Silver nanoparticle-deposited whey protein isolate amyloid fibrils as catalysts for the reduction of methylene blue

Examining the inhibitory potency of metal polyphenolic network-coated silver nanoparticles against amyloid fibrillogenesis of lysozyme

There are currently over forty degenerative diseases that are correlated with abnormal accumulation of peptide/protein aggregates in the human body, such as Alzheimer's disease. Due to their unique physiochemical properties (e.g., small size, large surface-to-volume ratio, and facile surface modification), silver nanoparticles (AgNPs) have been considered potential substrates for designing inhibitors against amyloid fibrillogenesis. Metal polyphenolic network (MPN) that combines the characteristics of organic and inorganic components has been used to suppress amyloid fibril formation. This study is aimed at investigating the effects of MPN-coated AgNPs (MPN-AgNPs) on the in vitro amyloid fibrillogenesis of hen lysozyme (HEWL). The two types of MPN-AgNPs (Zn/MPN-AgNPs and Co/MPN-AgNPs) were synthesized through chemical reduction and metal chelation, and their particle sizes were determined to be in the range of 40-60 nm. The characterization of MPN-AgNPs by ζ-potential and transmission electron microscopy showed that the MPN-AgNPs had negative surface charge and spherical-shaped morphology. Furthermore, the elemental analysis demonstrated that the MPN was uniformly coated on the surface of AgNPs. The thioflavin T fluorescence results revealed that the Co/MPN-AgNPs showed a better percent of inhibition compared to Zn/MPN-AgNPs and TA-AgNPs. The kinetics data of amyloid fibril formation in the presence of MPN-AgNPs were analyzed using the sigmoidal curve, showing that the MPN-AgNPs reduced fibril growth rate and prolonged lag time. Our findings also demonstrated that MPN-AgNPs could effectively suppress HEWL aggregation upon binding to aggregation-prone regions. The quenching of intrinsic fluorescence of HEWL by MPN-AgNPs was found to be a static type. Moreover, the fluorescence quenching data were analyzed using the modified Stern-Volmer equation to determine the number of binding sites. Notably, our findings indicated that the binding between HEWL and MPN-AgNPs was mainly governed by hydrophobic interaction. This work offers an excellent example of utilizing MPN-based materials as anti-aggregating/anti-fibrillogenic nano-drugs for the treatment of amyloidosis.

Composite biopolymer foams fabricated from natural aldehyde functionalized chitosan-whey protein amyloid fibrils: Application for removal of phthalate esters from water

In this work, composite biopolymer foams from chitosan and whey isolate protein amyloid fibrils were prepared for the removal of phthalate esters from water. Natural aldehyde functionalization enhanced the affinity for dibutyl phthalate (DBP), with citral being the most effective. The citral-grafted foams (WCGC) had tunable hydrophobicity, strong mechanical properties, and good water stability. WCGC1.5 foam exhibited a high removal efficiency (96.06 %) of DBP. The adsorption process reached adsorption equilibrium rapidly within 8 h and could be described by pseudo-second-order kinetic and Freundlich isotherm models, indicating a non-homogeneous and chemisorptive sorption process. The maximum adsorption capacity for DBP reached 332.42 mg/g. Moreover, DBP adsorption could be enhanced in alkaline environment and the removal efficiency increased to 98.27 % at pH 10. The removal efficiency of DBP by WCGC1.5 remained above 85 % after the five adsorption-desorption cycles. WCGC1.5 also showed broad-spectrum adsorption behavior, with strong affinity and removal efficiency for six common plasticizers, including DIBP (85.97 %), DPP (91.7 %), DHXP (99.1 %), DEHP (99.09 %), DNOP (91.6 %) and BBP (89.88 %).

Applications of three-dimensional whey protein amyloid fibril-based hybrid aerogels in oil/water separation and emulsion separation

Environmental contamination from oil spills and industrial wastewater poses long-term risks to ecosystems and human health. Amyloid fibrils' superior stiffness and stability, outstanding biocompatibility and biodegradability, versatile functional groups, and high specific surface area make them promising sustainable adsorbents. This study is aimed at examining the application of three-dimensional polysaccharide-modified whey protein amyloid fibril (WPIAF) aerogels in oil/water separation and emulsion separation. The WPIAF aerogel was first synthesized through the salting out method coupled with lyophilization, then modified using carboxymethyl cellulose (CMC) or chitosan (CS). Our results showed that WPIAF aerogels exhibited increased mechanical properties and surface hydrophobicity after polysaccharide modification. The CS-modified WPIAF aerogels showed better oil adsorption capacities, oil adsorption capability, and reusability than WPIAF aerogel and CMC-modified WPIAF aerogels. Furthermore, the applicability of polysaccharide-modified WPIAF aerogels in a continuous oil/water separation system was demonstrated. Finally, the separation efficiencies of polysaccharide-modified WPIAF aerogels were determined to be over 90 % in various emulsion systems, and the possible separation mechanism was further investigated. This study provides a nice example of applying amyloid-based aerogels for oil/water separation and emulsion separation.

