Lateral Flow Assay Biotesting by Utilizing Plasmonic Nanoparticles Made of Inexpensive Metals─Replacing Colloidal Gold.

Nanoparticles (NPs) can be conjugated with diverse biomolecules and employed in biosensing to detect target analytes in biological samples. This proven concept was primarily used during the COVID-19 pandemic with gold-NP-based lateral flow assays (LFAs). Considering the gold price and its worldwide depletion, here we show that novel plasmonic NPs based on inexpensive metals, titanium nitride (TiN) and copper covered with a gold shell (Cu@Au), perform comparable to or even better than gold nanoparticles. After conjugation, these novel nanoparticles provided high figures of merit for LFA testing, such as high signals and specificity and robust naked-eye signal recognition. Since the main cost of Au NPs in commercial testing kits is the colloidal synthesis, our development with the Cu@Au and the laser-ablation-fabricated TiN NPs is exciting, offering potentially inexpensive plasmonic nanomaterials for various bioapplications. Moreover, our machine learning study showed that biodetection with TiN is more accurate than that with Au.

Reshaping and induction of optical activity in gold@silver nanocuboids by chiral glutathione molecules.

Core-shell gold-silver cuboidal nanoparticles were produced, with either concave or straight facets. Their incubation with a low concentration of chiral l-glutathione (GSH) biomolecules was found to produce near UV plasmonic extinction and induced circular dichroism (CD) peaks. The effect is sensitive to the silver shell thickness. The GSH molecules were found to cause redistribution of silver in the shell, removing silver atoms from edges/corners and re-depositing them at the nanocuboid facets, probably through some redox and complexation processes between the silver and thiol group of the GSH. Other thiolated chiral biomolecules (and drug molecules) did not show this effect. The emerging near UV surface plasmon resonance is a silver slab resonance, which might also possess some multipolar resonance nature. The concave-shaped nanocuboids exhibited stronger induced plasmonic CD relative to the nanocuboids with straight facets.

Lateral Flow Assays Biotesting by Utilizing Plasmonic Nanoparticles Made of Inexpensive Metals - Replacing Colloidal Gold.

Nanoparticles (NPs) can be conjugated with diverse biomolecules and employed in biosensing to detect target analytes in biological samples. This proven concept was primarily used during the COVID-19 pandemic with gold NPs-based lateral flow assays (LFAs). Considering the gold price and its worldwide depletion, here we show that novel plasmonic nanoparticles (NPs) based on inexpensive metals, titanium nitride (TiN) and copper covered with a gold shell (Cu@Au), perform comparable or even better than gold nanoparticles. After conjugation, these novel nanoparticles provided high figures of merit for LFA testing, such as high signals and specificity and robust naked-eye signal recognition. To the best of our knowledge, our study represents the 1st application of laser-ablation-fabricated nanoparticles (TiN) in the LFA and dot-blot biotesting. Since the main cost of the Au NPs in commercial testing kits is in the colloidal synthesis, our development with TiN is very exciting, offering potentially very inexpensive plasmonic nanomaterials for various bio-testing applications. Moreover, our machine learning study showed that the bio-detection with TiN is more accurate than that with Au.

Local Photochemical Nanoscopy of Hot-Carrier-Driven Catalytic Reactions Using Plasmonic Nanosystems.

Nanoscale investigation of the reactivity of photocatalytic systems is crucial for their fundamental understanding and improving their design and applicability. Here, we present a photochemical nanoscopy technique that unlocks the local spatial detection of molecular products during plasmonic hot-carrier-driven photocatalytic reactions with nanometric precision. By applying the methodology to Au/TiO2 plasmonic photocatalysts, we experimentally and theoretically determined that smaller and denser Au nanoparticle arrays present lower optical contribution with quantum efficiency in hot-hole-driven photocatalysis closely related to the population heterogeneity. As expected, the highest quantum yield from a redox probe oxidation is achieved at the plasmon peak. Investigating a single plasmonic nanodiode, we unravel the areas where oxidation and reduction products are evolved with subwavelength resolution (∼200 nm), illustrating the bipolar behavior of such nanosystems. These results open the way to quantitative investigations at the nanoscale to evaluate the photocatalytic reactivity of low-dimensional materials in a variety of chemical reactions.

