Size-controlled and redox-responsive supramolecular nanoparticles

Control over the assembly and disassembly of nanoparticles is pivotal for their use as drug delivery vehicles. Here, we aim to form supramolecular nanoparticles (SNPs) by combining advantages of the reversible assembly properties of SNPs using host–guest interactions and of a stimulus-responsive moiety. The SNPs are composed of a core of positively charged poly(ethylene imine) grafted with β-cyclodextrin (CD) and a positively charged ferrocene (Fc)-terminated poly(amidoamine) dendrimer, with a monovalent stabilizer at the surface. Fc was chosen for its loss of CD-binding properties when oxidizing it to the ferrocenium cation. The ionic strength was shown to play an important role in controlling the aggregate growth. The attractive supramolecular and repulsive electrostatic interactions constitute a balance of forces in this system at low ionic strengths. At higher ionic strengths, the increased charge screening led to a loss of electrostatic repulsion and therefore to faster aggregate growth. A Job plot showed that a 1:1 stoichiometry of host and guest moieties gave the most efficient aggregate growth. Different stabilizers were used to find the optimal stopper to limit the growth. A weaker guest moiety was shown to be less efficient in stabilizing the SNPs. Also steric repulsion is important for achieving SNP stability. SNPs of controlled particle size and good stability (up to seven days) were prepared by fine-tuning the ratio of multivalent and monovalent interactions. Finally, reversibility of the SNPs was confirmed by oxidizing the Fc guest moieties in the core of the SNPs

Metal–Organic Frameworks (MOFs) as Multivalent Materials: Size Control and Surface Functionalization by Monovalent Capping Ligands

Control over particle size and composition are pivotal to tune the properties of metal organic frameworks (MOFs), for example, for biomedical applications. Particle-size control and functionalization of MIL-88A were achieved by using stoichiometric replacement of a small fraction of the divalent fumarate by monovalent capping ligands. A fluorine-capping ligand was used to quantify the surface coverage of capping ligand at the surface of MIL-88A. Size control at the nanoscale was achieved by using a monovalent carboxylic acid-functionalized poly(ethylene glycol) (PEG-COOH) ligand at different concentrations. Finally, a biotin–carboxylic acid capping ligand was used to functionalize MIL-88A to bind fluorescently labeled streptavidin as an example towards bioapplications

Traducción al español y validación del cuestionario de retroalimentación en educación médica (FEEDME-Cultura) durante rotaciones clínicas

Introducción: El cuestionario Cultura de retroalimentación en educación médica es una escala validad que determina la percepción de la cultura de retroalimentación en países de habla inglesa. El objetivo de este trabajo es validar este cuestionario en su versión espanola ̃ en estudiantes de medicina peruanos durante una rotación clínica. Métodos: Un estudio observacional, analítico de tipo instrumental fue realizado en 139 estu- diantes de medicina. La validez de la escala fue determinada por V-de-Aiken e intervalos de confianza. Se realizaron pruebas de análisis factorial y alfa de Cronbach. Resultados: Todos los valores fueron estadísticamente significativos cuando se evaluaron con el coeficiente V-de-Aiken. Además, la asimetría y curtosis de todos los ítems son adecuados ya que no exceden el rango >± 1.5. La significancia de la prueba de esfericidad de Barlett (1521.8; gl = 120; p = 0.001) y el coeficiente Kaiser Meyer-Olkin (KMO= .953) fueron adecuados y el análisis factorial exploratorio reveló una estructura de dos factores. El coeficiente de Cronbach de la escala total y sus factores, fue superior a 0,80. Conclusiones: El cuestionario Cultura de retroalimentación en educación médica en espanol ̃ es una escala válida para evaluar la percepción sobre la cultura de retroalimentación en estudi- antes de medicina que están realizando rotación clínica

Chronic Joint Pain 3 Years after Chikungunya Virus Infection Largely Characterized by Relapsing-remitting Symptoms

OBJECTIVE: To determine the frequency of chronic joint pain and stiffness 3 years after infection with chikungunya virus (CHIKV) in a Latin American cohort. METHODS: A cross-sectional followup of 120 patients from an initial cohort of 500 patients who reported joint pain 2 years after infection from the Atlántico Department, Colombia. Patients were clinically diagnosed as having CHIKV during the 2014-2015 epidemic, and baseline and followup symptoms at 40 months were evaluated in serologically confirmed cases. RESULTS: Of the initial 500 patients enrolled in the study, 482 had serologically confirmed chikungunya infection. From this group, 123 patients reported joint pain 20 months after infection, and 54% of those patients reported continued joint pain 40 months after infection. Therefore, 1 out of every 8 people who tested serologically positive for CHIKV infection had persistent joint pain 3 years after infection. Participants who followed up in person were predominantly adult (mean ± SD age 51 ± 14 yrs) and female (86%). The most common type of pain reported in these patients at 40 months post-infection was pain with periods of relief and subsequent reoccurrence, and over 75% reported stiffness after immobility, with 39% experiencing morning stiffness. CONCLUSION: To our knowledge, this is the first report to describe persistent joint pain and stiffness 40 months after viral infection. The high frequency of chronic disease highlights the need to develop prevention and treatment methods. Further studies should be conducted to understand the similarities between post-chikungunya joint pain and rheumatoid arthritis