PCSK9 detection based on s-PdNFs with multifunctional property

Amounts of studies show that proprotein convertase subtilisin/kexin type 9 (PCSK9) can increase the low-density lipoprotein cholesterol ((LDL-C), leading to the progression and development of atherosclerosis. Hence, design an effective method to detect serum PCSK9 is meaningful for the prevention, monitor and diagnosis of cardiovascular diseases. Here, we reported a dual-signal method for detecting PCSK9 using a signal label, sulphur-doped palladium nanoflowers (s-PdNFs), inspired by its multifunctional properties of quenching and catalysis, which would simultaneously achieve electrochemiluminescence (ECL) analysis and electrochemical detection. For the ECL analysis, s-PdNFs could effectively quench the ECL intensity of peroxydisulfate/oxygen (S₂O₈^2-/O₂) system via ECL resonance energy transfer (ECL-RET). Importantly, the donor-acceptor pair (s-PdNFs-S₂O₈^2- pair) was firstly reported in the ECL-RET field. For the electrochemical detection, s-PdNFs with peroxidase-like activity, produce electric signals by catalyzing H₂O₂. Herein, a novel light-electricity dual signal immunosensor based on s-PdNFs was developed, and with a broad linear range of 5 fg mL^-1 to 50 ng mL^-1 (ECL channel) and 500 fg mL^-1 to 50 ng mL^-1 (electrochemical channel). Furthermore, the ECL channel and electrochemical channel can achieve the detection respectively which can meet different testing instruments. The two channels can also be combined to improve the accuracy of the detection. More importantly, the immunosensor realized the detection of PCSK9 in real serum samples demonstrated by good correlations with ELISA method. Our findings can promote the application of multifunctional materials in sensor and biomedicine field and provide a novel strategy for the detection of serum molecular.