# Evaluating Hybridization Chain Reaction to Improve miRNA Measurements at Portable Electroanalytical Strip: miRNA-21 as a Case of Study

## TL;DR

This paper introduces a cost-effective and portable method for measuring miRNA-21 using a hybridization chain reaction and a simple electrode, enabling quick and efficient detection for medical use.

## Contribution

The novel approach uses a hybridization chain reaction on a screen-printed electrode without complex modifications, enabling efficient miRNA detection.

## Key findings

- The system achieved a detection limit of approximately 100 pM for miRNA-21 in both standard and human serum samples.
- The method offers a cost-effective and sensitive solution for point-of-care diagnostics and real-time miRNA monitoring.

## Abstract

This work reports
on the evaluation of the hybridization
chain
reaction recognition system to be combined with a frugal sensing platform,
namely screen-printed electrode, for the measurement and the amplification
of circulating nucleic acids, without the use of time-consuming and
complex procedures. In fact, if traditional strategies usually rely
on nanomaterials or intricate modifications, our method places the
target sequence and hairpins directly on the electrode surface, reducing
both cost and preparation time while maintaining efficient signal
amplification. Two specific DNA-based hairpins, modified with methylene
blue as a redox mediator, has been rationally designed and characterized,
yielding a “signal-off” response triggered by the presence
of miRNA target. The system has been applied toward both standard
and human serum samples, obtaining satisfactory detection limit of
ca. 100 pM, with a repeatability less than 10%. This platform does
not require modification and/or complex work flow, it offers a cost-effective,
sensitive, and decentralized solution for point-of-care diagnostics
and real-time miRNA monitoring in clinical settings, not only for
cancer monitoring.