Onset of Chirality in Plasmonic Meta-Molecules and Dielectric Coupling.

Chirality is a fundamental feature in all domains of nature, ranging from particle physics over electromagnetism to chemistry and biology. Chiral objects lack a mirror plane and inversion symmetry and therefore cannot be spatially aligned with their mirrored counterpart, their enantiomer. Both natural molecules and artificial chiral nanostructures can be characterized by their light-matter interaction, which is reflected in circular dichroism (CD). Using DNA origami, we assemble model meta-molecules from multiple plasmonic nanoparticles, representing meta-atoms accurately positioned in space. This allows us to reconstruct piece by piece the impact of varying macromolecular geometries on their surrounding optical near fields. Next to the emergence of CD signatures in the instance that we architect a third dimension, we design and implement sign-flipping signals through addition or removal of single particles in the artificial molecules. Our data and theoretical modeling reveal the hitherto unrecognized phenomenon of chiral plasmonic-dielectric coupling, explaining the intricate electromagnetic interactions within hybrid DNA-based plasmonic nanostructures.

Clinical characteristics of pediatric patients with acute respiratory distress syndrome due to COVID-19.

BACKGROUND: There are only a few reports of acute respiratory distress syndrome (ARDS) in patients with SARS-CoV-2 in pediatrics. This study aimed to describe the characteristics of critically ill pediatric patients with COVID-19, the frequency of ARDS, ventilatory mechanics and results of prone position. METHODS: We conducted a retrospective, observational study of patients admitted to the pediatric intensive care unit (PICU) between April 1 to September 30, 2020. RESULTS: Thirty-four patients were admitted to pediatric intensive care unit, 31.7% were SARS-CoV-2 positive. 13 presented ARDS, 11 required invasive mechanical ventilation, and seven were pronated as an oxygenation strategy. All patients classified as severe ARDS were pronated. Obesity was the most important comorbidity. The complications associated with ARDS were multisystemic inflammatory syndrome (8 vs. 4; p < 0.05) and acute kidney injury (8 vs. 3; p < 0.05). Procalcitonin was higher in patients with ARDS, as were the days of stay in PICU (p < 0.05). The success of the pronation maneuver was achieved 8 hours later , with the following results: arterial oxygen partial pressure to fractional inspired oxygen ratio 128 vs. 204, oxygenation index 8.9 vs. 5.9, static lung compliance 0.54 vs. 0.70 ml/cmH2O/kg, plateau pressure 24 vs. 19 cmH2O (p < 0.05). The use of narcotics was higher in the group with ARDS plus pronation 124 vs. 27 hours in the non-pronated (p < 0.01). Mortality associated with SARS-CoV-2 was 5.8%. CONCLUSIONS: ARDS was presented in 38.2% of the children admitted to PICU and was more frequent in obese patients. Pronation, performed in severe cases, improved oxygenation and lung mechanics indexes. No patient died of ARDS.

