# Low-Cost Label-Free Electrochemical Aptasensor for Dual Detection of Dengue and Zika Using Fluorine-Doped Tin Oxide Modified with APTES and Gold Nanoparticles

## TL;DR

This paper presents a low-cost electrochemical sensor that can detect both dengue and zika viruses using modified fluorine-doped tin oxide and gold nanoparticles.

## Contribution

The novel contribution is a dual-detection electrochemical aptasensor for dengue and zika using cost-effective materials.

## Key findings

- The biosensor detected dengue with a limit of detection of 0.21 ng/mL in PBS and 0.55 ng/mL in human serum.
- Zika detection showed a limit of detection of 0.68 ng/mL in PBS, but nonlinear responses in serum.
- The sensor can detect both viruses in a single test but cannot distinguish between them.

## Abstract

The incidence of arbovirus infections, such as dengue
and zika,
has increased dramatically in recent decades, especially in tropical
regions and in technologically limited places. The goal of this study
is to create an affordable platform for both dengue and zika detection.
Fluorine-doped tin oxide-coated substrates were modified with APTES
and gold nanoparticles. The modified surfaces were functionalized
with the DNA aptamer and 6-mercapto-1-hexanol. Electrochemical impedance
spectroscopy was used to characterize and optimize aptasensors’
performance using nonstructural protein 1 (NS1) proteins as biomarkers.
The biosensor exhibited a limit of detection (LoD) of 0.21 ng/mL for
dengue in phosphate-buffered saline (PBS), with a sensitivity of 19.26%
per decade. In commercial human serum, the platform showed a signal
increase of 2% per decade, a LoD of 0.55 ng/mL, and a sensitivity
of 11.87% per decade. For zika detection, the biosensor presented
0.68 ng/mL LoD and a sensitivity of 26.34% per decade in PBS. In this
case, the presence of a biological matrix from commercial human serum
induced complex interaction with NS1, resulting in nonlinear sensor
responses. Although this platform was not able to distinguish between
zika and dengue infections, it enables the detection of both in a
single test, representing a promising approach for clinical diagnostics.