ac8b04052_si_001.pdf (336.32 kB)
Paper-Based Strips for the Electrochemical Detection of Single and Double Stranded DNA
journal contribution
posted on 2018-10-19, 00:00 authored by Stefano Cinti, Elena Proietti, Federica Casotto, Danila Moscone, Fabiana ArduiniThe
detection of double stranded DNA (dsDNA) is often associated
with the use of laboratory-bound approaches and/or with the prior
generation of single stranded DNA (ssDNA), making these methods not
suitable for in situ monitoring, i.e., point-of-care diagnostics.
Screen-printed technology, coupled to the use of triplex forming oligonucleotides
(TFO) as the recognizing probes, offers a great possibility toward
the development of portable analytical tools. Moreover, the continuous
demand for sustainable processes and waste lowering have highlighted
the role of paper-based substrates for manufacturing easy-to-use,
low-cost, and sustainable electrochemical devices. In this work, filter
paper and copy paper have been utilized to produce E-DNA strips. Gold
nanoparticles (AuNPs) have been exploited to immobilize the methylene
blue (MB)-tagged TFO and to enhance the charge transfer kinetics at
the electrode surface. Both paper-based substrates have been electrochemically
characterized, and in addition, the effect of the amount of waxed
layers has been evaluated. The paper-based E-DNA strips have been
challenged toward the detection of three model targets, obtaining
3 and 7 nM as the detection limit, respectively, for single and double
stranded sequences. The repeatability of the manufacturing (homemade)
process has been evaluated with a relative standard deviation of approximately
10%. The effectiveness of the filter paper-based platform has been
also evaluated in undiluted serum obtaining a similar value of the
detection limit (compared to the measurements carried out in buffer
solution). In addition, a synthetic PCR amplified dsDNA sequence,
related to HIV, has been detected in serum samples.