Keratin proteins are the major component of hair, feathers, wool and horns and represent an important source of renewable raw materials for many applications. Regenerated keratin has useful properties such as biocompatibility and biodegradability. Moreover, keratin materials can absorb heavy metal ions, formaldehyde and other VOCs. In this work, regenerated keratin was blended with aqueous solutions of poly(ethylene oxide) (PEO) in different proportion in order to improve its processability. Keratin/PEO nanofibres were produced by electrospinning the blend aqueous solutions. The chemical, physical and rheological characteristics of the blend solutions were correlated with morphology, structural, thermal and mechanical properties of the electrospun mats.

Structure and properties of Keratin/PEO blend nanofibres

Clean and safe water is a fundamental human need for multi-faceted development of society and a thriving economy. Brisk rises in populations, expanding industrialization, urbanization and extensive agriculture practices have resulted in the generation of wastewater which have not only made the water dirty or polluted, but also deadly. Millions of people die every year due to diseases communicated through consumption of water contaminated by deleterious pathogens. Although various methods for wastewater treatment have been explored in the last few decades but their use is restrained by many limitations including use of chemicals, formation of disinfection by-products (DBPs), time consumption and expensiveness. Nanotechnology, manipulation of matter at a molecular or an atomic level to craft new structures, devices and systems having superior electronic, optical, magnetic, conductive and mechanical properties, is emerging as a promising technology, which has demonstrated remarkable feats in various fields including wastewater treatment. Nanomaterials encompass a high surface to volume ratio, a high sensitivity and reactivity, a high adsorption capacity, and ease of functionalization which makes them suitable for application in wastewater treatment. In this article we have reviewed the techniques being developed for wastewater treatment using nanotechnology based on adsorption and biosorption, nanofiltration, photocatalysis, disinfection and sensing technology. Furthermore, this review also highlights the fate of the nanomaterials in wastewater treatment as well as risks associated with their use.

https://www.mdpi.com/1420-3049/26/6/1797/pdf

Nanotechnology in Wastewater Management: A New Paradigm Towards Wastewater Treatment.

Underwater adhesives are in high demand in both commercial and industrial sectors. Compared with adhesives used in dry (air) environments, adhesives used for wet or submerged surfaces in aqueous environments have specific challenges in development and performance. In this review, focus is on adhesives demonstrating macroscopic adhesion to wet/underwater substrates. The current strategies are first introduced for different types of underwater adhesives, and then an overview is provided of the development and performance of underwater adhesives based on different mechanisms and strategies. Finally, the possible research directions and prospects of underwater adhesives are discussed.

Bioinspired Underwater Adhesives

In the last ten years, environmental consciousness has increased worldwide, leading to the development of eco-friendly materials to replace synthetic ones. Natural fibers are extracted from renewable resources at low cost. Their combination with synthetic polymers as reinforcement materials has been an important step forward in that direction. The sustainability and excellent physical and biological (e.g., biocompatibility, antimicrobial activity) properties of these biocomposites have extended their application to the biomedical field. This paper offers a detailed overview of the extraction and separation processes applied to natural fibers and their posterior chemical and physical modifications for biocomposite fabrication. Because of the requirements for biomedical device production, specialized biomolecules are currently being incorporated onto these biocomposites. From antibiotics to peptides and plant extracts, to name a few, this review explores their impact on the final biocomposite product, in light of their individual or combined effect, and analyzes the most recurrent strategies for biomolecule immobilization.

https://www.mdpi.com/2218-273X/10/1/148/pdf

Biofunctionalization of Natural Fiber-Reinforced Biocomposites for Biomedical Applications.

Biopolymers are playing a vital role in biomedical applications. Among them, protein based biopolymers are utilized for the fabrication of tissue engineering constructs, therapeutic molecule delivery carriers, emulsifiers and food packaging materials. Wide ranges of proteins are extracted from animal or plant sources and are being utilized for the fabrication of scaffolds for regenerative tissue engineering application. Here, an overview about the protein structure, extraction procedure, solubility and various formulation based proteins used in the literature are discussed. Biopolymers display several advantageous such as biocompatibility and degradability by enzymes. Methods to overcome the disadvantages of these proteins such as immunogenicity, antigenicity and solubility will be reported. Various crosslinking reagents specific to protein chemistry will be as well discussed. TOC Protein based biopolymers are one of the promising class of biomaterials due to their biocompatibility and biodegradability. In this review, protein based biopolymers derived from animals and plants are elaborately discussed. Chemical structures of biopolymer and crosslinking based stabilization of biopolymer are also provided. Different formulations fabricated using

