Ionic Strength Investigation on the Interaction Between miR-155 and a PNA-Based Probe by Atomic Force Spectroscopy
Author(s)
Date Issued
April 28, 2025
Type
article
Volume
15
Issue
5
ISSN
2218-273X
Journal
Abstract
Peptide nucleic acids (PNAs) are synthetic analogues of DNA/RNA characterized
by the absence of negative phosphate groups, which confer a low sensitivity to ionic
strength for hybridization with respect to the canonical counterpart. PNAs are a suitable
probe for miRNAs, as well as endogenous molecules of single-strand non-coding RNA
whose dysregulation is often linked to several diseases. The interaction forces between PNA
and microRNA-155 (miR-155), a multifunctional microRNA overexpressed in a variety of
tumors, were investigated by Atomic Force Spectroscopy (AFS) in fluid under different
conditions. We found that the unbinding forces acquired at the ionic strength of 150 mM
for a rather wide range of loading rates (ΔF/Δt) can be described using the Bell–Evans
model. This allows us to extract information on the kinetics and thermodynamic properties
of the miR-155/PNA duplex. Additionally, we probed the unbinding forces and the target
recognition times between miR-155 and PNA in the 50–300 mM ionic strength range. Our
results indicate that both of these parameters are practically independent from the ionic
strength in the analyzed range. The results provide information that is useful for a wider
use of PNA in biosensors for diagnostics and therapeutics, even in situ.
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biomolecules-15-00634-v2.pdf
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