Structure and antibacterial activity relationships of native and amyloid fibril lysozyme loaded on layered double hydroxide

Well-designed protein amyloid nanofibrils composites as versatile and sustainable materials for aquatic environment remediation: A review

Amyloid nanofibrils (ANFs) are supramolecular polymers originally classified as pathological markers in various human degenerative diseases. However, in recent years, ANFs have garnered greater interest and are regarded as nature-based sustainable biomaterials in environmental science, material engineering, and nanotechnology. On a laboratory scale, ANFs can be produced from food proteins via protein unfolding, misfolding, and hydrolysis. Furthermore, ANFs have specific structural characteristics such as a high aspect ratio, good rigidity, chemical stability, and a controllable sequence. These properties make them a promising functional material in water decontamination research. As a result, the fabrication and application of ANFs and their composites in water purification have recently gained considerable attention. Despite the large amount of literature in this field, there is a lack of systematic review to assess the gap in using ANFs and their composites to remove contaminants from water. This review discusses significant advancements in design techniques as well as the physicochemical properties of ANFs-based composites. We also emphasize the current progress in using ANFs-based composites to remove inorganic, organic, and biological contaminants. The interaction mechanisms between ANFs-based composites and contaminants are also highlighted. Finally, we illustrate the challenges and opportunities associated with the future preparation and application of ANFs-based composites. We anticipate that this review will shed new light on the future design and use of ANFs-based composites.

Triggering of Polymer-Degrading Enzymes from Layered Double Hydroxides for Recycling Strategies

The use of degrading enzymes in polymer formulation is a very attractive strategy to manage the end-of-life of plastics. However, high temperatures cause the denaturation of enzymes and the loss of their catalytic activity; therefore, protection strategies are necessary. Once protected, the enzyme needs to be released in appropriate media to exert its catalytic activity. A successful protection strategy involves the use of layered double hydroxides: cutinase, selected as a highly degrading polyester hydrolytic enzyme, is thermally protected by immobilization in Mg/Al layered double hydroxide structures. Different triggering media are here evaluated in order to find the best releasing conditions of cutinase from LDH. In detail, phosphate and citrate-phosphate buffers, potassium carbonate, sodium chloride, and sodium sulfate solutions are studied. After the comparison of all media in terms of protein release and activity retained, phosphate buffer is selected as the best candidate for the release of cutinase from LDH, and the effect of pH and concentration is also evaluated. The amount of the enzyme released is determined with the Lowry method. Activity tests are performed via spectrophotometry.

Amyloid peptides with antimicrobial and/or microbial agglutination activity

Abstract

Microbe (including bacteria, fungi, and virus) infection in brains is associated with amyloid fibril deposit and neurodegeneration. Increasing findings suggest that amyloid proteins, like Abeta (Aβ), are important innate immune effectors in preventing infections. In some previous studies, amyloid peptides have been linked to antimicrobial peptides due to their common mechanisms in membrane-disruption ability, while the other mechanisms of bactericidal protein aggregation and protein function knockdown are less discussed. Besides, another important function of amyloid peptides in pathogen agglutination is rarely illustrated. In this review, we summarized and divided the different roles and mechanisms of amyloid peptides against microbes in antimicrobial activity and microbe agglutination activity. Besides, the range of amyloids’ antimicrobial spectrum, the effectiveness of amyloid peptide states (monomers, oligomers, and fibrils), and cytotoxicity are discussed. The good properties of amyloid peptides against microbes might provide implications for the development of novel antimicrobial drug.

Key points

• Antimicrobial and/or microbial agglutination is a characteristic of amyloid peptides.

• Various mechanisms of amyloid peptides against microbes are discovered recently.

• Amyloid peptides might be developed into novel antimicrobial drugs.

Supplementary information

The online version contains supplementary material available at 10.1007/s00253-022-12246-w.

