High-performance electrochemical immunosensor based on bimetallic gold/silver functionalized carbon spheres for CYFRA 21-1 detection and information protection.

Bimetallic nanomaterial-based systems have been widely utilized across various fields due to their remarkable expandability and flexibility, including nanomedicine, diagnostics, and molecular information technology. Here, we constructed an electrochemical immunosensor using bimetallic gold/silver functionalized carbon spheres (AuAg@CSs) and mesoporous silica nanoparticles (MSNs) for the sensitive determination of cytokeratin 19 fragment antigen 21-1 (CYFRA 21-1) and ensuring information protection for textual data. The AuAg@CSs demonstrated exceptional catalytic activity towards hydrogen peroxide, generating a significant current signal. The introduction of CYFRA 21-1 facilitated the binding of MSNs, thereby forming a sandwich-type electrochemical immunosensor that resulted in a notable decrease in current. Notably, the detection limit for CYFRA 21-1 was determined to be 31 fg mL, accompanied by high selectivity. Furthermore, extensive textual information can be encrypted and concealed within the current responses of the electrochemical nanosensing system. By establishing a threshold, these current signals can be represented as a series of binary strings, which can subsequently be segmented into shorter strings. Through information coding methods, these shorter binary strings can be assembled and decrypted, ultimately merging into meaningful textual content. This study promotes the synthesis and multifunctional application of bimetallic nanomaterials, providing innovative solutions to enhance the sensing sensitivity of electrochemical immunosensors and paving the way for advancements in molecular digitization.