Publications

Nanoparticle-based plasmonic optical fiber sensors can exhibit high sensing performance, in terms of refractive index sensitivities (RISs). However, a comprehensive understanding of the factors governing the RIS in this type of sensor remains limited, with existing reports often overlooking the presence of surface plasmon resonance (SPR) phenomena in nanoparticle (NP) assemblies and attributing high RIS to plasmonic coupling or waveguiding effects. Herein, using plasmonic optical fiber sensors based on spherical Au nanoparticles, we investigate the basis of their enhanced RIS, both experimentally and theoretically. The bulk behavior of assembled Au NPs on the optical fiber was investigated using an effective medium approximation (EMA), specifically the gradient effective medium approximation (GEMA). Our findings demonstrate that the Au-coated optical fibers can support the localized surface plasmon resonance (LSPR) as well as SPR in particular scenarios. Interestingly, we found that the nanoparticle sizes and surface coverage dictate which effect takes precedence in determining the RIS of the fiber. Experimental data, in line with numerical simulations, revealed that increasing the Au NP diameter from 20 to 90 nm (15% surface coverage) led to an RIS increase from 135 to 6998 nm/RIU due to a transition from LSPR to SPR behavior. Likewise, increasing the surface coverage of the fiber from 9% to 15% with 90 nm Au nanoparticles resulted in an increase in RIS from 1297 (LSPR) to 6998 nm/RIU (SPR). Hence, we ascribe the exceptional performance of these plasmonic optical fibers primary to SPR effects, as evidenced by the nonlinear RIS behavior. The outstanding RIS of these plasmonic optical fibers was further demonstrated in the detection of thrombin protein, achieving very low limits of detection. These findings support broader applications of high-performance NP-based plasmonic optical fiber sensors in areas such as biomedical diagnostics, environmental monitoring, and chemical analysis.

Chemometric analyses of near‐ (NIR) and middle‐infrared (mid‐IR) spectroscopy spectral data (12 500–4000 cm −1 and 4000–400 cm −1 ) by Partial Least Square (PLS) regression combined with analytical determination of polar phenolic compounds measured by HPLC in different varieties, geographical origin and marketplace categories olive oils—Protected Denomination of Origin (PDO) “Montes de Toledo”; Galician; high quality extra virgin (“Gourmet”/“Premium”); and commercial extra virgin and olive oils—were used to generate calibration and validation models in order to be able to predict the content and profile of these minor compounds, and thereby the quality of the product. Satisfactory multivariate test set validation algorithms were obtained for virgin olive oil (VOO)'s total polar phenolic (TPP) compounds ( r = 0.91), hydroxytyrosol and tyrosol secoiridoid derivatives (HtyrSec, TyrSec; r = 0.91 and 0.92, respectively). Contrary to NIRS, the chemometric analysis of the mid‐IR spectra gave no satisfactory validation models ( r = 0.43, 0.54, and 0.66 for HtyrSec, TyrSec, and TPP), despite that the calibration algorithms gave even higher correlation than NIRS ( r > 0.96 for all the polar phenolics studied). Practical applications: The results establish that NIRS is a very useful technique that allows rapid screening of VOO samples to estimate polar phenolic profile, and thereby their quality and commercial grade. Furthermore, it may give real time information about olive oil composition during processing in order to automatically control technological parameters. NIRS is a very useful technique that allows rapid screening of VOO samples to estimate polar phenolic profile, and thereby their quality and commercial grade.

Due to the benefits of antioxidant vitamins A, E and C, in the protection of the organism against free radicals, they are being increasingly used by the food industry to enrich foodstuffs, including a large variety of beverages. On the contrary than in USA or Japan, in Europe there are no specific regulations to control these products. This legal gap is contributing to the confusion of the consumers, producing problematic situations in some sectors of the population, such as in the case of pregnant women. According to nutritional labeling, this type of enriched products must reflect the nutritional properties. To verify whether these products fulfil the regulation in this study we checked labels in 16 samples, observing irregularities in the about 81% of the products. These irregularities are mainly: incorrect expressions of vitamin contents, omission of vitamin A proportions regarding RDAs, and deficiencies in the lowest level of vitamin C for enrichment. © 2001 Altaga. All rights reserved.

Natural compounds and their derivatives could be used for developing potent therapeutics with significant activity against SARS-COV-2, providing a promising frontline in the fighting against COVID-19.

