Hybrid 3D Printing of Synthetic and Cell‐Laden Bioinks for Shape Retaining Soft Tissue Grafts

Despite recent advances in clinical procedures, the repair of soft tissue remains a reconstructive challenge. Current technologies such as synthetic implants and dermal flap autografting result in inefficient shape retention and unpredictable aesthetic outcomes. 3D printing, however, can be leveraged to produce superior soft tissue grafts that allow enhanced host integration and volume retention. Here, a novel dual bioink 3D printing strategy is presented that utilizes synthetic and natural materials to create stable, biomimetic soft tissue constructs. A double network ink composed of covalently cross‐linked poly(ethylene) glycol and ionically cross‐linked alginate acts as a physical support network that promotes cell growth and enables long‐term graft shape retention. This is coupled with a cell‐laden, biodegradable gelatin methacrylate bioink in a hybrid printing technique, and the composite scaffolds are evaluated in their mechanical properties, shape retention, and cytotoxicity. Additionally, a new shape analysis technique utilizing CloudCompare software is developed that expands the available toolbox for assessing scaffold aesthetic properties. With this dynamic 3D bioprinting strategy, complex geometries with robust internal structures can be easily modulated by varying the print ratio of nondegradable to sacrificial strands. The versatility of this hybrid printing fabrication platform can inspire the design of future multimaterial regenerative implants.     

Scale-up of functional properties of pressure-sensitive adhesive from laboratory to industrial plant production: from monomers to label

A waterborne acrylic pressure-sensitive adhesive produced in a commercial plant to label market was successfully developed. In order to reach the required functional properties (i.e. holding time, peel, and loop tack strengths), glass transition temperature, functional monomer content, type of surfactant, and reaction temperature were optimized. A proper balance of wetting and thickening agents content was found taking into consideration their significant unfavorable effect on functional properties.     

Kinetics of microwave heating and drying of drilling fluids and drill cuttings

Drill cutting decontamination by microwave drying has been studied over the past few years and has proved to be a promising technology. This study aimed to investigate fundamental aspects of kinetics of heating and drying of drilling fluids and drill cuttings by microwaves. The microwave heating curve of cuttings free of fluid, drilling fluids, and pure organic compounds usually used in the formulation of these fluids was evaluated to understand the behavior of each component in microwave cutting decontamination. Furthermore, commercial software was used to describe the heating kinetics of the drilling fluids used in this study. The drying kinetics of cuttings contaminated with these drilling fluids was also studied at three temperatures of control. Some classic models of conventional drying of solids were used to describe the removal kinetics of the liquid components present in contaminated cuttings (water and organic compounds). Important aspects related to the interaction of these components in the drying operation and solid heating, water evaporation, and the drag of organic compounds were investigated. Both drilling fluids showed a very similar kinetic heating. Pure organic bases did not show a significant heating. For the same drying time, the removal of paraffin is more intense than the olefin. In respect to organic component removal from cuttings contaminated with both fluids, the kinetic drying curves are similar. The Page model was the one that best describes the drying operation of drill cuttings contaminated with both drilling fluids. The microwave drying model (MDM) model is proposed in this work as a simple modification in the Henderson–Pabis model: the addition of a third parameter. The incorporation of this parameter enabled a better fit of the experimental data. Computational simulations show an electric field with symmetrical patterns for the two BR-MUL fluids analyzed.     

Enzymatic maceration of albedo layer from sour orange (Citrus aurantium L.) with protopectinase-se and measurement of antioxidant activity of the obtained products

Protopectinase-SE was used to macerate the albedo layer from sour orange (Citrus aurantium). The effect of agitation on the process was evaluated and then, antioxidant activity of the resulting preparation was determined by mean of the methodologies DPPH, ABTS, and ferric reducing antioxidant power. The following parameters were assayed: the levels of total phenols, reducing sugars, vitamin C, total flavonones, naringin, and galacturonic acid as well as the preparation’s total acidity. It was found that the use of either a reciprocal or orbital system of agitation, the latter feature achieved with flasks having internal deflectors, yielded similar maceration levels (33 g/100 g). Moreover, the antioxidant activity, as well as the concentrations of vitamin C and total flavonones was the highest with the greatest degree of tissue maceration. These results confirm the effectiveness of the method of maceration for obtaining a form of cellular disruption that result in a maximum conservation of the nutritional characteristics of the processed tissue.