Enhanced antibacterial activity of surface re-engineered lysozyme against Gram-negative bacteria without accumulated resistance

In this study, we show a way to improve the antibacterial activity of lysozyme by incorporating guanidino functional groups onto its surface (Lyz-Gua), which could treat pathogenic bacteria without accumulated resistance and shows advantages over commercial antibiotics.

Biohybrid Nanocellulose-Lysozyme Amyloid Aerogels via Electrostatic Complexation

Modern science is increasingly turning to nature for inspiration to design sustainable biomaterials in a smart and effective way. Herein, we describe biohybrid aerogels based on electrostatic complexation between cellulose and proteins-two of the most abundant natural polymers on Earth. The effects of both particle surface charge and particle size are investigated with respect to aerogel properties including the morphology, surface area, stability, and mechanical strength. Specifically, negatively charged nanocellulose (cellulose nanocrystals and cellulose nanofibers) and positively charged lysozyme amyloid fibers (full-length and shortened via sonication) are investigated in the preparation of fibrillar aerogels, whereby the nanocellulose component was found to have the largest effect on the resulting aerogel properties. Although electrostatic interactions between these two classes of charged nanoparticles allow us to avoid the use of any cross-linking agents, the resulting aerogels demonstrate a simple additive performance as compared to their respective single-component aerogels. This lack of synergy indicates that although electrostatic complexation certainly leads to the formation of local aggregates, these interactions alone may not be strong enough to synergistically improve bulk aerogel properties. Nevertheless, the results reported herein represent a critical step toward a broader understanding of biohybrid materials based on cellulose and proteins.

Necessity of regulatory guidelines for the development of amyloid based biomaterials

Amyloid diseases are caused due to protein homeostasis failure where incorrectly folded proteins/peptides form cross-β-sheet rich amyloid fibrillar structures. Besides proteins/peptides, small metabolite assemblies also exhibit amyloid-like features. These structures are linked to several human and animal diseases. In addition, non-toxic amyloids with diverse physiological roles are characterized as a new functional class. This finding, along with the unique properties of amyloid like stability and mechanical strength, led to a surge in the development of amyloid-based biomaterials. However, the usage of these materials by humans and animals may pose a health risk such as the development of amyloid diseases and toxicity. This is possible because amyloid-based biomaterials and their fragments may assist seeding and cross-seeding mechanisms of amyloid formation in the body. This review summarizes the potential uses of amyloids as biomaterials, the concerns regarding their usage, and a prescribed workflow to initiate a regulatory approach.

Wine Thermosensitive Proteins Adsorb First and Better on Bentonite during Fining: Practical Implications and Proposition of Alternative Heat Tests

Bentonite fining is the most popular treatment used to remove proteins in white and rosé wines. The usual heat test used to adjust the bentonite dose consists of heating the wine during 30 min at 80 °C. At this temperature, all of the proteins are unfolded, and this can lead to an overestimation of the dose. We have shown that proteins adsorb on bentonite in a specific order and, more importantly, that the proteins responsible for haze formation adsorb first. Fluorescence spectroscopy showed that this is due to the structural properties of proteins, which can be classified as hard and soft proteins. Alternative heat tests were performed at a lower temperature (40 °C) and showed a better correlation with accelerated aging. These tests were also less dependent upon the wine pH.

Fabrication of Composite Structures of Lysozyme Fibril-Zein using Antisolvent Precipitation: Effects of Blending and pH Adjustment Sequences

