Biodegradable Substrate Research Articles

Biodegradable and flexible artificial nociceptor based on Mg/MgO threshold switching memristor

As an important receptor located in the skin, a nociceptor is capable of detecting noxious stimuli and sending warning signals to the central nervous system to avoid tissue damage, thus inspiring the development of artificial nociceptors for electronic receptors. Recently, memristors have attracted increasing attention for developing artificial nociceptors due to the simplicity of the artificial nociceptive system. However, the realization of artificial nociceptors with biocompatibility and biodegradability in a single memristive device remains a challenge. Herein, a fully biocompatible and biodegradable threshold switching (TS) memristor consisting of W/MgO/Mg/W configuration was proposed as an artificial nociceptor. The device showed unidirectional TS characteristics with stable electrical performance under bending conditions. Critical nociceptor behaviors, including threshold, relaxation, no adaptation, allodynia, and hyperalgesia, were successfully demonstrated in the memristive nociceptor. Meanwhile, an optoelectronic nociceptor system was built by the integration of a photoresistor and the memristor. Importantly, the devices transferred on a biodegradable polyvinyl acetate substrate as physically transient electronics could completely dissolve in deionized water, simulating the decomposition of skin necrosis. This study provides a novel route toward developing fully biocompatible and biodegradable artificial nociceptors for promising applications in implantable and wearable electronics and secure bio-integrated systems.

Enhanced short chain fatty acids production from anaerobic fermentation of primary sludge using free ammonia pretreatment

This study is the first to report a new free ammonia (FA) pretreatment technique to recover short-chain fatty acids (SCFAs) from primary sludge (PS). The results showed FA pretreatment (240 mg N/L) largely enhanced the SCFAs production from PS to 355.8 mg chemical oxygen demand (COD)/g VSS, which was about 4.5-fold that of control (i.e., 80 mg COD/g VSS). Mechanism investigations showed that FA pretreatment greatly accelerated the PS solubilization and destroyed the integrity of EPS, and the easily biodegradable substrates in the fermentation broth increased significantly, providing microorganisms with more organics to convert into SCFAs. Further analyses displayed that FA greatly inhibited the methane production during fermentation, resulting in further accumulation of SCFAs. Given that the NH4+-N released during the fermentation can be converted into FA in situ, this could facilitate the transition of wastewater treatment plants operation from linear to circular mode.

Surface Preparation and Cytocompatibility of Three-Dimensional Printed Fully Degraded Coronary Stents Using the Plasma Polymerization Technology

Vascular stents made based on three-dimensional (3D) printing technology for interventional therapy have become one of the more common clinical means to treat patients with severe coronary heart disease (CHD). However, the biocompatibility of stent surface needs to be further improved. Over the past years, many researchers have adopted surface modification technology to improve the cytocompatibility of vascular stents. In this work, plasma polymerization (PP) technology was employed to introduce the allylamine (AA) and nitrogen with different concentrations as auxiliary gases. After ionization, fragmentation, and recombination, the surface of the stent was deposited to form amine-rich coatings (AMMak membrane and AMMak-N membrane). The composition and surface morphology of the coating were analyzed by physical characterization (infrared, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA), etc.). In addition, the cytocompatibility of the coating before and after modification was evaluated by using the endothelial cells (EC) implantation test. The biodegradable substrate (MgZnMn, Fe) was employed to deposit the amine-rich coatings and evaluate their cytocompatibility. The results told that the polymeric coating had a higher concentration of amine group when the nitrogen flow rate was at 5 sccm, and the coating was conductive to the adhesion and proliferation of ECs by adsorbing proteins. After the introduction of biodegradable substrate, the amino group on the coating surface further improved the cytocompatibility of the material. The PP technology can be applied to prepare a relatively dense PP coating, which can be further precipitated and solvent-free deposition. Therefore, it is very suitable for modifying the surface of degradable vascular stent materials.

Synthesis, Modification and Application of Polylactic Acid

Due to the increasing shortage of environmental resources, the idea of sustainable development increases the attention to the biodegradable substances. Polylactic acid (PLA) possesses outstanding mechanical and processing properties, and its products can be rapidly degraded in various ways after use. The synthesis and use of PLA have received more and more attention. Lactide, the intermediate to synthesize PLA, is challenging to produce and purify. As a result, the application cost of PLA is high, and it is hard to employ on a wide scale. Carbon dioxide (CO2) can be used for the synthesis and modification of PLA through a cell factory. It offers a wide range of potential applications and can successfully address the lactide production and purification issue. Additionally, we talked about the significance of supercritical carbon dioxide (sc-CO2) in the creation of PLA products and the viability of producing PLA directly utilizing sc-CO2 as a medium. Furthermore, we discussed how sc-CO2 affects the properties of PLA as well as the application of PLA products.

COATED POLYMERS -A REVIEW

The coating of polymers with different particles has become an important research direction due to the substantial increase in properties and implicitly the use of products in several industrial fields. The objectives of this review paper focus on polymers coating with different ceramic and metal micro particles. Thus, during the first part are presented the main methods of coating (with method detailing, advantages and disadvantages, usage materials and potential industrial applications). After this part the APS - atmospheric plasma spraying technology is detailed because it is one of the most used method. Going forward there are presented some studies from technical literature that analysed different aspects of powders coating onto biodegradable substrates (like polymer) such as structural and morphological analyses, tribological and adhesion tests, corrosion resistance, electrical conductivity, influence of process parameters and their optimization and so on. Thus, the present paper aims to briefly resum researchers' concerns on the coating of polymer-based materials, which has reached in the last period the attention due to their capability and functional applications.

