Small-Molecule Self-Assembly Strategy for Ultrafast, Sensitive, and Portable Multiplexed Antibiotics Detection by Transistor Biosensor Arrays

The urgent need for portable, sensitive, and accurate techniques to analyze multiple antibiotics is critical to mitigating the health risks associated with low-dose antibiotics coexposure-induced drug resistance, especially in infants. Emerging field-effect transistor (FET) biosensors are expected to realize the above requirement, but face challenges in terms of sensitivity and selectivity for complex solutions in practical applications. Here, we introduce a small-molecule coating strategy on carbon nanotube (CNT)-FET biosensor arrays to simultaneously block nonspecific adsorption and minimize Debye shielding effects, coupled with aptamer for antibiotics recognition through inkjet printing technology, which significantly improves the selectivity and sensitivity. The developed portable detection system with the FET biosensor chip displayed an ultrafast response time of 100 s, high sensitivity at the femtomolar level for both simultaneous detection and quantification of multiple antibiotics (kanamycin, oxytetracycline, and sulfaquinoxaline), a wide linear range from femtomolar to nanomolar concentrations, and exceptional accuracy, with a recovery rate of 91.1 to 107.5%. This work presents a biosensor array that can quantify various antibiotics at extremely low concentrations in milk samples, is superior to the enzyme-linked immunosorbent assay (ELISA) method, and can also be applied for the detection of other biomarkers, such as toxins and hormones.