Hybrid 1D Plasmonic/Photonic Crystals are Responsive to Escherichia Coli

TL;DR

This paper introduces a hybrid plasmonic/photonic biosensor responsive to Escherichia coli, utilizing a silver layer on a photonic crystal to detect bacterial contamination through dielectric property changes, enabling low-cost, portable detection.

Contribution

The work presents a novel hybrid plasmonic/photonic device that detects E. coli via dielectric modifications, combining plasmonic and photonic features for biosensing.

Findings

Blue-shift in photonic response upon bacterial detection

Silver layer's dielectric change correlates with bacterial presence

Device offers a low-cost, portable detection platform

Abstract

Photonic crystal-based biosensors hold great promise as valid and low-cost devices for real-time monitoring of a variety of biotargets. Given the high processability and easiness of read-out even for unskilled operators, these systems can be highly appealing for the detection of bacterial contaminants in food and water. Here, we propose a novel hybrid plasmonic/photonic device that is responsive to Escherichia coli, which is one of the most hazardous pathogenic bacterium. Our system consists of a thin layer of silver, a metal that exhibits both a plasmonic behavior and a well-known biocidal activity, on top of a solution processed 1D photonic crystal. We attribute the bio-responsivity to the modification of the dielectric properties of the silver film upon bacterial contamination, an effect that likely stems from the formation of polarization charges at the Ag/bacterium interface within a sort of bio-doping mechanism. Interestingly, this triggers a blue-shift in the photonic response. This work demonstrates that our hybrid plasmonic/photonic device can be a low-cost and portable platform for the detection of common contaminants in food and water.