Optimisation of peptide nucleic acid (PNA) probe immobilisation by EIS for enhanced bioFET detection of miR-155

Lavecchia di Tocco, Francesco; Carrasco, Ivan Lopez; Beshchasna, Natalia; Cannistraro, Salvatore; Opitz, Joerg; Bizzarri, Anna Rita

doi:10.1016/j.microc.2025.115074

Optimisation of peptide nucleic acid (PNA) probe immobilisation by EIS for enhanced bioFET detection of miR-155

Author(s)

Lavecchia di Tocco, Francesco

Carrasco, Ivan Lopez

Beshchasna, Natalia

Cannistraro, Salvatore

Opitz, Joerg

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Date Issued

October 2025

Type

article

Volume

217

DOI

10.1016/j.microc.2025.115074

ISSN

0026-265X

Journal

MICROCHEMICAL JOURNAL

Abstract

MicroRNAs (miRNAs) are single-stranded oligonucleotides controlling gene expression whose deregulation is often linked to various human diseases, making them promising biomarkers. Electrochemical genosensors, particularly Field Effect Transistor-based biosensors (bioFETs), offer rapid, label-free methods for miRNA detection. These devices utilise capture probes capable of specifically recognising target miRNAs. Synthetic peptide nucleic acids (PNAs) exhibit high affinity for complementary strands, being then suitable for bioFETbased miRNA detection. The impact of the structural organisation of PNA-based self-assembled monolayers (SAMs) on the sensing performance of bioFETs, despite its critical importance, remains insufficiently understood and requires further investigations. The capture efficiency of PNA probes was optimised through its coimmobilisation with 6-mercapto-1-hexanol (MCH), a small diluent able to finely control the probe density and orientation. Electrochemical impedance spectroscopy (EIS) was employed to systematically characterise how MCH incorporation modulates the structural properties of the SAM and enhances hybridisation efficiency with microRNA-155. The optimised conditions for the PNA:MCH ratio were exploited to develop a custom-made bioFET setup for miRNA detection. We achieved a limit of detection (LoD) of (0.28 ± 0.06) pM with a 1000- fold improvement compared to our previous results. This bioFET platform also demonstrated a high specificity toward miR-155 combined with good recovery rate and reproducibility. The MCH-based surface optimisation strategy, integrated with bioFET technology, offers a simple and scalable solution for enhancing miRNA detection, and then contribu

Handle

https://dspace.unitus.it/handle/2067/63703

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