Publications

We describe a simple and efficient methodology for the aqueous synthesis of stable, uniform, and size tunable Au@Ag core-shell nanoparticles (NPs) that are stabilized by citrate ions. The synthetic route is based on the stepwise Ag reduction on preformed Au NPs. The final size of the core-shell NPs and therefore their optical properties can be modulated at least from 30 to 110 nm by either tuning the Ag shell thickness or changing the size of the Au core. The optical properties of the Au@Ag core-shell NPs resemble those of pure Ag NPs of similar sizes, which was confirmed by means of Mie extinction calculations. We additionally evaluated the surface-enhanced raman scattering (SERS) enhancing properties of Au@Ag core-shell NP colloids with three different laser lines (532, 633, and 785 nm). Importantly, such core-shell NPs also exhibit a higher SERS efficiency than Ag NPs of similar size under near-infrared excitation. The results obtained here serve as a basis to select Au@Ag core-shell NPs of specific size and composition with maximum SERS efficiency at their respective excitation wavelengths for SERS-based analytical and bioimaging applications.

[This corrects the article DOI: 10.1371/journal.pone.0173003.].

We report on the first realization of a hyperspectral imaging (HSI) technique of surface plasmon polaritons excited in metallic nanostructures by a scanning electron beam. The HSI image is formed by scanning a plasmonic structure with a focused electron beam, simultaneously recording the spectra of light emission from decoupled plasmons by a spectrum analyzer. By scanning the sample in this manner, one obtains a data cube consisting of the spatial coordinates of the position of the injected electron beam and the corresponding plasmon emission spectra.

In recent years, consumers have been increasingly interested in natural, healthier, functional foods, with a focus on sea-based products such as algae. Bifurcaria bifurcata (BB) is a macroalga that belongs to the Phaeophyceae class. These brown algae are recognized as the source of bioactive molecules of great interest to the pharmaceutical and nutraceutical industries. The present work applied response surface methodology to optimize the microwave-assisted extraction of the poorly studied algae. The optimization variables were time, pressure, and solvent composition (ethanol/water) and the response parameters selected were yield, total phenolic and flavonoid content, and the antioxidant profile by evaluating DPPH•+, ABTS•+ scavenging activity, and β-carotene discoloration capacity. The results obtained reveal remarkable bioactivity of the crude extract of BB with positive results as an antioxidant and antimicrobial agent. Furthermore, the BB extract’s capacity to inhibit enzymes related to neurodegenerative diseases and its anti-inflammatory and anti-proliferation activity open the possibility of future food or pharmaceutical applications.

Abstract Rationale: Blue rubber bleb nevus syndrome (BRBNS) is an extremely rare disorder characterized by multifocal venous malformations involving various organs such as the skin and gastrointestinal tract. Severe complications of BRBNS, such as intussusception, volvulus, and intestinal infarction are rarer and require surgery. This report describes a 33-year-old male of BRBNS complicated with intussusception that was successfully diagnosed and treated with surgery. Patient concerns: A 33-year-old Chinese man presented with persistent, colicky pain accompanied by nausea, abdominal distension, and dizziness. The patient presented with sporadic bluish nodules on his skin involving his head, neck, thorax, abdomen, and planta pedis. Diagnoses: BRBNS with the complication of intussusception. Interventions: An emergency laparotomy was performed, and postoperative management included blood transfusions and oral iron supplementation for 2 weeks. Outcomes: The patient's postoperative course of hospitalization was uneventful. During the 4-month follow-up, the patient showed no signs of intussusception recurrence. Lessons: Patients diagnosed with BRBNS who present with acute abdominal pain and distension should raise suspicion for the presence of intussusception, which requires emergent surgical intervention.

The use of statins in the field of bone regeneration is under current investigation due to the existing demand for non-toxic anabolic agents capable of enhancing bone formation in cases of substantial loss. Simvastatin, a coenzyme currently prescribed in clinics to inhibit cholesterol biosynthesis, has been proven to promote osteogenic differentiation by stimulating bone formation and inhibiting osteoclasts activity. We present the loading of simvastatin in mesoporous TiO₂ thin films toward combining the pro-osteogenic properties of this molecule with the demonstrated bioactivity of titania. TiO₂ thin films processing and characterization were carried out, as well as evaluation of MC3T3-E1 pre-osteoblasts viability when directly incubated with different concentrations of simvastatin, followed by the analysis of osteogenic activity promoted by simvastatin upon loading in the thin films. The accessible porosity of 36% quantified on the 95 ± 5 nm thick mesoporous thin films, together with pore diameters of 5.5 nm, necks between pores of 2.8 nm and interpore distances of 12 ± 2 nm allow the loading of the simvastatin molecule, as confirmed by FTIR spectroscopy. Simvastatin was found to promote MC3T3-E1 pre-osteoblasts viability at concentrations ≤0.01 g l^-1, with a cytotoxicity threshold of 0.05 g l^-1. We additionally found that film loadings with 0.001 g l^-1 simvastatin promotes statistically higher MC3T3-E1 pre-osteoblast proliferation whereas a higher concentration of 0.01 g l^-1 leads to statistically higher osteogenic activity (ALP synthesis), after 21 days of incubation, as compared to unloaded films. These results demonstrate the potential of simvastatin local administration based on bioactive mesoporous thin films to promote pro-osteogenic properties. By focusing this strategy on the coating of metallic prostheses, the supply of simvastatin to the target tissue can be favored and risks of systemic side effects will be reduced while enhancing the osteointegration of the implants.