No abstract

Los materiales poliméricos han tenido una imagen desfavorable, ya que son asociados con contaminación. Sin embargo, estos son de gran importancia para la biomedicina. Los polímeros son materiales muy versátiles, se pueden obtener de múltiples configuraciones químicas y mezclas para generar materiales compuestos con propiedades sinérgicas. En esta investigación se realizó un análisis científico y tecnológico de las aplicaciones biomédicas de biomateriales poliméricos y se recopila algunas de sus aplicaciones, propiedades mecánicas y características importantes para la industria biomédica. Los biomateriales poliméricos son una temática de punta como se refleja en el número de artículos científicios y de patentes. En la actualidad, estos biomateriales pueden llegar a reemplazar, reforzar o cumplir una función específica en el cuerpo humano. No obstante, debido a la complejidad de los sistemas biológicos aún se siguen presentando reacciones inmunes, que evitan el desarrollo de tejidos u órganos funcionales a escala de laboratorio.

No abstract

Bacterial nanocellulose (BNC) is a nano fibrillar polymer, which is biostable and non-resorbable when inside the human body. It has excellent biocompatibility and a microstructure with high mechanical strength, and if processed correctly, can mimic the extra-cellular matrix architecture. BNC, modified with bone-like minerals such as calcium phosphates, can improve cell adhesion and promote the formation of new bone tissues. As a result of the need for three-dimensional (3D) porous scaffolds for bone tissue regeneration, this study evaluated the effect of calcium phosphate mineralization process on BNC and (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized BNC scaffolds, to understand the influence of hydroxyl or carboxylate groups on the nucleation and growth of apatite crystals. The results showed 3D scaffolds with controlled microporosity, between 50 and 350 lm, and interconnected pores. The porous morphology of the TEMPO-oxidized BNC scaffolds varied significantly with the oxidation time and only remained preserved after 60 min of the TEMPO-mediated oxidation. BNC and TEMPO-oxidized BNC scaffolds were used to compare two different mineralization treatments. The growth of homogeneously distributed microcrystals was observed in the unmodified BNC scaffolds, whereas heterogeneously distributed microcrystals were observed in the TEMPO-oxidized BNC scaffolds because of the oxidation treatment which affected the continuity of the surface by fracturing some fibers. Also, in vitro cell studies revealed good cellular adhesion and high cell viability in the modified and unmodified BNC scaffolds. Most of the modifications seemed adequate for cellular adhesion.

A comparative study was conducted on the efficiency of mercury removal using bacterial nanocellulose (BNC) membranes obtained from the fermentation of the microorganism Komagataeibacter medellinensis, in contrast with its oxidized analog obtained by modifying the bacterial nanocellulose membranes via oxidation with 2,2,6,6-Tetramethylpiperidine-1-oxyl. Both types of membranes (modified and unmodified) were characterized to identify variations in the Physico-chemical parameters after modification. FTIR spectra confirmed the chemical modification of cellulose in all reaction conditions by the presence of a new characteristic band at ∼1730 cm−1, corresponding to the new carboxylic groups produced by the oxidative process, and the decline of the band at ∼1,650 cm−1, corresponding to the hydroxyl groups of the C6 carbon. While the XRD profiles indicated that the percentage of BNC crystallinity decreased and the SEM images showed that the nanoribbon network was interrupted as the amount of oxidizing agent increased. The kinetics of mercury removal from both types of membrane was evaluated by calculating the concentration of mercury at different times and establishing a mathematical model to describe the kinetics of this process. The modified membranes improved significantly the adsorption process of the metal ion and it was found that the modification that results in the greatest adsorption efficiency was BNC-m 7.5 with a value of 92.97%. The results obtained suggest that the modification of the bacterial nanocellulose membranes by oxidation transcendentally improves the mercury removal capacity, outlining the modified membranes as an excellent material for mercury removal in wastewater.