Integrating Plasmonic Supercrystals in Microfluidics for Ultrasensitive, Label-Free, and Selective Surface-Enhanced Raman Spectroscopy Detection.

Surface-enhanced Raman spectroscopy (SERS) microfluidic chips for label-free and ultrasensitive detection are fabricated by integrating a plasmonic supercrystal within microfluidic channels. This plasmonic platform allows the uniform infiltration of the analytes within the supercrystal, reaching the so-called hot spots. Moreover, state-of-the-art simulations performed using large-scale supercrystal models demonstrate that the excellent SERS response is due to the hierarchical nanoparticle organization, the interparticle separation (IPS), and the presence of supercrystal defects. Proof-of-concept experiments confirm the outstanding performance of the microfluidic chips for the ultradetection of (bio)molecules with no metal affinity. In fact, a limit of detection (LOD) as low as 10-19 M was reached for crystal violet. The SERS microfluidic chips show excellent sensitivity in the direct analysis of pyocyanin secreted by Pseudomonas aeruginosa grown in a liquid culture medium. Finally, the further integration of a silica-based column in the plasmonic microchip provides charge-selective SERS capabilities as demonstrated for a mixture of positively and negatively charged molecules.

Identificación de &-talasemia en anemias microcíticas hipocrómicas refractarias al tratamiento con hierro en Nicaragua / Identification of &-thalassemia in hypochromic microcytic anemias refractory to iron treatment in Nicaragua

Resumen Justificación y objetivo: gran parte de los casos descritos de anemias microcíticas-hipocrómicas corresponden a anemias ferropénicas y síndromes talasémicos. El diagnóstico diferencial se complementa con pruebas de laboratorio como el hierro sérico, ferritina, entre otras; sin embargo, estas son de baja disponibilidad en países en vías de desarrollo. En Nicaragua, el diagnóstico de estas patologías se basa en el historial clínico y análisis hematológicos de rutina. El objetivo de este trabajo fue la implementación de la técnica de cuantificación de hemoglobina A2 en el diagnóstico clínico de β-talasemia. Métodos: se realizó un estudio transversal con 30 pacientes que mostraban microcitosis e hipocromía después de 3 meses de tratamiento con sales de hierro. Se realizó electroforesis de hemoglobina y se utilizó el kit de la casa comercial Beta-Thal HbA2 Quik Column para cuantificar la hemoglobina A2 en cada paciente. El análisis estadístico utilizado fue la prueba de t de student. Se consideraron significativas las diferencias a p<0,05. Esta investigación respetó los principios éticos que conciernen. Se contó con la aprobación del Comité de Ética Institucional, UNAN-Managua. Los participantes dieron su consentimiento informado. Resultados: al aplicar el método para cuantificación de hemoglobina A2, se obtuvo que el 67 % de las muestras presentaron una concentración de hemoglobina A2 mayor al valor de referencia establecido (3,3 %), siendo pacientes diagnosticados para β-talasemia menor. El 33 % restante presentó valores normales de hemoglobina A2 con microcitosis e hipocromía. Se encontraron diferencias estadísticamente significativas entre las medias de glóbulos rojos, volumen corpuscular medio, hemoglobina corpuscular media y hemoglobina A2, entre ambos grupos. Conclusión: el diagnóstico diferencial de anemias microcíticas hipocrómicas refractarias al tratamiento con hierro, se realiza inicialmente por el historial clínico del paciente, pero es necesario contar con pruebas diagnósticas como la cuantificación de hemoglobina A2 que permitan identificar las diversas patologías que cursan con microcitosis e hipocromía.

Abstract Justification and objective: much of the described cases of microcytic-hypochromic anemias are ferropenic anemias and Thalassemia syndromes. The differential diagnosis is complemented by laboratory tests as serum iron, ferritin, among others; However, these are of low availability in developing countries. In Nicaragua, the diagnosis of these diseases is based on clinical history and routine blood analysis. The objective of this work was to implement a technique for quantification of hemoglobin A2 in the clinical diagnosis of β-Thalassemia. Methods: We conducted a cross-sectional study with 30 patients showing hypochromia and microcytosis after 3 months of treatment with iron salts. Hemoglobin electrophoresis was performed, a kit from Beta-Thal HbA2 Quik Column was used to quantify the hemoglobin A2 in each patient. The statistical analysis used was the student's t test. The differences were considered significant at p < 0.05. This research respected ethical principles that concern. It had the approval of the committee of ethics institutional, UNAN-Managua and the participants gave their informed consent. Results: when applying the method for quantification of hemoglobin A2, 67% of samples presented a concentration of hemoglobin A2 greater than the reference value set at 3.3%, these patients were diagnosed with β-Thalassemia minor. The remaining 33% presented normal values of hemoglobin A2 with hypochromia and microcytosis. Statistically significant differences between the averages of red blood cells, mean corpuscular volume, mean corpuscular hemoglobin and hemoglobin A2 between the two groups was observed. Conclusion: The differential diagnosis of microcytic hypochromic anemias refractory to treatment with iron, is initially performed by the clinical history of the patient, but it is necessary to have diagnostic tests such as the quantification of hemoglobin A2, which allow the identification of patients with β-Thalassemia minor within this group. In our study 67% of the studied samples were identified as β-Thalassemia minor.

Structural characterization of the N-glycosylation of individual soybean ß-conglycinin subunits.

Soybean (Glycine max) 7S ß-conglycinin is a seed storage protein consisting of homo- and hetero-trimers of three subunits, namely α (~67 kDa), α' (~71 kDa), and ß (~50 kDa), non-covalently associated. The N-glycans released from the whole ß-conglycinin have been already characterized by (1)H NMR some decades ago. Nevertheless, the actual glycosylation of the potential sites and the glycoforms of the individual subunits have not been specifically investigated so far. In this study, up-to-date chromatographic, electrophoretic and mass spectrometric strategies have been combined to achieve the structural characterization of the glycoforms of the three individual ß-conglycinin subunits. Glycosylation sites were assigned by analyzing the tryptic glycopeptides of the isolated subunits. Underivatized N-glycans were purified with a two-step clean-up, consisting in sequential reversed-phase and activated porous graphitized carbon micro-chromatography, and profiled by matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS).