Nanoparticle-enhanced surface plasmon resonance imaging: a powerful approach for the
ultrasensitive detection of nucleic acids
Giuseppe Spoto
Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, Catania, Italy
I.N.B.B. Consortium, Viale Delle Medaglie D’Oro 305, Roma, Italy
Email: gspoto@unict.it
Most of currently available methods for nucleic acids detection require sequences to be identified to
be previously amplified as well as labeled with fluorophores. Such procedures involve the use of
expensive reagents and pitfalls may occur due to contaminations or matrix effects. In addition, highspecificity and multiplexed capability are essential properties required for new devices to be used in
genomic DNAs and RNAs detection. Ultrasensitivity is also required in order to avoid the sample
PCR amplification.
Efforts have been recently made in identifying innovative and ultrasensitive DNA detection
protocols which can be performed without PCR.1 Most of them exploit strategies for signal
amplification based on the use of enzymes or metallic nanostructures. In particular, peculiar
chemical and physical properties of gold nanoparticles (AuNPs) have been used to obtain an
ultrasensitive DNA detection.2,3
Surface plasmon resonance imaging (SPRI) has emerged as a powerful optical method able to
investigate interactions with biomolecules arrayed onto chemically modified metal surfaces. SPRI
enables biomolecular interactions to be monitored in parallel, in real-time and without labels.4
Recently, we have demonstrated that the ultrasensitive detection of non-amplified genetically
modified organism soybean genomic DNA and SNPs in non-amplified human genomic DNAs
carrying the mutated β°39-globin gene sequence can be obtained by using a nanoparticle-enhanced
SPRI platform and peptide nucleic acid (PNA) probes.5,6 PNAs are DNA mimics in which the
negatively phosphate deoxyribose backbone is replaced by a neutral N-(2-aminoethyl)glycine
linkage. They have been shown to be able to improve both selectivity and sensitivity in targeting
complementary DNA and RNA sequences. Possibilities offered by the nanoparticle-enhanced SPRI
methods in microRNAs detection have been also investigated.
1. G. Spoto, R. Corradini [Eds.], Detection of Non-Amplified Genomic DNA, Dordrecht,
Springer, 2012.
2. L. M. Zanoli, R. D’Agata, G. Spoto. Functionalized gold nanoparticles for the ultrasensitive
DNA detection. Analytical and Bioanalytical Chemistry 402, 2012, 1759–1771.
3. G. Spoto, M. Minunni. Surface Plasmon Resonance imaging: What's next? The Journal of
Physical Chemistry Letters, 3, 2012, 2682−2691.
4. R. D’Agata, G. Spoto. Surface Plasmon Resonance Imaging for Nucleic Acid Detection.
Analytical and Bioanalytical Chemistry, 405(2-3), 2013, 573-584.
5. R. D’Agata, R. Corradini , C. Ferretti, L. Zanoli, M. Gatti, R. Marchelli, G. Spoto.
Ultrasensitive detection of non-amplified genomic DNA by nanoparticle-enhanced SurfacePlasmon Resonance Imaging. Biosensors and Bioelectronics 25, 2010,2095-2100.
6. R. D'Agata, G. Breveglieri, L.M. Zanoli, M. Borgatti, G. Spoto, R. Gambari. Direct Detection
of Point Mutations in Non-amplified Human Genomic DNA. Analytical Chemistry. 83(22),
2011, 8711-8717.