INTRODUCCIÓN: Existen pocos reportes de síndrome de dificultad respiratoria aguda (SDRA) con COVID-19 en pacientes pediátricos. El objetivo de este estudio fue describir las características de los pacientes pediátricos críticamente enfermos con COVID-19, la frecuencia del SDRA, la mecánica ventilatoria y los resultados de la posición prona. MÉTODOS: Se llevó a cabo un estudio retrospectivo y observacional de los pacientes ingresados del 1 de abril al 30 de septiembre de 2020. RESULTADOS: Ingresaron 34 pacientes a la unidad de terapia intensiva pediátrica (UTIP) con prueba positiva para SARS-CoV-2. De ellos, 13 presentaron SDRA, 11 requirieron ventilación mecánica invasiva y siete fueron pronados como estrategia de oxigenación. Todos los pacientes clasificados como SDRA graves fueron pronados. La obesidad fue la comorbilidad más importante. Las complicaciones asociadas con SDRA fueron el síndrome inflamatorio multisistémico (p < 0.05) y la lesión renal aguda (p < 0.05). La procalcitonina fue mayor en los pacientes con SDRA, al igual que los días de estancia en la UTIP (p < 0.05). El éxito de la maniobra de pronación se alcanzó 8 horas después.Los resultados observados fueron los siguientes relación presión arterial de oxígeno/fracción inspirada de oxígeno 128 vs. 204, índice de oxigenación 8.9 vs. 5.9, distensibilidad pulmonar estática 0.54 vs. 0.70 ml/cmH2O/kg, y presión meseta 24 vs. 19 cmH2O (p < 0.05). El uso de narcóticos fue mayor en el grupo de SDRA más pronación que en los no pronados (124 vs. 27 h; p < 0.01). La mortalidad asociada con SARS-CoV-2 fue del 5.8%. CONCLUSIONES: El SDRA se presentó en el 38.2% de los niños admitidos a UTIP, y con mayor frecuencia en los pacientes con obesidad. La maniobra de pronación aplicada en los casos severos, mejoró la oxigenación de la mécanica pulmonar. Ninguno de los pacientes falleció por SDRA.

Características clínicas de pacientes pediátricos con síndrome de dificultad respiratoria aguda asociado con COVID-19 / Clinical characteristics of pediatric patients with acute respiratory distress syndrome due to COVID-19

Resumen Introducción: Existen pocos reportes de síndrome de dificultad respiratoria aguda (SDRA) con COVID-19 en pacientes pediátricos. El objetivo de este estudio fue describir las características de los pacientes pediátricos críticamente enfermos con COVID-19, la frecuencia del SDRA, la mecánica ventilatoria y los resultados de la posición prona. Métodos: Se llevó a cabo un estudio retrospectivo y observacional de los pacientes ingresados del 1 de abril al 30 de septiembre de 2020. Resultados: Ingresaron 34 pacientes a la unidad de terapia intensiva pediátrica (UTIP) con prueba positiva para SARS-CoV-2. De ellos, 13 presentaron SDRA, 11 requirieron ventilación mecánica invasiva y siete fueron pronados como estrategia de oxigenación. Todos los pacientes clasificados como SDRA graves fueron pronados. La obesidad fue la comorbilidad más importante. Las complicaciones asociadas con SDRA fueron el síndrome inflamatorio multisistémico (p < 0.05) y la lesión renal aguda (p < 0.05). La procalcitonina fue mayor en los pacientes con SDRA, al igual que los días de estancia en la UTIP (p < 0.05). El éxito de la maniobra de pronación se alcanzó 8 horas después.Los resultados observados fueron los siguientes relación presión arterial de oxígeno/fracción inspirada de oxígeno 128 vs. 204, índice de oxigenación 8.9 vs. 5.9, distensibilidad pulmonar estática 0.54 vs. 0.70 ml/cmH2O/kg, y presión meseta 24 vs. 19 cmH2O (p < 0.05). El uso de narcóticos fue mayor en el grupo de SDRA más pronación que en los no pronados (124 vs. 27 h; p < 0.01). La mortalidad asociada con SARS-CoV-2 fue del 5.8%. Conclusiones: El SDRA se presentó en el 38.2% de los niños admitidos a UTIP, y con mayor frecuencia en los pacientes con obesidad. La maniobra de pronación aplicada en los casos severos, mejoró la oxigenación de la mécanica pulmonar. Ninguno de los pacientes falleció por SDRA.