Antisolvent precipitation is a widely used method to fabricate prolamin-based composites. In the present study, composite structures of lysozyme amyloid fibrils with zein proteins were fabricated using the antisolvent precipitation method by applying different blending and pH adjustment sequences. Globular prolamins were bound to the amyloid fibrils to combine their respective advantages. The dynamic light scattering showed that the composites with a characteristic stabilized behavior (43.60 ± 1.75 mV ∼ 35.20 ± 0.65 mV) were formed at pH 4.0-5.0, in which noncovalent interactions between fibril and particles occurred. Two different structures: fruit tree-like structure and beaded-like structure, were presented in AFM and TEM images due to the different pH adjustment sequences, while blending sequences had negligible effect on the morphology of the composites. A fruit tree-like entity was detected for lysozyme fibril-zein composites, where its "branches" bear zein globular particles. A beaded-like structure was observed for lysozyme fibril-zein composites, where lysozyme fibril was the thread and zein aggregates were the beads. The potential mechanism of this phenomenon can be explained as the fruit tree-like structure being primarily formed through electrostatic interactions while the beaded-like structure is mainly caused by hydrophobic interactions. The composites of fruit tree-like structures hold a more promising stability than those with beaded-like structures. The results of this research would give constructive information for the fabrication of amyloid fibril-prolamin protein composites, which may exhibit the combined advantages of each components and have potential applications in encapsulation and protection of bioactive substances and stabilizing emulsions.

Dextran sulfate-modified pH-sensitive layered double hydroxide nanocomposites for treatment of rheumatoid arthritis

To reduce the side effects of methotrexate and increase its anti-inflammatory effect, we developed a drug delivery system, dextran sulfate-modified methotrexate-loaded layered double hydroxide nanocomposites (LDH-MTX-DS), with both targeting and pH-sensitivity for the treatment of rheumatoid arthritis. The nanocomposites had a mean particle size of 303.1 ± 8.07 nm, zeta potential of - 12.4 ± 0.7 mV, encapsulation efficiency of 49.64%, and loading efficiency of 16.81%. In vitro release experiments demonstrated that the drug was released faster in PBS at pH 5.5 than at pH 7.4, which reflected the pH-sensitivity of this system. Cellular uptake assays displayed higher cellular uptake rate of the dextran sulfate-modified targeting carrier compared with that of a non-targeting carrier (P < 0.01), which indicated that the LDH-MTX-DS could actively target scavenger receptors on the surface of activated RAW 264.7 cells. In vivo pharmacodynamic experiments showed that, after the second (P < 0.001) and third (P < 0.05) administrations, the preparation group exhibited significantly improved therapeutic efficacy in adjuvant-induced arthritis (AIA) rats when compared with free MTX alone. These results indicated that this drug delivery system was promising in the treatment of rheumatoid arthritis. Graphical abstract.

Dynamics of long hyaluronic acid chains through conical nanochannels for characterizing enzyme reactions in confined spaces

This research reports the transport behaviors of long flexible polymers (hyaluronic acid) through long conical track-etched nanochannels with and without grafted enzymes. The impacts of the channel diameter and the polymer regimes in solution (dilute and semi-dilute) have been investigated. Without enzymes, the experimental results can be well explained by the analytical models of the scaling law of de Gennes. Then, the corresponding enzymes (hyaluronidase) were grafted inside the channel. When enzymes are located at the base side, polymers get degraded at the entrance and the degraded products are detected. When enzymes are grafted at the tip side, the extension of translocation duration due to the binding of substrate-enzyme is observed. This is for the first time that the enzymatic degradation reactions are characterized in situ at the single molecule level by nanopore technology.

Core-Shell Gold Nanorod@Layered Double Hydroxide Nanomaterial with Highly Efficient Photothermal Conversion and Its Application in Antibacterial and Tumor Therapy

Photothermal conversion efficiency (η) of gold nanorods (GNRs) can be tuned by enlarging the aspect ratio and forming the core-shell structure. Herein, an easy synthesis method is developed to construct the core-shell GNR@LDH nanostructure with GNRs and layered double hydroxides (LDHs). The interaction between Au and LDHs results some electron deficiency on the surface of Au and the more electrons induce more thermal energy conversion. The η value of GNR@LDH can reach up to 60% under the 808 nm laser irradiation, which is a significant enhanced conversion efficiency compared with the reported GNR-based photothermal therapy materials. CTAB (cetyltrimethyl ammonium bromide) can be replaced totally during the synthesis process, and GNRs maintain a good dispersion in LDHs. This core-shell composite GNR@LDH can be applied in photothermal, antibacterial, tumor therapy and biological imaging with low dosage and nontoxicity.

