A Chitosan-based Hydrogel with PLCL, ZnO NPs, and Oligoelements: A Promising Antibiotic Scaffold for Tissue Engineering / Hidrogel de Quitosano con PLCL, ZnO NPs y Oligoelementos: Un Andamio Antibacteriano Prometedor para Ingeniería de Tejidos

ABSTRACT Tissue engineering involves anchorage-dependent cells cultured on scaffolds, with growth factors added to facilitate cell proliferation. Its use in transplants implies the risk of bacterial infection. The current contribution describes the preparation and antibacterial evaluation of a chitosan-based hydrogel physically cross-linked with poly(l-lactic-coɛ-caprolactone) (PLCL) and enriched with zinc oxide nanoparticles (ZnO NPs) and trace elements (potassium and magnesium). The material was developed as a scaffold with built-in antibacterial properties. Chitosan and PLCL are biocompatible support materials applied in medicine for the repair and regeneration of damaged tissues, objectives promoted by ZnO NPs and the aforementioned trace elements. The ZnO NPs were elaborated by chemical coprecipitation. The materials were characterized by XRD, FT-IR, and SEM. Antibacterial testing was performed with strains of Escherichia coli and Staphylococcus aureus by the Kirby-Bauer method, in accordance with the NCCLS and CLSI guidelines. It was possible to obtain a homogeneous hydrogel with adequate morphology and distribution of elements. The hydrogel with 300 mM of Mg, K, and ZnO NP's showed antibacterial inhibition halos of 13 mm for S. aureus and 19 mm for E. coli. This innovative biomaterial with trace elements holds promise for tissue engineering by considering the challenge of bacterial infection.

RESUMEN La ingeniería de tejidos involucra el uso de células cultivadas en andamios con adiciones de factores de crecimiento para facilitar la proliferación celular. Su uso en trasplantes implica riesgo de infección bacteriana. La contribución actual describe la preparación y evaluación antibacteriana de un hidrogel a base de quitosano físicamente reticulado con poli (l-láctico-co-ɛ-caprolactona) (PLCL) enriquecido con nanopartículas de óxido de zinc (NP de ZnO) y oligoelementos (potasio y magnesio). El material se desarrolló como un andamio con propiedades antibacterianas. El quitosano y el PLCL son materiales de soporte biocompatibles aplicados en medicina para la reparación y regeneración de tejidos dañados, propiedades promovidas por las NP´s de ZnO y los oligoelementos antes mencionados. Las NP de ZnO se elaboraron mediante coprecipitación química. Los materiales se caracterizaron por DRX, FT-IR y SEM. Las pruebas antibacterianas se realizaron con cepas de Escherichia coli y Staphylococcus aureus por el método de KirbyBauer de acuerdo con las guías NCCLS y CLSI. Se pudo obtener un hidrogel homogéneo con adecuada morfología y distribución de elementos. El hidrogel con 300 mM de NP ZnO y oligoelementos mostró halos de inhibición antibacteriana de 13 mm para S. aureus y 19 mm para E. coli. Este biomaterial innovador con oligoelementos es prometedor para la ingeniería de tejidos al considerar el desafío de la infección bacteriana.

The D543N polymorphism of the SLC11A1/NRAMP1 gene is associated with treatment failure in male patients with pulmonary tuberculosis.

BACKGROUND: Polymorphisms in SLC11A1/NRAMP1 have shown an important association with susceptibility to tuberculosis and progression to active disease. However, whether there is an association of these polymorphisms with treatment failure is unknown. The aim of this study was to determine the association of SLC11A1 polymorphisms with treatment failure in Mexican subjects with pulmonary tuberculosis. METHODS: Thirty-three subjects with treatment failure were paired by age and body mass index with 33 patients who successfully completed treatment and were considered cured. We assessed the polymorphisms of SLC11A1 in the regions of D543N and INT4 via polymerase chain reaction real-time TaqMan® single nucleotide polymorphism (SNP) genotyping. RESULTS: We found that D543N (G/A genotype) was associated with treatment failure in patients with pulmonary tuberculosis [odds ratio (OR) 11.61, 95% confidence interval (CI) 3.66-36.78]. When adjusted by gender, this association remained significant in males (OR 11.09, 95% CI 3.46-35.51). CONCLUSIONS: In our male population, the presence of the D543N polymorphism of SLC11A1 is a risk factor for treatment failure. This finding should be confirmed in other populations.