Self-assembly of keratin peptides: Its implication on the performance of electrospun PVA nanofibers

Lacticaseibacillus rhamnosus encapsulated cross-linked Keratin-Chitosan hydrogel for removal of patulin from apple juice

In this study, we developed a hydrogel from cross-linked keratin and chitosan (KC) to remove patulin (PAT) from apple juice. We explored the potential of incorporating Lactobacillus rhamnoses into the KC hydrogel (KC-LR) and tested its effectiveness in removing PAT from simulated juice solutions and real apple juice. The KC hydrogel was developed through a dynamic disulfide cross-linking reaction. This cross-linked hydrogel network provided excellent stability for the probiotic cells, achieving 99.9 % immobilization efficiency. In simulated juice with 25 mg/L PAT, the KC and KC-LR hydrogels showed removal efficiencies of 85.2 % and 97.68 %, respectively, using 15 mg mL-1 of the prepared hydrogel at a temperature of 25 °C for 6 h. The KC and KC-LR hydrogels achieved 76.3 % and 83.6 % removal efficiencies in real apple juice systems, respectively. Notably, the encapsulated probiotics did not negatively impact the juice quality and demonstrated reusability for up to five cycles of the PAT removal process.

Recent advances in electrospun protein fibers/nanofibers for the food and biomedical applications

Electrospinning (ES) is one of the most investigated processes for the convenient, adaptive, and scalable manufacturing of nano/micro/macro-fibers. With this technique, virgin and composite fibers may be made in different designs using a wide range of polymers (both natural and synthetic). Electrospun protein fibers (EPF) shave desirable capabilities such as biocompatibility, low toxicity, degradability, and solvolysis. However, issues with the proteins' processibility have limited their widespread utilization. This paper gives an overview of the features of protein-based biomaterials, which are already being employed and has the potential to be exploited for ES. State-of-the-art examples showcasing the usefulness of EPFs in the food and biomedical industries, including tissue engineering, wound dressings, and drug delivery, provided in the applications. The EPFs' future perspective and the challenge they pose are presented at the end. It is believed that protein and biopolymeric nanofibers will soon be manufactured on an industrial scale owing to the limitations of employing synthetic materials, as well as enormous potential of nanofibers in other fields, such as active food packaging, regenerative medicine, drug delivery, cosmetic, and filtration.

Lanthanum oxide nanoparticle-collagen bio matrix induced endothelial cell activation for sustained angiogenic response for biomaterial integration

Rare earth lanthanum oxide nanoparticle reinforced collagen biomatrix that elicited the endothelial cell activation to promote angiogenesis for biomaterial integration was developed and evaluated in the present study. The structural integrity of collagen was not compromised on crosslinking of lanthanum oxide nanoparticle to collagen biomolecule. As-synthesised collagen biomatrix was shown to have improved mechanical strength, a lesser susceptibility to proteolytic degradation and good swelling properties. Superior cytocompatibility, hemocompatibility and minimal ROS generation was observed with Lanthanum oxide nanoparticle reinforced collagen bio matrix. The Lanthanum oxide nanoparticle reinforced collagen bio matrix elicited endothelial cell activation eliciting pro-angiogensis as observed in tube formation and aortic arch assays. The bio-matrix promoted the infiltration and proliferation of endothelial cells which is an unexplored domain in the area of tissue engineering that is very essential for biomaterial integration into host tissue. The wound healing effect of Lanthanum oxide nanoparticle stabilized collagen showed enhanced cell migration in vitro in cells maintained in Lanthanum oxide nanoparticle reinforced collagen bio matrix. The study paves the way for developing rare earth-based dressing materials which promoted biomatrix integration by enhancing vascularisation for tissue regenerative applications in comparison with traditional biomaterials.

Insights into protein-ionic liquid interaction: A comprehensive overview on theoretical and experimental approaches

Owing to highly tunable nature, ionic liquids are nesting stance in the scientific community for a wide variety of applications ranging from electrochemistry to product purification, from chemical and biomedical applications to biotechnological interventions and proteomics. Proteins are unstable in its native form and several attempts have been made to stabilize them by addition of various additives. This review focusses on the studies conducted to improve protein stability with ionic liquids along with an emphasis on the mechanism of interaction. This review also specifies and discusses about the brief introduction to ionic liquids, evolution of first-, second-, and third generation of liquids over the years and their selection criterion and applications. Though, there are several elegant reviews available on proteins-ionic liquids interaction, this review systematically highlights the effect of ionic liquids viz., imidazolium, ammonium, phosphonium and choline-based ionic liquids (amino acid-based anions & classical anions) on fibrous proteins viz., collagen and keratin and globular proteins viz., bovine serum albumin and cytochrome c. Thus, this review elaborates the thorough investigations conducted to explore the stabilizing properties of ionic liquids over fibrous and globular proteins.

