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Shavel A.,Catalonia Institute for Energy Research IREC | Shavel A.,Medcom Advance SA | Ibanez M.,Catalonia Institute for Energy Research IREC | Luo Z.,Catalonia Institute for Energy Research IREC | And 13 more authors.
Chemistry of Materials | Year: 2016

Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals (NCs), with quasi-spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%. © 2016 American Chemical Society.


PubMed | Medcom Advance S.A., Rovira i Virgili University, University of Bologna and Hospital Univesitario
Type: | Journal: Angewandte Chemie (International ed. in English) | Year: 2017

Point mutations in Ras oncogenes are routinely screened for diagnostics and treatment of tumors (especially in colorectal cancer). Here, we develop an optical approach based on direct SERS coupled with chemometrics for the study of the specific conformations that single-point mutations impose on a relatively large fragment of the K-Ras gene (141 nucleobases). Results obtained offer the unambiguous classification of different mutations providing a potentially useful insight for diagnostics and treatment of cancer in a sensitive, fast, direct and inexpensive manner.


Guerrini L.,Rovira i Virgili University | Guerrini L.,Medcom Advance SA | Arenal R.,University of Zaragoza | Mannini B.,University of Florence | And 6 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Protein misfolded proteins are among the most toxic endogenous species of macromolecules. These chemical entities are responsible for neurodegenerative disorders such as Alzheimer's, Parkinson's, Creutzfeldt-Jakob's and different non-neurophatic amyloidosis. Notably, these oligomers show a combination of marked heterogeneity and low abundance in body fluids, which have prevented a reliable detection by immunological methods so far. Herein we exploit the selectivity of proteins to react with metallic ions and the sensitivity of surface-enhanced Raman spectroscopy (SERS) toward small electronic changes in coordination compounds to design and engineer a reliable optical sensor for protein misfolded oligomers. Our strategy relies on the functionalization of Au nanoparticle-decorated polystyrene beads with an effective metallorganic Raman chemoreceptor, composed by Al3+ ions coordinated to 4-mercaptobenzoic acid (MBA) with high Raman cross-section, that selectively binds aberrant protein oligomers. The mechanical deformations of the MBA phenyl ring upon complexation with the oligomeric species are registered in its SERS spectrum and can be quantitatively correlated with the concentration of the target biomolecule. The SERS platform used here appears promising for future implementation of diagnostic tools of aberrant species associated with protein deposition diseases, including those with a strong social and economic impact, such as Alzheimer's and Parkinson's diseases. © 2015 American Chemical Society.


Tebbe M.,University of Bayreuth | Maennel M.,University of Bayreuth | Fery A.,University of Bayreuth | Pazos-Perez N.,University of Bayreuth | And 5 more authors.
Journal of Physical Chemistry C | Year: 2014

Gold nanorods are among the most efficient structures for optical applications, especially in surface-enhanced Raman scattering applications. Notably, their use directly in colloidal solutions decreases their optical enhancing properties because of the impossibility of generating hot spots and the passivation of their surfaces by the surfactants used during their preparation, hindering the interaction of the analyte with the plasmonic surface. We present an easy and fast method for preparing organized lying-down nanorod films with particles of different aspect ratios, yielding efficient and clean plasmonic films populated with a large number of homogeneous hot spots. © 2014 American Chemical Society.


Guerrini L.,Rovira i Virgili University | Guerrini L.,Medcom Advance SA | Krpetic Z.,University College Dublin | Krpetic Z.,University of Strathclyde | And 5 more authors.
Angewandte Chemie - International Edition | Year: 2015

The exploration of the genetic information carried by DNA has become a major scientific challenge. Routine DNA analysis, such as PCR, still suffers from important intrinsic limitations. Surface-enhanced Raman spectroscopy (SERS) has emerged as an outstanding opportunity for the development of DNA analysis, but its application to duplexes (dsDNA) has been largely hampered by reproducibility and/or sensitivity issues. A simple strategy is presented to perform ultrasensitive direct label-free analysis of unmodified dsDNA with the means of SERS by using positively charged silver colloids. Electrostatic adhesion of DNA promotes nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at nanogram level. As potential applications, we report the quantitative recognition of hybridization events as well as the first examples of SERS recognition of single base mismatches and base methylations (5-methylated cytosine and N6-methylated Adenine) in duplexes. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.


Romo-Herrera J.M.,National Autonomous University of Mexico | Gonzalez A.L.,Autonomous University of Puebla | Guerrini L.,Medcom Advance SA. | Castiello F.R.,National Autonomous University of Mexico | And 5 more authors.
Nanoscale | Year: 2016

High and uniform near fields are localized at the eight similar sharp corners of cubic gold nanoparticles. Moreover, by introducing concavity in the particle lateral planes, such field intensities can be further increased and tuned in the near infrared region without altering the overall size of the nanoparticles. Herein, we perform a thorough investigation of the morphological, crystallographic and plasmonic properties of concave gold nanocubes (GNCs) in the sub-70 nm size range, for their potential application as highly efficient SERS substrates in size-limiting cases. Theoretical calculations indicate that the highest increment of the near-field is located at the eight sharp tips and, interestingly, a medium near-field increment is also activated over the volume next to the concave surface. Remarkably, the plasmonic response of the concave cubic morphology showed great sensitivity to the concavity degree. Experimental SERS analysis nicely matches the outcome of the theoretical model, confirming that medium-sized concave GNCs (35 nm side length) possess the highest SERS activity upon excitation with a 633 nm laser, whereas larger 61 nm side concave GNCs dominate the optical response at 785 nm. Due to their size-intensity trade off, we envision that such small concave gold nanocubes can provide a highly active and efficient SERS platform for size-limiting applications, especially when near infrared excitations are required. © The Royal Society of Chemistry 2016.


