Critical Study on the Tube-to-Chip Luer Slip Connectors.

Luer slip is one of the gold standards for chip-to-world interface in microfluidics. They have outstanding mechanical and operational robustness in a broad range of applications using water and solvent-based liquids. Still, their main drawbacks are related to their size: they have relatively large dead volumes and require a significant footprint to assure a leak-free performance. Such aspects make their integration in systems with high microchannel density challenging. To date, there has been no geometrical optimization of the Luer slips to provide a solution to the mentioned drawbacks. This work aims to provide the rules toward downscaling the Luer slips. To this effect, seven variations of the Luer slip male connectors and five variations of Luer slip female connectors have been designed and manufactured focusing on the reduction of the size of connectors and minimization of the dead volumes. In all cases, female connectors have been developed to pair with the corresponding male connector. Characterization has been performed with a tailor-made test bench in which the closure force between male and female connectors has been varied between 7.9 and 55 N. For each applied closure force, the test bench allows liquid pressures to be tested between 0.5 and 2.0 bar. Finally, the analysis of a useful life determines the number of cycles that the connectors can withstand before leakage.

ß-Glycerol phosphate/genipin chitosan hydrogels: A comparative study of their properties and diclofenac delivery.

Thermosensitive hydrogels based on polysaccharides are suitable candidates for the design of biodegradable and biocompatible injectable drug delivery systems. Thus, the combination of chitosan (CHI) and ß-glycerol phosphate disodium salt (ß-GP) has been intensively investigated to develop thermo-induced physical gels. With the aim of exploring the possibilities of optimization of these hydrogels, in this work, chitosan, ß-GP and naturally extracted crosslinking agent, genipin (GEN), have been successfully combined, obtaining co-crosslinked hydrogels with both in situ physical and covalent crosslinking. A wide range of ß-GP concentrations have been selected in order to analyze its influence on a variety of properties, including gelation time, pore size, water uptake ability, in vitro hydrolytic and enzymatic degradation, mucoadhesion and mechanical and rheological properties. Furthermore, the potential application of the developed systems for the administration and controlled release of an anti-inflammatory anionic drug, such as diclofenac, has been successfully demonstrated.

Photocatalytic and antimicrobial multifunctional nanocomposite membranes for emerging pollutants water treatment applications.

Emerging pollutants represent a new global problem for water quality. As these compounds get into the environment, they cause severe threats to aquatic environments and human health and are typically resistant to conventional wastewater treatments. In this work, TiO2 nanoparticles surface was functionalized with silver (Ag) nanoparticles, and solvent cast and electrospun membranes of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared with different concentrations of TiO2 and Ag-TiO2 to produce a multifunctional material. The photocatalytic activity of the nanocomposites was evaluated through the degradation of norfloxacin under ultraviolet (UV) and visible radiation. It is shown that nanocomposites with Ag-TiO2 show the highest degradation efficiencies: 64.2% under UV and 80.7% under visible radiation, for 90 and 300 min, respectively. Furthermore, the recyclability of the membranes has also been demonstrated. Finally, it is shown the antimicrobial activity of the nanocomposite membranes, demonstrating the suitability of the Ag-TiO2/PVDF-HFP nanocomposites as multifunctional photocatalytic and antimicrobial membranes for water remediation applications.

Silk Fibroin Bending Actuators as an Approach Toward Natural Polymer Based Active Materials.

This work reports on the development of ionic liquid (IL)/silk fibroin (SF) composite films as electroactive polymers actuators. Different contents (20, 40, and 60% wt) of 1-butyl-3-methylimidazolium tricyanomethanide ([Bmim][C(CN3)]) and choline dihydrogen phosphate ([Ch][DHP]) ILs were incorporated into the SF polymer matrix. Due to IL-SF interactions, morphological changes such as globule-like nanostructures are induced in the samples. High concentrations of IL promote SF ß-sheet formation above 65%. Further, an increase in the thermal stability of the SF was observed through the incorporation of [Bmim][C(CN3)]. IL type and content allow tuning of the electrical response as well as achieving bending actuation. [Bmim][C(CN3)]/SF samples allow bending responses up to 0.5 at an applied voltage of 3 V. In conclusion, this work demonstrates the ability of IL/SF composites to act as electroactive polymer actuators and opens new perspectives in the application of natural resources for smart materials.