Sustainable detergent-disinfectant agent based on whey mineralizate and silver nanoparticles for cleaner production in dairy industry

Detergents and disinfectants for dairy industry must meet a variety of characteristics, including low toxicity, high antibacterial activity, and excellent rinsing of pollutants from working surfaces. This work presents an innovative detergent-disinfectant agent based on whey mineralizate and silver nanoparticles (Ag NPs), which allows reducing production costs and ensuring high cleanliness of treated surfaces compared to analogues. For this purpose, a method for obtaining sols of Ag NPs stabilized with didecyldimethylammonium bromide (Ag NPs-DDAB) was developed and optimized using neural network algorithms. Characterization of Ag NPs-DDAB showed particles with a radius of 4.5 nm and 20 nm, stable in the pH range from 2 to 11. An acute toxicity study of Ag NPs in mice showed LD50 = 4230 μg/kg. Based on the degree of accumulation and inhalation toxicity, Ag NPs-DDAB are classified as low-hazard chemicals. The developed detergent-disinfectant had a washability of about 90%, high antimicrobial activity (0.005 mg/mL) against Penicillium roqueforti and a sanitary and hygienic effect on coliforms, general contamination and pathogenic microorganisms, a low-corrosive effect and low toxicity (315 mg/mL) to Danio rerio. It was concluded that the use of detergent-disinfectant agent will completely eliminate the consumption of water for the equipment cleaning process and can be used to clean an electrodialysis unit's circuits, enabling the utilization of secondary waste from membrane milk processing and promoting resource efficiency and cleaner production in the dairy industry.

Nanotechnology in action: silver nanoparticles for improved eco-friendly remediation

Nanotechnology is an exciting area with great potential for use in biotechnology due to the far-reaching effects of nanoscale materials and their size-dependent characteristics. Silver and other metal nanoparticles have attracted a lot of attention lately because of the exceptional optical, electrical, and antimicrobial characteristics they possess. Silver nanoparticles (AgNPs) stand out due to their cost-effectiveness and abundant presence in the earth's crust, making them a compelling subject for further exploration. The vital efficacy of silver nanoparticles in addressing environmental concerns is emphasized in this thorough overview that dives into their significance in environmental remediation. Leveraging the distinctive properties of AgNPs, such as their antibacterial and catalytic characteristics, innovative solutions for efficient treatment of pollutants are being developed. The review critically examines the transformative potential of silver nanoparticles, exploring their various applications and promising achievements in enhancing environmental remediation techniques. As environmental defenders, this study advocates for intensified investigation and application of silver nanoparticles. Furthermore, this review aims to assist future investigators in developing more cost-effective and efficient innovations involving AgNPs carrying nanoprobes. These nanoprobes have the potential to detect numerous groups of contaminants simultaneously, with a low limit of detection (LOD) and reliable reproducibility. The goal is to utilize these innovations for environmental remediation purposes.

Using silver nanoparticle-decorated whey protein isolate amyloid fibrils to modify the electrode surface used for electrochemical detection of para-nitrophenol

Due to their organized structures, remarkable stiffness, and nice biocompatibility and biodegradability, amyloid fibrils serve as building blocks for versatile sustainable materials. Silver nanoparticles (AgNPs) are commonly used as the nano-catalysts for various electrochemical reactions. Given their large specific surface area and high surface energy, AgNPs exhibit high aggregation propensity, which hampers their electrocatalytic performance. Food protein wastes have been identified to be associated with climate change and environmental impacts, and a surplus of whey proteins in dairy industries causes high biological and chemical demands, and greenhouse gas emissions. This study is aimed at constructing sustainable electrode surface modifiers using AgNP-deposited whey protein amyloid fibrils (AgNP/WPI-AFs). AgNP/WPI-AFs were synthesized and characterized via spectroscopic techniques, electron microscopy, and X-ray diffraction. Next, the electrocatalytic performance of AgNP/WPI-AF modified electrode was assessed via para-nitrophenol (p-NP) reduction combined with various electrochemical analyses. Moreover, the reaction mechanism of p-NP electrocatalysis on the surface of AgNP/WPI-AF modified electrode was investigated. The detection range, limit of detection, sensitivity, and selectivity of the AgNP/WPI-AF modified electrode were evaluated accordingly. This work not only demonstrates an alternative for whey valorization but also highlights the feasibility of using amyloid-based hybrid materials as the electrode surface modifier for electrochemical sensing purposes.

