Plasma Functionalized Carbon Interfaces for Biosensor Application: Toward the Real-Time Detection of Escherichia coli O157: H7 .

Nonthermal plasma, a nondestructive, fast, and highly reproducible surface functionalization technique, was used to introduce desired functional groups onto the surface of carbon powder. The primary benefit is that it is highly scalable, with a high throughput, making it easily adaptable to bulk production. The plasma functionalized carbon powder was later used to create highly specific and low-cost electrochemical biosensors. The functional groups on the carbon surface were confirmed using NH 3 -temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) analysis. In addition, for biosensing applications, a novel, cost-effective, robust, and scalable electrochemical sensor platform comprising in-house-fabricated carbon paste electrodes and a miniaturized E-cell was developed. Biotin-Streptavidin was chosen as a model ligand-analyte combination to demonstrate its applicability toward biosensor application, and then, the specific identification of the target Escherchia coli O 157 :H 7 was accomplished using an anti- E. coli O 157 :H 7 antibody-modified electrode. The proposed biosensing platform detected E. coli O 157 :H 7 in a broad linear range of (1 × 10 -1 -1 × 10 6 ) CFU/mL, with a limit of detection (LOD) of 0.1 CFU/mL. In addition, the developed plasma functionalized carbon paste electrodes demonstrated high specificity for the target E. coli O 157 :H 7 spiked in pond water, making them ideal for real-time bacterial detection.