Metallic nanoparticles are very interesting because of their potential use in microelectronics, optical devices, biomedical and sensing applications. Their individual electromagnetic response is highly dependent on the specific size, shape, and surrounding environment. Nowadays, there are different methods which allow us to fine tune these parameters and thus, the materials properties. On the other hand, surface enhance Raman scattering (SERS) spectroscopy is a powerful ultra-sensitive technique which allows detection down to single molecule levels. However, the production of effective and highly active SERS substrates is mainly based on the generation of hot spots created by plasmonic nanoparticles. Nonetheless, the lack of capability to form reproducible organized structures at large scales is still a very important challenge to solve in order to produce substrates with homogeneous and reproducible SERS intensities over large areas. In this work, we report novel methods to produce arrays of nanoparticles, either as continuous or as isolated super-crystals made with plasmonic nanoparticles.[1] These macro-scale organizations were created via confinement controlled drying and spin coating. SERS studies on the super-crystals shape and size were conducted. Moreover, the produced structures were effectively use for SERS sensing showing very good reproducibility among big areas. This fact, make them perfect candidates as ultrasensitive substrates for SERS due to the controlled formation of hot spots. Which provide high and uniform SERS enhancement over extended areas.
[1] Nanoscale. 2016, 8 12702
Recently, plasmonic-based biosensing has experienced an unprecedented level of attention, with a particular focus on the nucleic acid detection, offering efficient solutions to engineer simple, fast, highly sensitive sensing platforms while overcoming important limitations of PCR and microarray techniques. In the broad field of plasmonics, surface-enhanced Raman scattering (SERS) spectroscopy has arisen as a powerful analytical tool for detection and structural characterization of biomolecules. Today applications of SERS to nucleic acid analysis largely rely on indirect strategies, which have been demonstrated very effective for pure sensing purposes but completely dismiss the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. Contrarily, direct label-free SERS of nucleic acid shows an outstanding potential in terms of chemical-specific information which, however, remained largely unexpressed mainly because of the inherent poor spectral reproducibility and/or limited sensitivity.
To address these limitations, we developed a fast and affordable high-throughput screening direct SERS method for gaining detailed genomic information on nucleic acids (DNA and RNA) and for the characterization and quantitative recognition of DNA interactions with exogenous agents. The simple strategy relies on the electrostatic adhesion of DNA/RNA onto positively-charged silver colloids that promotes the nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at picogram level (i.e. the analysis can be performed without the necessity of amplification steps thus providing realistic direct information of the nucleic acid in its native state). We anticipate this method to gain a vast impact and set of applications in different fields, including medical diagnostics, genomic screening, drug discovery, forensic science and even molecular electronics.
Conference Committee Involvement (8)
Colloidal Nanoparticles for Biomedical Applications XVII
22 January 2022 | San Francisco, California, United States
Colloidal Nanoparticles for Biomedical Applications XVI
6 March 2021 | Online Only, California, United States
Colloidal Nanoparticles for Biomedical Applications XV
1 February 2020 | San Francisco, California, United States
Colloidal Nanoparticles for Biomedical Applications XIV
2 February 2019 | San Francisco, California, United States
Colloidal Nanoparticles for Biomedical Applications XIII
27 January 2018 | San Francisco, California, United States
Colloidal Nanoparticles for Biomedical Applications XII
28 January 2017 | San Francisco, California, United States
Colloidal Nanoparticles for Biomedical Applications XI
13 February 2016 | San Francisco, California, United States
Colloidal Nanoparticles for Biomedical Applications X
7 February 2015 | San Francisco, California, United States
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