Effective utilization of tannery hair waste to develop a high-performing re-tanning agent for cleaner leather manufacturing

Accumulation of hair waste is a major burden to the leather industry, causing a negative impact on the industry's sustainable development. The industry is already bogged down by the usage of synthetic re-tanning agents that are not only extremely challenging for biodegradation but also release free-form of formaldehyde in the final leather stage. This research work focuses on developing a formaldehyde-free bio-based re-tanning agent from hair waste. In order to do so, hair waste is subjected to alkali hydrolysis and subsequently graft-copolymerized with methacrylic acid (MAA). These treatments were optimal using 20 % (w/w) sodium hydroxide and thermal activity at 90 °C. This resulted in effective hydrolysis of red sheep hair, which was the ideal candidate in this study. The hydrolysate was subjected to monomer in situ polymerization (using MAA) with potassium per sulfate/sodium meta-bisulphite redox system, leading to the development of keratin hydrolysate-g-methacrylic acid (KH-g-MA) copolymer (this was noted both at a laboratory level and pilot scale). The obtained KH-g-MA copolymer exhibited ideal characteristics such as increased protein content (78.3 ± 1.2), appropriate particle size (1516 nm), suitable pH (5) and required viscosity of 512 cP. The developed KH-g-MA copolymer was then applied as a re-tanning agent in the leather manufacturing process. Significant improvement in leather's mechanical strength characteristics was observed. In addition, the organoleptic properties of leather such as fullness, softness and grain tightness showed much improvement. Scanning electron microscopy (SEM) showed an enhanced surface smoothness and filling of the voids in experimental leather in comparison to the control leather. This recycle and reuse strategy of hair waste not only helps resolve issues with handling of hair solid waste but also results in producing an eco-friendly re-tanning agent in leather manufacturing, thereby paving the way for cyclic economic utilization and cleaner environment.

Flexible MnO nanoparticle-anchored N-doped porous carbon nanofiber interlayers for superior performance lithium metal anodes

The mounting requirements for electric apparatus and vehicles stimulate the rapid progress of energy storage systems. Lithium (Li) metal is regarded as one of the most prospective anodes for high-performance cells. However, the uneven dendrite growth is one of the primary conundrums that hampers the use of the Li metal anode in rechargeable Li batteries. Achieving even Li deposition is crucial to solve this concern. In this study, a stable interlayer based on electrospun flexible MnO nanoparticle/nitrogen (N)-doped (polyimide) PI-based porous carbon nanofiber (MnO-PCNF) films was effectively prepared via electrospinning and in situ growth of MnO to reduce the growth of Li dendrites. It is revealed that the attraction of implanted MnO towards Li, the lithiophilic nature of N dopants and the capillary force of porous architectures are beneficial to the preeminent Li wettability of the MnO-PCNF interlayer. Furthermore, the wettable, stable and conductive structure of the MnO-PCNF interlayer can be retained well, offering rapid charge transfer to Li redox reactions, reduced local current density during the cycling process and homogeneous distribution of deposited Li. Consequently, anodes with MnO-PCNF interlayers can relieve the volume change and inhibit the growth of Li dendrites, demonstrating a remarkable lifetime for lithium metal cells at high current.

Improved filtration for dye removal using keratin-polyamide blend nanofibrous membranes

Dyes from industrial wastewaters represent one of the most hazardous pollutants as they are not effectively biodegradable. The present work is focused to study the novel properties of keratin-polyamide blend nanofibrous filtration membranes for treating wastewaters containing dye. Keratin protein was extracted from goat hair, a tannery waste through sulphitolysis process. The extracted keratin was blended with polyamide to prepare a nanofibrous membrane through the electrospinning process. The fabricated pristine polyamide and keratin-altered polyamide membranes were characterized and compared for their properties. Effects of solution pH, dye concentration, membrane flux, and membrane capacity have been examined. Very fine nanofibers and enhanced porosity drive the membrane to enhanced flux and higher filtration efficiencies. At pH 2, the dye removal efficiency of the blend membranes was 100, 99, 98, 90, and 83% for 100, 200, 250, 300, and 400 ppm concentrations of dye, respectively. The keratin-polyamide blend membrane exhibited better properties in all aspects. The results of this present investigation indicate that the presence of keratin in filtration membranes is promising for dye removal from the effluents.

Keratin Associations with Synthetic, Biosynthetic and Natural Polymers: An Extensive Review

Among the biopolymers from animal sources, keratin is one the most abundant, with a major contribution from side stream products from cattle, ovine and poultry industry, offering many opportunities to produce cost-effective and sustainable advanced materials. Although many reviews have discussed the application of keratin in polymer-based biomaterials, little attention has been paid to its potential in association with other polymer matrices. Thus, herein, we present an extensive literature review summarizing keratin's compatibility with other synthetic, biosynthetic and natural polymers, and its effect on the materials' final properties in a myriad of applications. First, we revise the historical context of keratin use, describe its structure, chemical toolset and methods of extraction, overview and differentiate keratins obtained from different sources, highlight the main areas where keratin associations have been applied, and describe the possibilities offered by its chemical toolset. Finally, we contextualize keratin's potential for addressing current issues in materials sciences, focusing on the effect of keratin when associated to other polymers' matrices from biomedical to engineering applications, and beyond.