Abstract BACKGROUND Many foods contain proteins and polyphenols, but there is a poor understanding of the nature of the inhibitory effect of protein on the biologic activity of polyphenols. The inhibitory mechanism of the food protein lactoferrin on the antibacterial activity of oligomeric ellagitannin oenothein B (OeB) was investigated using fluorescence quenching, isothermal titration calorimetry (ITC), circular dichroism (CD) measurement and molecular docking. RESULTS The antibacterial activity of OeB against Staphylococcus aureus was inhibited by lactoferrin, which was retained at about 60%. An interaction study revealed that an interaction occurred between OeB and lactoferrin. Thermodynamic analyses indicate that the binding process was spontaneous, and the main driving forces were based on electrostatic interactions that contributed to a high interaction affinity between OeB and lactoferrin. Furthermore, CD spectra provided insights into conformational changes of lactoferrin. Finally, molecular docking analysis provided a visual representation of a single binding site where OeB interacted with specific amino acid residues located at the active site of lactoferrin. In particular, due to the unique macrocyclic structure and rigid ring structure of OeB, a small number of hydroxyl groups in the rigid structure of OeB interacted with the amino acid of lactoferrin while most of the phenolic hydroxyl groups were not associated with lactoferrin. CONCLUSION Our study provides a theoretical basis for the use of OeB as an antibacterial substance that can be used in nutraceuticals and pharmaceutical products. © 2020 Society of Chemical Industry

<title>Abstract</title> <bold>Background</bold>: Since the COVID-19 outbreak an unprecedented challenge for healthcare systems around the world has been placed. In Cuba, the first case of COVID-19 was reported on March 11. Elderly with multiple comorbidities have been the most risky population. Although most patients present a mild to moderate disease, some have developed severe symptoms. One of the possible mechanisms underlying rapid disease progression is a cytokine storm, in which interleukin (IL) -6 seems to be a major mediator. Itolizumab is a humanized recombinant anti-CD6 monoclonal antibody (MAb), with the ability of reducing serum interferon gamma (INF-γ), tumour necrosis factor alpha (TNFα) and IL-6. Based on these previous results in patients with psoriasis and rheumatoid arthritis, an expanded access clinical trial was approved by the Cuban regulatory agency for COVID-19 critically, severely and moderately ill patients. <bold>Results</bold>: We show here a short kinetic of IL-6 serum concentration in the first 24 COVID-19 patients treated with itolizumab. Most of patients were elderly with multiple comorbidities. We found that with one itolizumab dose, the circulating IL-6 decreased in critically and severely ill patients, whereas in moderately ill patients the values didn’t rise as compared to their low baseline levels.<bold>Conclusion</bold>: These findings suggest that itolizumab could be an attractive therapeutic option to decrease the negative outcome of the cytokine storm in COVID-19 patients.<italic>Trial registration: CECMED IIC RD-EC 179, RPCEC00000311. Registered 4 May 2020 - Retrospectively registered, </italic><italic>http://rpcec.sld.cu/ensayos/RPCEC00000311-Sp</italic><italic> or </italic><italic>http://rpcec.sld.cu/trials/RPCEC00000311-En</italic>

Abstract The genomic diversity of circulating tumor cells (CTCs) and its clinical implications remain poorly understood. In this study, we characterized the mutational landscape of CTC pools stemming from 29 metastatic colorectal cancer (mCRC) patients and examined its relationship with disease progression. Our analysis revealed substantial variation in mutational burden among patients, with all CTC pools harboring non-silent mutations in key CRC driver genes. Importantly, higher genomic diversity in CTC pools was significantly associated with reduced overall survival. Furthermore, non-silent mutations in BCL9L emerged as a strong predictor of patient survival. Taken together, these findings underscore the potential of CTC genomic profiling as a promising prognostic tool in mCRC and highlight the need for further research into its clinical applications.

A novel hybrid plasmonic platform based on the synergetic combination of a molecularly imprinted polymer (MIP) thin film with Au nanoparticle (NPs) assemblies, noted as Au@MIP, was developed for surface-enhanced Raman scattering (SERS) spectroscopy recognition of polycyclic aromatic hydrocarbons (PAHs). While the MIP trapped the PAH close to the Au surface, the plasmonic NPs enhanced the molecule's Raman signal. The Au@MIP fabrication comprises a two-step procedure, first, the layer-by-layer deposition of Au NPs on glass and their further coating with a uniform MIP thin film. Profilometry analysis demonstrated that the thickness and homogeneity of the MIP film could be finely tailored by tuning different parameters such as prepolymerization time or spin-coating rate. Two different PAH molecules, pyrene or fluoranthene, were used as templates for the fabrication of pyrene- or fluoranthene-based Au@MIP substrates. The use of pyrene or fluoranthene, as the template molecule to fabricate the Au@MIP thin films, enabled its ultradetection in the nM regime with a 100-fold improvement compared with the nonimprinted plasmonic sensors (Au@NIPs). The SERS data analysis allowed to estimate the binding constant of the template molecule to the MIP. The selectivity of both pyrene- and fluoranthene-based Au@MIPs was analyzed against three PAHs of different sizes. The results displayed the important role of the template molecule used for the Au@MIPs fabrication in the selectivity of the system. Finally, the practical applicability of pyrene-based Au@MIPs was shown by performing the detection of pyrene in two real samples: creek water and seawater. The design and optimization of this type of plasmonic platform will pave the way for the detection of other relevant (bio)molecules in a broad range of fields such as environmental control, food safety, or biomedicine.