# Electrochemical Immunodetection of Bacillus anthracis Spores

## TL;DR

A new electrochemical biosensor can detect Bacillus anthracis spores quickly and with high accuracy, offering a portable and cost-effective alternative to traditional methods.

## Contribution

A novel thiol-modified gold electrode-based electrochemical method for sensitive and specific detection of Bacillus anthracis spores.

## Key findings

- The biosensor detects Bacillus anthracis spores at a limit of 103 CFU/mL.
- The method offers a sensitivity of 11 mV/log (CFU/mL) and requires minimal sample preparation.
- The system is portable, low-cost, and suitable for on-site diagnostics.

## Abstract

What are the main findings?
Electrochemical biosensor detects Bacillus anthracis in minutes with high selectivity.Novel thiol-modified gold electrodes enable sensitive and specific pathogen detection.Limit of detection reaches 103 CFU/mL, ensuring early anthrax spore identification.

Electrochemical biosensor detects Bacillus anthracis in minutes with high selectivity.

Novel thiol-modified gold electrodes enable sensitive and specific pathogen detection.

Limit of detection reaches 103 CFU/mL, ensuring early anthrax spore identification.

What is the implication of the main finding?
This portable, low-cost biosensor offers an alternative to PCR and ELISA in field settings.The method requires minimal sample preparation and is suitable for on-site diagnostics.

This portable, low-cost biosensor offers an alternative to PCR and ELISA in field settings.

The method requires minimal sample preparation and is suitable for on-site diagnostics.

The Centers for Disease Control and Prevention (CDC) classifies Bacillus anthracis as one of the most dangerous pathogens that may affect public health and national security. Due to its importance as a potential biological weapon, this bacteria has been classified in the highest category A, together with such pathogens as variola virus or botulinum neurotoxin. Characteristic features of this pathogen that increase its military importance are the ease of its cultivation, transport, and storage and its ability to create survival forms that are extremely resistant to environmental conditions. However, beyond bioterrorism, B. anthracis is also a naturally occurring pathogen. Anthrax outbreaks occur in livestock and wildlife, particularly in spore-contaminated regions of Africa, Asia, and North America. Spores persist for decades, leading to recurrent infections and zoonotic transmission through direct contact, inhalation, or consumption of contaminated meat. This work presents a new electrochemical method for detecting and quantifying B. anthracis in spore form using a selective immune reaction. The developed method is based on the thiol-modified electrodes that constitute the sensing element of the electrochemical system. Tests with the B. anthracis spore suspension showed that the detection limit for this pathogen is as low as 103 CFU/mL. Furthermore, it was possible to quantify the analyte with a sensitivity of 11 mV/log (CFU/mL). Due to several features, such as low unit cost, portability, and minimal apparatus demands, this method can be easily implemented in field analyzers for this pathogen and provides an alternative to currently used techniques and devices.