A nanoscale optical biosensor based on peptide encapsulated SWCNTs for detection of acetic acid in the gaseous phase

•A reusable optical biosensor based on drop-casted peptide encapsulated SWCNTs for the detection of acetic acid in the gaseous phase was developed.•The developed sensor shows a remarkable sensitivity to a low amount of acetic acid and is fully recoverable.•We demonstrate the detection of red wine spoilage based on excess gaseous acetic acid in its aroma. Biosensors play a key role in almost every field of human activity – ranging from biomedical diagnosis and point-of-care health monitoring to environmental monitoring and forensics. Single-walled carbon nanotubes (SWCNTs) are one of the most promising materials for near-infrared (NIR) fluorescence-based biosensing. Herein, we develop a reusable, drop-casted, real-time optical biosensor based on peptide-encapsulated SWCNTs for the detection of low concentrations of acetic acid in the air, at room temperature. While detection of NIR signal usually requires expensive and bulky equipment, here we use the (6,5) SWCNTs chirality whose peak fluorescence lies within the range of 970 nm – 1050 nm, enabling the usage of low cost and compact silicon-based detectors. We demonstrate the detection of wine spoilage based on excess gaseous acetic acid using peptide-wrapped SWCNT sensors down to 0.05% (v/v) acetic acid concentrations. Our results open new avenues for gas phase detection using NIR fluorescent SWCNT nanosensors.