Correa-Duarte M.A.,University of Vigo | Pazos Perez N.,Rovira i Virgili University | Pazos Perez N.,Medcom Advance SA | Guerrini L.,Rovira i Virgili University | And 5 more authors.
Journal of Physical Chemistry Letters | Year: 2015

A high-performance ionic-sensing platform has been developed by an interdisciplinary approach, combining the classical colorimetric Griess reaction and new concepts of nanotechnology, such as plasmonic coupling of nanoparticles and surface-enhanced Raman scattering (SERS) spectroscopy. This approach exploits the advantages of combined SERS/surface-enhanced resonant Raman Scattering (SERRS) by inducing the formation of homogeneous hot spots and a colored complex in resonance with the laser line, to yield detection limits for nitrite down to the subpicomolar level. The performance of this new method was compared with the classical Griess reaction and ionic chromatography showing detection limits about 6 and 3 orders of magnitude lower, respectively. © 2015 American Chemical Society.


Masetti M.,University of Bologna | Xie H.-N.,Medcom Advance SA | Krpetic Z.,University College Dublin | Recanatini M.,University of Bologna | And 5 more authors.
Journal of the American Chemical Society | Year: 2015

The standard protocols for DNA analysis largely involve polymerase chain reaction (PCR). However, DNA structures bound to chemical agents cannot be PCR-amplified, and therefore any sequence changes induced by external agents may be neglected. Thus, the development of analytical tools capable of characterizing the biochemical mechanisms associated with chemically induced DNA damage is demanded for the rational design of more effective chemotherapy drugs, understanding the mode of actions of carcinogenic chemicals, and monitoring the genotypic toxicology of environments. Here we report a fast, high-throughput, low-cost method for the characterization and quantitative recognition of DNA interactions with exogenous agents based on surface-enhanced Raman scattering spectroscopy. As representative chemical agents, we selected a chemotherapeutic drug (cisplatin) which forms covalent adducts with DNA, a duplex intercalating agent (methylene blue), and a cytotoxic metal ion (HgII) which inserts into T:T mismatches. Rich structural information on the DNA complex architecture and properties is provided by the unique changes of their SERS spectra, which also offer an efficient analytical tool to quantify the extent of such binding. © 2014 American Chemical Society.


PubMed | Medcom Advance S.A., Rovira i Virgili University, University of Santiago de Compostela and Hospital Universitario Hm Madrid Torrelodones
Type: Journal Article | Journal: Journal of the American Chemical Society | Year: 2016

Blood-based biomarkers (liquid biopsy) offer extremely valuable tools for the noninvasive diagnosis and monitoring of tumors. The protein c-MYC, a transcription factor that has been shown to be deregulated in up to 70% of human cancers, can be used as a robust proteomic signature for cancer. Herein, we developed a rapid, highly specific, and sensitive surface-enhanced Raman scattering (SERS) assay for the quantification of c-MYC in real blood samples. The sensing scheme relies on the use of specifically designed hybrid plasmonic materials and their bioderivatization with a selective peptidic receptor modified with a SERS transducer. Peptide/c-MYC recognition events translate into measurable alterations of the SERS spectra associated with a molecular reorientation of the transducer, in agreement with the surface selection rules. The efficiency of the sensor is demonstrated in cellular lines, healthy donors and a cancer patient.


PubMed | Medcom Advance SA., Rovira i Virgili University, National Autonomous University of Mexico and Autonomous University of Puebla
Type: Journal Article | Journal: Nanoscale | Year: 2016

High and uniform near fields are localized at the eight similar sharp corners of cubic gold nanoparticles. Moreover, by introducing concavity in the particle lateral planes, such field intensities can be further increased and tuned in the near infrared region without altering the overall size of the nanoparticles. Herein, we perform a thorough investigation of the morphological, crystallographic and plasmonic properties of concave gold nanocubes (GNCs) in the sub-70 nm size range, for their potential application as highly efficient SERS substrates in size-limiting cases. Theoretical calculations indicate that the highest increment of the near-field is located at the eight sharp tips and, interestingly, a medium near-field increment is also activated over the volume next to the concave surface. Remarkably, the plasmonic response of the concave cubic morphology showed great sensitivity to the concavity degree. Experimental SERS analysis nicely matches the outcome of the theoretical model, confirming that medium-sized concave GNCs (35 nm side length) possess the highest SERS activity upon excitation with a 633 nm laser, whereas larger 61 nm side concave GNCs dominate the optical response at 785 nm. Due to their size-intensity trade off, we envision that such small concave gold nanocubes can provide a highly active and efficient SERS platform for size-limiting applications, especially when near infrared excitations are required.

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