# An Eco-Friendly Disposable Plasmonic Biochip Based on Bacterial Cellulose for Interleukin-17A Detection at Atto-Femto Molar Level

## TL;DR

A biodegradable, low-cost biochip made from bacterial cellulose can detect very low levels of a key immune protein, making it useful for portable medical tests.

## Contribution

Development of an eco-friendly, gold-coated bacterial cellulose biochip with atto-femto molar sensitivity for IL-17A detection.

## Key findings

- The BC-based LSPR chip achieved a bulk sensitivity of 370 nm/RIU.
- The biochip detected IL-17A at a detection limit of approximately 400 aM.
- The chip showed good selectivity toward other interleukins.

## Abstract

The need for disposable, low-cost, biodegradable, small-size,
and
biocompatible sensor chips is crucial for the development of point-of-care
tests (POCTs) in several bio/chemical sensing application fields.
In this scenario, an eco-friendly sensor chip based on gold-coated
bacterial cellulose (BC) nanostructures, which exploits localized
surface plasmon resonance (LSPR) phenomena, is combined with a bioreceptor
layer as a proof-of-concept for cytokine detection. The BC-based LSPR
chip was developed and tested using a simple transmission-based experimental
setup, enabling both bulk and binding sensitivity characterization.
In particular, the optical analysis revealed a BC-based LSPR chip’s
bulk sensitivity of about 370 nm/RIU, comparable to that of more complex
and expensive LSPR platforms reported in the literature. Following
a functionalization process with an antibody specific for the interleukin
17A (IL-17A) protein, the BC-based LSPR biochip was tested, demonstrating
an ultralow detection limit in the atto-femto molar range (detection
limit of approximately 400 aM), an ultrawide detection range, and
good selectivity toward other interleukins, making it a proof-of-principle
useful in biomedical applications. The achieved results paved the
way for the applicability of this eco-friendly biochip as a disposable
chip useful for POCTs in several application fields, where the required
disposable feature is due to contamination that occurs during measurements
in real-world scenarios.