A Carbon Nanotube Immunosensor for Salmonella

TL;DR

This study demonstrates a carbon nanotube-based immunosensor capable of specifically detecting Salmonella bacteria in complex solutions, with potential for integration into large-scale food safety monitoring systems.

Contribution

The paper reports the development of a nanotube transistor immunosensor that specifically detects Salmonella with high sensitivity and demonstrates its potential for scalable food safety applications.

Findings

Sensitive detection of Salmonella at concentrations below 1000 cfu/ml.

Carrier mobility is affected by various bacteria without saturation.

Device size is suitable for large-scale array integration.

Abstract

Antibody-functionalized carbon nanotube devices have been suggested for use as bacterial detectors for monitoring of food purity in transit from the farm to the kitchen. Here we report progress towards that goal by demonstrating specific detection of Salmonella in complex nutrient broth solutions using nanotube transistors functionalized with covalently-bound anti-Salmonella antibodies. The small size of the active device region makes them compatible with integration in large-scale arrays. We find that the on-state current of the transistor is sensitive specifically to the Salmonella concentration and saturates at low concentration (<1000 cfu/ml). In contrast, the carrier mobility is affected comparably by Salmonella and other bacteria types, with no sign of saturation even at much larger concentrations (10^8 cfu/ml).