/pdf/overview-of-protein-based-biopolymers-for-biomedical-2ecups4wkl.pdf

Overview of Protein-Based Biopolymers for Biomedical Application

We prepared the small pseudopeptide Lau-l-Dopa(OBn)2-d-Oxd-OBn (Lau = lauric acid; l-Dopa = l-3,4-dihydroxyphenylalanine; d-Oxd = (4R,5S)-4-methyl-5-carboxyl-oxazolidin-2-one; Bn = benzyl) through a number of coupling reactions between lauric acid, protected l-Dopa and d-Oxd with an excellent overall yield. The ability of the product to form supramolecular organogels has been tested with different organic solvents of increasing polarity and compared with the results obtained with the small pseudopeptide Fmoc-l-Dopa(OBn)2-d-Oxd-OBn. The mechanical and rheological properties of the organogels demonstrated solvent-dependent properties, with a storage modulus of 82 kPa for the ethanol organogel. Finally, to have a preliminary test of the organogels’ ability to adsorb pollutants, we treated a sample of the ethanol organogel with an aqueous solution of Rhodamine B (RhB) for 24 h. The water solution slowly lost its pink color, which became trapped in the organogel.

Low Molecular Weight Gelators Based on Functionalized l-Dopa Promote Organogels Formation.

Supramolecular hydrogels, obtained from small organic molecules, may be advantageous over polymeric ones for several applications, because these materials have some peculiar properties that differentiate them from the traditional polymeric hydrogels, such as elasticity, thixotropy, self-healing propensity, and biocompatibility. We report here the preparation of strong supramolecular pseudopeptide-based hydrogels that owe their strength to the introduction of graphene in the gelling mixture. These materials proved to be strong, stable, thermoreversible and elastic. The concentration of the gelator, the degree of graphene doping, and the nature of the trigger are crucial to get hydrogels with the desired properties, where a high storage modulus coexists with a good thixotropic behavior. Finally, NIH-3T3 cells were used to evaluate the cell response to the presence of the most promising hydrogels. The hydrogels biocompatibility remains good, if a small degree of graphene doping is introduced.

Tuning Mechanical Properties of Pseudopeptide Supramolecular Hydrogels by Graphene Doping.

Most supramolecular gels are stable or assumed to be stable over time, and aging effects are often not studied. However, some gels do show clear changes on aging, and a small number of systems exhibit gel-to-crystal transitions. In these cases, crystals form over time, typically at the expense of the network underpinning the gel; this leads to the gel falling apart. These systems are rare, and little is known about how these gel-to-crystal transitions occur. Here, we use a range of techniques to understand in detail a gel-to-crystal transition for a specific functionalised dipeptide based gelator. We show that the gel-to-crystal transition depends on the final pH of the medium which we control by varying the amount of glucon-δ-lactone (GdL) added. In the gel phase, at low concentrations of GdL, and at early time points with high concentrations of GdL, we are able to show the nanometre scale dimensions of the self-assembled fibre using SAXS; however there is no evidence of molecular ordering of the gel fibres in the WAXS. At low concentrations of GdL, these self-assembled fibres stiffen with time but do not crystallise over the timescale of the SAXS experiment. At high concentrations of GdL, the fibres are already stiffened, and then, as the pH drops further, give way to the presence of crystals which appear to grow preferentially along the direction of the fibre axis. We definitively show therefore that the gel and crystal phase are not the same. Our work shows that many assumptions in the literature are incorrect. Finally, we also show that the sample holder geometry is an important parameter for these experiments, with the rate of crystallisation depending on the holder in which the experiment is carried out.

/pdf/understanding-gel-to-crystal-transitions-in-supramolecular-3jtxiny840.pdf

Understanding gel-to-crystal transitions in supramolecular gels.

Seashells are a calcium-carbonate-based material that can be converted into valuable advanced functional materials. Seashells are also a waste material from aquaculture. They are produced in millio...

New Material Perspective for Waste Seashells by Covalent Functionalization

Multicomponent supramolecular gels provide opportunities to form materials that are not accessible when using the single components alone. Different scenarios are possible when mixing multiple components, from complete co-assembly (mixing of the components within the self-assembled structures formed) to complete self-sorting such that each structure contains only one of the components. Most examples of multicomponent gels that currently exist form stable gels. Here, we show that this can be used to control the mechanical properties of the gels, but what is probably most exciting is that we show that we can use a magnetic field to control the shape of the crystals. The gelling component aligns in a magnetic field and so results in anisotropic crystals being formed.

/pdf/exploiting-and-controlling-gel-to-crystal-transitions-in-20w7w717tm.pdf

Demetra Giuri

Papers

Low Molecular Weight Gelators Based on Functionalized l-Dopa Promote Organogels Formation.

Tuning Mechanical Properties of Pseudopeptide Supramolecular Hydrogels by Graphene Doping.

Understanding gel-to-crystal transitions in supramolecular gels.

New Material Perspective for Waste Seashells by Covalent Functionalization

Exploiting and controlling gel-to-crystal transitions in multicomponent supramolecular gels