Edible nano-encapsulated cinnamon essential oil hybrid wax coatings for enhancing apple safety against food borne pathogens

Post-harvest losses of fruits due to decay and concerns regarding microbial food safety are significant within the produce processing industry. Additionally, maintaining the quality of exported commodities to distant countries continues to pose a challenge. To address these issues, the application of bioactive compounds, such as essential oils, has gained recognition as a means to extend shelf life by acting as antimicrobials. Herein, we have undertaken an innovative approach by nano-encapsulating cinnamon-bark essential oil using whey protein concentrate and imbibing nano-encapsulates into food-grade wax commonly applied on produce surfaces. We have comprehensively examined the physical, chemical, and antimicrobial properties of this hybrid wax to evaluate its efficacy in combatting the various foodborne pathogens that frequently trouble producers and handlers in the post-harvest processing industry. The coatings as applied demonstrated a static contact angle of 85 ± 1.6°, and advancing and receding contact angles of 90 ± 1.1° and 53.0 ± 1.6°, respectively, resembling the wetting properties of natural waxes on apples. Nanoencapsulation significantly delayed the release of essential oil, increasing the half-life by 61 h compared to its unencapsulated counterparts. This delay correlated with statistically significant reductions (p = 0.05) in bacterial populations providing both immediate and delayed (up to 72 h) antibacterial effects as well as expanded fungal growth inhibition zones compared to existing wax technologies, demonstrating promising applicability for high-quality fruit storage and export. The utilization of this advanced produce wax coating technology offers considerable potential for bolstering food safety and providing enhanced protection against bacteria and fungi for produce commodities.

Silver Nanoparticles for Waste Water Management

Rapidly increasing industrialisation has human needs, but the consequences have added to the environmental harm. The pollution caused by several industries, including the dye industries, generates a large volume of wastewater containing dyes and hazardous chemicals that drains industrial effluents. The growing demand for readily available water, as well as the problem of polluted organic waste in reservoirs and streams, is a critical challenge for proper and sustainable development. Remediation has resulted in the need for an appropriate alternative to clear up the implications. Nanotechnology is an efficient and effective path to improve wastewater treatment/remediation. The effective surface properties and chemical activity of nanoparticles give them a better chance to remove or degrade the dye material from wastewater treatment. AgNPs (silver nanoparticles) are an efficient nanoparticle for the treatment of dye effluent that have been explored in many studies. The antimicrobial activity of AgNPs against several pathogens is well-recognised in the health and agriculture sectors. This review article summarises the applications of nanosilver-based particles in the dye removal/degradation process, effective water management strategies, and the field of agriculture.

Application of Amyloid-Based Hybrid Membranes in Drug Delivery

The properties of amyloid fibrils, e.g., unique structural characteristics and superior biocompatibility, make them a promising vehicle for drug delivery. Here, carboxymethyl cellulose (CMC) and whey protein isolate amyloid fibril (WPI-AF) were used to synthesize amyloid-based hybrid membranes as vehicles for the delivery of cationic and hydrophobic drugs (e.g., methylene blue (MB) and riboflavin (RF)). The CMC/WPI-AF membranes were synthesized via chemical crosslinking coupled with phase inversion. The zeta potential and scanning electron microscopy results revealed a negative charge and a pleated surface microstructure with a high content of WPI-AF. FTIR analysis showed that the CMC and WPI-AF were cross-linked via glutaraldehyde and the interacting forces between membrane and MB or RF was found to be electrostatic interaction and hydrogen bonding, respectively. Next, the in vitro drug release from membranes was monitored using UV-vis spectrophotometry. Additionally, two empirical models were used to analyze the drug release data and relevant rate constant and parameters were determined accordingly. Moreover, our results indicated that in vitro drug release rates depended on the drug–matrix interactions and transport mechanism, which could be controlled by altering the WPI-AF content in membrane. This research provides an excellent example of utilizing two-dimensional amyloid-based materials for drug delivery.