Abstract Background: There are only a few reports of acute respiratory distress syndrome (ARDS) in patients with SARS-CoV-2 in pediatrics. This study aimed to describe the characteristics of critically ill pediatric patients with COVID-19, the frequency of ARDS, ventilatory mechanics and results of prone position. Methods: We conducted a retrospective, observational study of patients admitted to the pediatric intensive care unit (PICU) between April 1 to September 30, 2020. Results: Thirty-four patients were admitted to pediatric intensive care unit, 31.7% were SARS-CoV-2 positive. 13 presented ARDS, 11 required invasive mechanical ventilation, and seven were pronated as an oxygenation strategy. All patients classified as severe ARDS were pronated. Obesity was the most important comorbidity. The complications associated with ARDS were multisystemic inflammatory syndrome (8 vs. 4; p < 0.05) and acute kidney injury (8 vs. 3; p < 0.05). Procalcitonin was higher in patients with ARDS, as were the days of stay in PICU (p < 0.05). The success of the pronation maneuver was achieved 8 hours later , with the following results: arterial oxygen partial pressure to fractional inspired oxygen ratio 128 vs. 204, oxygenation index 8.9 vs. 5.9, static lung compliance 0.54 vs. 0.70 ml/cmH2O/kg, plateau pressure 24 vs. 19 cmH2O (p < 0.05). The use of narcotics was higher in the group with ARDS plus pronation 124 vs. 27 hours in the non-pronated (p < 0.01). Mortality associated with SARS-CoV-2 was 5.8%. Conclusions: ARDS was presented in 38.2% of the children admitted to PICU and was more frequent in obese patients. Pronation, performed in severe cases, improved oxygenation and lung mechanics indexes. No patient died of ARDS.

Tolerability of IM penicillin G benzathine diluted or not with local anesthetics, or different gauge needles for syphilis treatment: a randomized clinical trial.

BACKGROUND: Penicillin G Benzathine (PGB) is the cornerstone of syphilis treatment. However, its intramuscular (IM) administration is associated with pain at the site of injection. The dilution of PGB with local anesthetics is recommended in some guidelines, but the evidence that supports it, particularly in adults and in HIV infection, is scarce. Preliminary clinical experience also suggests that the IM administration of PGB through increased needle gauges might improve its tolerability. The aim of the study to identify less painful ways of administering IM PGB in the treatment of syphilis in adults. METHODS: Multicenter, randomized, double-blinded clinical trial in patients diagnosed with primary syphilis that required a single IM injection of PGB 2400,00 IU. Patients were randomized to receive PGB diluted with 0.5 mL mepivacaine 1% (MV) or PGB alone, and both groups either with a long 19G or short 21G IM needle. The primary objective was the effect on local pain immediately after the administration through a visual scale questionnaire on pain (0 to 10). RESULTS: One hundred eight patients were included, 27 in each group. Ninety-four (94.4%) were male, and 41.7% were also HIV-infected. Mean age 36.6 years (SD 11). Significant differences in immediate pain intensity were observed when comparing the long 19G group with anesthesia (mean pain intensity, [MPI] 2.92 [CI 95% 1.08-4.07]) vs long 19G without anesthesia (MPI 5.56 [CI 95% 4.39-6.73), p < 0.001; and also between short 21G group with anesthesia (MPI 3.36 [CI 95% 2.22-4.50]) vs short 21G without anesthesia (MPI 5.06 [CI 95% 3.93-6.19]), p = 0.015). No significant differences in immediate pain were observed between 19G and 21G in the presence or absence of anesthesia (p = 1.0 in both cases). No differences were found between study arms after 6 and 24 h. CONCLUSIONS: The IM administration of 1% mepivacaine-diluted PGB induces significantly less immediate local pain as compared to PGB alone. The needle gauge did not have any effect on the pain. Based on these results, we suggest anesthetic-diluted IM PGB as the standard treatment for primary syphilis. TRIAL REGISTRATION: EudraCT 2014-003969-24 (Date of registration 18/09/2014).

Mediastinal myelolipoma with leukocytosis.

Myelolipoma is a benign tumour consisting of mature fat with scattered foci of haematopoietic elements resembling bone marrow. Extra-adrenal myelolipomas are an infrequent pattern of presentation. We report the case of a 64-year-old woman who presented a heterogeneous 1.4×2.5×3 cm paravertebral thoracic mass detected by chest tomography during the study of a leukocytosis of unknown aetiology. The CT findings and pathology revealed the diagnosis of myelolipoma.