Starch Reinforcement of Raw Earth Constructions

The restoration, the protection, or the creation of earthen buildings require improving the mechanical strength of the material. The first way to do that is to use inorganic additives, but these additives change the structural properties of earth and have a high carbon footprint. In contrast, the other way to consolidate is the use of organic additives such as vegetal derivatives that rearrange the minerals in the earth, with the lowest carbon footprint as they are from waste management. After preliminary tests with ten different organic additives from traditional recipes, we found that wheat starch improves the earth strength up to 50 %. In this study, we related the mechanical strengthening to the physicochemical interactions between clays and starch. We focus on three clays that represent the three main groups of clays: kaolinite, illite and montmorillonite. For this study, we mainly focused on compressive test and rheological tests. We showed that the improvement of the mechanical strength with starch is depending on clay nature and their chemistry. Then, we can recommend formulations based on the earth nature for new sustainable buildings. Furthermore, we can understand why it was an interesting way to use starch as a strengthening agent in traditional recipes and how it could be used to repair and protect buildings made of earthen material.

Hydrogels Classification According to the Physical or Chemical Interactions and as Stimuli-Sensitive Materials

Hydrogels are attractive biomaterials with favorable characteristics due to their water uptake capacity. However, hydrogel properties are determined by the cross-linking degree and nature, the tacticity, and the crystallinity of the polymer. These biomaterials can be sorted out according to the internal structure and by their response to external factors. In this case, the internal interaction can be reversible when the internal chains are led by physicochemical interactions. These physical hydrogels can be synthesized through several techniques such as crystallization, amphiphilic copolymers, charge interactions, hydrogen bonds, stereo-complexing, and protein interactions. In contrast, the internal interaction can be irreversible through covalent cross-linking. Synthesized hydrogels by chemical interactions present a high cross-linking density and are employed using graft copolymerization, reactive functional groups, and enzymatic methods. Moreover, specific smart hydrogels have also been denoted by their external response, pH, temperature, electric, light, and enzyme. This review deeply details the type of hydrogel, either the internal structure or the external response. Furthermore, we detail some of the main applications of these hydrogels in the biomedicine field, such as drug delivery systems, scaffolds for tissue engineering, actuators, biosensors, and many other applications.

Addition of phenolic compounds to bread: antioxidant benefits and impact on food structure and sensory characteristics

The use of flours or phenolic extracts obtained from non-traditional sources or agri-food industry by-products has been a strategy used to formulate new bakery products with characteristics of a functional food. However, phenolic compounds present great structural diversity, as well as the ability to interact in a complex way with the macromolecules that constitute the bread matrix. Therefore, the addition of these flours, extracts or pure compounds produces various effects on the microstructure of bread, and several of its sensory properties. This is mainly due to interactions between phenolic compounds and gluten proteins. The objective of this review is to analyze some of the most recent published works on the addition of phenolic compounds in wheat bread to identify the type of positive and negative effects that have been observed and how they can be related to the physicochemical interactions between phenolic compounds and the macromolecules that constitute the food matrix, mainly gluten. The effect of monomeric and polymeric phenolic compounds on the strength of these interactions and on the properties of dough and bread are discussed. Graphical Abstract

Silane Modification of Mesoporous Materials for the Optimization of Antiviral Drug Adsorption and Release Capabilities in Vaginal Media

Three different functionalities have been incorporated into mesoporous materials by means of a coupling reaction with the siloxanes 3-glycidoxypropyl-trimethoxysilane (GLYMO), 3-methacryloxypropyl-trimethoxysilane (MEMO), and 3-mercaptopropyl-trimethoxysilane (MPTMS). The disposition of the different functional groups, as well as the interaction mechanism, with the mesoporous substrate has been identified. The amount of the antiviral drug acyclovir (ACV) adsorbed depends not only on the available surface area but also on the chemical or physicochemical interactions between functionalities. The drug adsorption isotherm of the materials functionalized with GLYMO and MPTMS follow mechanisms dependent on the different surface coverage and the possibilities to establish physicochemical interactions between the drug molecule and the functionalities. On the contrary, when functionalizing with MEMO, the dominant adsorption mechanism is characteristic of chemically bonded adsorbates. The ACV release kinetics is best fitted to the Weibull model in all the functionalized materials. When the MTPMS is used as a functionalizing agent, the drug diffusion occurs at low kinetics and homogeneously along the mesoporous channels.

Physicochemical Interactions in Nanofunctionalized Alginate/GelMA IPN Hydrogels

Polymeric hydrogels are currently at the center of research due to their particular characteristics. They have tunable physical, chemical, and biological properties making them a material of choice for a large range of applications. Polymer-composite and nanocomposite hydrogels were developed to enhance the native hydrogel’s properties and to include numerous functionalities. In this work, alginate/gelatin-methacryloyl-based interpenetrating polymer network hydrogels were prepared with different alginate concentrations and investigated before and after the functionalization with nanoliposomes. The multiscale analysis was obtained through Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. The results show interactions between two polymers as well as between the nanoliposomes and biopolymer.

Why Are Wet Wipes So Difficult to Preserve? Understanding the Intrinsic Causes

Over the last two decades, significant advances have been made in developing disposable baby wet wipes. Wet wipes consist of two main components: nonwoven fabric and liquid. Being more than 90% water, wet wipes are more susceptible to microbial growth than typical personal care products; hence, high concentrations of preservative compounds are often used to ensure extended protection against contamination. However, there is an obvious tendency to minimize the concentration of irritating actives. Baby wet wipes should contain particularly mild surfactants, well-tolerated preservatives, and a buffer system maintaining the formulation pH at a suitable level for the infant’s skin. Efforts have been centered on removing ingredients with irritation potential, such as phenoxyethanol. In addition, a move towards more natural fabrics is occurring. However, these modifications provoke new challenges in preserving the final products. The nature and composition of the fiber can influence the interactions between the preservative and the wipe, subsequently affecting the performance of the preservative system. In this study, we analyzed the causes of the challenge in preserving wet wipes. We found that fabrics containing natural fibers are the main source of contamination, promoting the generation of biofilms on their surfaces. Moreover, the hydrophilic–lipophilic balance (HLB) was utilized to rationalize the physicochemical interactions between the fabric and the preservatives.