Advancements in Dual‐Signal Aptasensors: Integrating SERS and Fluorescence for Enhanced Detection of Toxins, Pathogens, and Biomolecules, and Ions

ABSTRACT Aptasensors are advanced analytical tools that utilize aptamers, short single‐stranded oligonucleotides, to detect specific analytes through electrical or optical signals. Aptamers, selected via SELEX (Systematic Evolution of Ligands by Exponential Enrichment), are ideal for sensor applications due to their high specificity, sensitivity, and biostability. Surface‐enhanced Raman spectroscopy (SERS) has become a popular detection method, amplifying Raman signals using plasmonic substrates to detect individual molecules and specific vibrational bands. Dual‐mode aptasensors combine SERS with other detection techniques like fluorescence to enhance SERS performance. This dual approach overcomes challenges inherent in single‐mode sensors, such as variable substrates and limited detection ranges, resulting in improved sensitivity and specificity. These dual‐mode aptasensors have demonstrated impressive performance in detecting pollutants like aflatoxin B1 (AFB1), T‐2 toxin, ochratoxin A, and tetrodotoxin. For example, a dual‐signal aptasensor for T‐2 toxin exhibited linear relationships in both fluorescence and SERS signals, surpassing traditional methods. Similar sensors have achieved high recoveries for AFB1 detection in food samples. Moreover, dual‐mode aptasensors have shown potential in applications like cancer diagnostics, environmental monitoring, and food safety. Their broad applicability, high sensitivity, and reliable detection capabilities position dual‐mode aptasensors as a significant advancement in biosensing technologies.