Protein at liquid solid interfaces: Toward a new paradigm to change the approach to design hybrid protein/solid-state materials

This review gives an overview of protein adsorption at solid/liquid interface. Compared to the other ones, we have focus on three main questions with the point of view of the protein. The first question is related to the kinetic and especially the using of Langmuir model to describe the protein adsorption. The second question is about the concept of hard and soft protein. In this part, we report the protein structural modification induced by adsorption regarding their intrinsic structure. This allows formulating of a new concept to classify the protein to predict their behavior at solid/liquid interface. The last question is related to the protein corona. We give an overview about the soft/hard corona and attempt to make correlation with the concept of hard/soft protein.

Food protein amyloid fibrils: Origin, structure, formation, characterization, applications and health implications

Amyloid fibrils have traditionally been considered only as pathological aggregates in human neurodegenerative diseases, but it is increasingly becoming clear that the propensity to form amyloid fibrils is a generic property for all proteins, including food proteins. Differently from the pathological amyloid fibrils, those derived from food proteins can be used as advanced materials in biomedicine, tissue engineering, environmental science, nanotechnology, material science as well as in food science, owing to a combination of highly desirable feature such as extreme aspect ratios, outstanding stiffness and a broad availability of functional groups on their surfaces. In food science, protein fibrillization is progressively recognized as an appealing strategy to broaden and improve food protein functionality. This review article discusses the various classes of reported food protein amyloid fibrils and their formation conditions. It furthermore considers amyloid fibrils in a broad context, from their structural characterization to their forming mechanisms and ensued physical properties, emphasizing their applications in food-related fields. Finally, the biological fate and the potential toxicity mechanisms of food amyloid fibrils are discussed, and an experimental protocol for their health safety validation is proposed in the concluding part of the review.

Dual role of layered double hydroxide nanocomposites on antibacterial activity and degradation of tetracycline and oxytetracyline

The antibiotic intercalation inside the layered double hydroxide (LDH) layers was usually considered for water decontamination but rarely for drug delivery. Here, tetracycline (TCH) and oxytetracycline (OXY) were immobilized in Zn₂Al-Cl LDH following two methods: co-precipitation and anionic exchange. The interfacial concentration of antibiotic varies from 0.04 to 0.5 depending the method of immobilization. The antibiotics are not intercalated in the interlayer space allowing their release in 10 Hours. The antibacterial activity against both E. coli and S. epidermidis revealed that the loaded antibiotics are still active but less efficient compared to the free ones. After exposition to UV light or to high temperature storage (30, 60 and 120 °C), their antibacterial activity significantly decreases due to their degradation especially when antibiotic is loaded on material by co-precipitation. These results are promise to reduce antibiotic contamination in waters.

Flower-like Surface of Three-Metal-Component Layered Double Hydroxide Composites for Improved Antibacterial Activity of Lysozyme

Microbes play an important function in our lives, while some pathogenic bacteria are responsible for many infectious diseases, food safety, and ecological pollution. Layered double hydroxide (LDH) is a kind of natural two-dimensional material and has been applied in many fields. Lysozyme is a green natural antibacterial agent, while the antimicrobial activity of lysozyme is not as good as antibiotics. We use a different ratio of cations to tune the morphology of LDH covered with lysozyme to enhance the antibacterial ability of lysozyme. We synthesize MgAl-LDH, ZnAl-LDH, and ZnMgAl-LDH covered with lysozyme, characterize the structure and morphology, test the antibacterial in culture media, and evaluate the biotoxicity in vitro and in vivo. The flower-like structure of ZnMgAl-LDH has a rough surface, covered with lysozyme with a perfect ring, and presents good antibaterial properties and promotes wound healing of mice. The bloom flower structure of ZnMgAl-LDH can enhance the loading rate of lysozyme; meanwhile, the rougher surface can adhere more bacteria, so lyso@ZnMgAl-LDH presents better antibacterial activity than the binary LDHs.