ABSTRACT
The aim of this work was to study the biophysical properties of the chitosan-grafted poly(lactic acid) (CH-g-PLA) nanofibers loaded with silver nanoparticles (AgNPs) and chondroitin-4-sulfate (C4S). The electrospun CH-g-PLA:AgNP:C4S nanofibers were manufactured using the electrospinning technique. The microstructure of the CH-g-PLA:AgNP:C4S nanofibers was investigated by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Fourier transform infrared (ATR-FTIR) spectroscopy. ATR-FTIR and 1H-NMR confirm the CH grafting successfully by PLA with a substitution degree of 33.4%. The SEM measurement results indicated apparently smooth nanofibers having a diameter range of 340 ± 18 nm with porosity of 89 ± 3.08% and an average pore area of 0.27 µm2. UV-Vis and XRD suggest that silver nanoparticles with the size distribution of 30 nm were successfully incorporated into the electrospun nanofibers. The water contact angle of 12.8 ± 2.7° reveals the hydrophilic nature of the CH-g-PLA:AgNP:C4S nanofibers has been improved by C4S. The electrospun CH-g-PLA:AgNP:C4S nanofibers are found to release ions Ag+ at a concentration level capable of rendering an antimicrobial efficacy. Gram-positive bacteria (S.aureus) were more sensitive to CH-g-PLA:AgNP:C4S than Gram-negative bacteria (E. coli). The electrospun CH-g-PLA:AgNP:C4S nanofibers exhibited no cytotoxicity to the L-929 fibroblast cells, suggesting cytocompatibility. Fluorescence microscopy demonstrated that C4S promotes the adhesion and proliferation of fibroblast cells onto electrospun CH-g-PLA:AgNP:C4S nanofibers.
Subject(s)
Chitosan , Metal Nanoparticles , Nanofibers , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Chitosan/chemistry , Chondroitin Sulfates , Escherichia coli , Metal Nanoparticles/chemistry , Nanofibers/chemistry , Polyesters/chemistry , Silver/chemistry , Silver/pharmacologyABSTRACT
Desde el 70 al 80 Aniversario de la fundación del Instituto de Medicina Tropical "Pedro Kourí", los investigadores, profesionales y técnicos de este centro, han laborado en cooperación con diversas instituciones académicas y de los servicios de salud de Cuba (en equipos multidisciplinarios) en las tareas de desarrollo científico, innovación tecnológica y construcción de capacidades. Este artículo resume las principales investigaciones realizadas sobre la tuberculosis desde 2008-2017; como contribuciones al Programa Nacional de Control y Eliminación de la Tuberculosis con la perspectiva de aumentar la calidad, efectividad y eficiencia de las acciones y acelerar la solución de la incidencia y la mortalidad por tuberculosis, para la investigación, la vigilancia y control de la tuberculosis. Se presentan evidencias que fundamentan las innovaciones en el manejo clínico terapéutico de pacientes inmunocompetentes e inmunocomprometidos, en niños y adolescentes, sobre las indicaciones para el control de la infección tuberculosa latente, la vigilancia de los desenlaces del tratamiento anti-tuberculosis, la investigación de contactos de casos, los cambios en el sistema de registro e información, el monitoreo y evaluación de la calidad de la detección de casos de tuberculosis, el impacto sobre la morbilidad y la mortalidad.
During the period extending from the 70th to the 80th anniversary of the founding of Pedro Kouri Tropical Medicine Institute, researchers, professionals and technicians from the center, in joint cooperation with a variety of Cuban academic and health care institutions, have integrated into multidisciplinary teams engaged in tasks related to scientific development, technological innovation and capacity building. The paper summarizes the main research studies about tuberculosis conducted from 2008 to 2017 as contributions to the National Tuberculosis Control and Elimination Program, with a view to enhancing the quality, effectiveness and efficiency of actions, swiftly finding a solution to tuberculosis incidence and mortality, and fostering tuberculosis research, surveillance and control. Evidence is presented which substantiates innovations in the clinical therapeutic management of both immunocompetent and immunocompromised patients, children and adolescents, and indications are provided for latent tuberculosis infection control, surveillance of anti-tuberculosis treatment outcomes, investigation of case contacts, changes in the record and information system, quality monitoring and evaluation of the detection of tuberculosis cases, and impact on morbidity and mortality.