Comparison of ultrasonic treatment of primary and secondary sludges: Physical properties and chemical properties

Excess sludges were by-product of sewage treatment and ultrasonic treatment was an efficient pretreatment of excess sludge. However, the difference of primary and secondary sludges treated by ultrasound unclear. This paper systematically studied the ultrasonic treatment of primary and secondary sludges, including changes of sludge particle size, sludge sedimentation, release of carbon, nitrogen, and phosphorous. These results showed that COD, TN, NH4+-N and TP in supernatant increased by 126.9 %, 76.4 %, 60.8 % and 38.5 %, respectively after ultrasonic treatment of primary sludge; and the secondary sludge was increased by 429.6 %, 66.5 %, 23.8 % and 13.7 %, respectively. After ultrasonic treatment, COD of secondary sludge increased more, and the C/N and C/P were higher. Besides, the sludge particle size was reduced from 48.42 to 9.40 μm for primary sludge, and from 41.20 to 12.46 μm for secondary sludge, respectively. That indicated ultrasound could crack sludge effectively, and the effect of secondary sludge lysis was better. Secondary sludge released more biodegradable substances with ultrasonic treatment. In addition, after ultrasonic treatment, the chemical structure of sludge changed little, but the chemical properties changed strongly, especially for the secondary sludge. That revealed ultrasound had little effect on the chemical structure of primary and secondary sludges. This paper will provide guidance in study of primary and secondary sludge with ultrasonic treatment.

Fabrication of Earth-Abundant Electrocatalysts Based on Green-Chemistry Approaches to Achieve Efficient Alkaline Water Splitting—A Review

The fabrication of earth-abundant electrocatalysts by green-chemistry approaches for electrochemical water splitting could diminish or alleviate the use or generation of hazardous substances, which could be highly desirable to achieve efficient, green alkaline water electrolysis for clean energy production (H2). This review started by introducing the importance of the green-chemistry approaches. Later, this paper reviewed the fabrication of high-performance earth-abundant electrocatalysts using green-chemistry approaches for electrochemical water splitting (HER and OER). Moreover, this review discussed the green-chemistry approaches for the fabrication of earth-abundant electrocatalysts including phosphide/pyrophosphate-, carbon-, oxide-, OH/OOH/LDH-, alloy/B/nitride-, and sulfide/selenide (chalcogenide)-based earth-abundant electrocatalysts. Moreover, this review discussed various green-chemistry approaches, including those used to alleviate toxic PH3 gas emission during the fabrication of transition-metal phosphide-based electrocatalysts, to design energy-efficient synthesis routes (especially room-temperature synthesis), to utilize cheap or biodegradable substrates, and to utilize biomass waste or biomass or biodegradable materials as carbon sources for the fabrication of earth-abundant electrocatalysts. Thus, the construction of earth-abundant electrocatalysts by green-chemistry approaches for electrochemical water splitting could pave an efficient, green way for H2 production.

Organic transformation, lactic acid metabolism, and membrane performance in high-rate methanogenic treatment of dairy processing wastewater using thermophilic high-solid anaerobic membrane bioreactor

Dairy processing wastewater (DPW) is an easily biodegradable substrate rich in lactic acid (LA) and native lactic acid bacteria (LAB), which can threaten the efficiency and stability of anaerobic treatment. This study introduced a high-solid anaerobic membrane bioreactor (AnMBR) to explore methanogenic efficiency, metabolic processes, and membrane performance in DPW treatment. A high microbial concentration rapidly realized the highest organic loading rate (OLR) of 26.3 g chemical oxygen demand (COD)/L/d with a methane yield of 317.1 ± 5.2 mL/g COD. Mass balance showed 90.6 %–98.8 % COD of DPW transferred into methane at different OLRs. A syntropic bacterium of Tepidanaerobacter syntrophicus achieved over 4.5 g/L/d LA loading rate, with relative abundance increasing from 0.36 % to 4.06 %. LAB were gradually eliminated because of unfavorable environmental conditions and high OLR. High OLR regulated methanogenesis transformation from hydrogenotrophic to mixed hydrogenotrophic and acetoclastic types. Lactic/acetic acid production was proposed as a central pathway in the metabolic process. Enhanced mixed liquor total solid concentration (20–50 g/L) limited membrane flux because of the exponentially increased sludge viscosity. Also, the colloidal particle percentage in the sludge increased from 3.5 % to 10.5 %, which promoted membrane fouling for pore blocking and cake/gel layer formation. Organic foulants dominated the membrane resistance and resulted from the high rejection efficiency of organic matter. This study showed a novel and effective approach to achieving high-rate treatment of DPW by high-solid AnMBR and provided significant guidance for the dairy industry in future wastewater treatment development.

Integration of LCA and LCC for decision making in biocomposite production

Natural fibers reinforced composites have gradually increased their application in industrial domains such as automotive, wind energy, aeronautics, etc., during the last 20 years. In a way, this is a response by the industry to global warming and the pollution of the environment and represents a shift from fossil fuel base composites to materials made of renewable, biodegradable, and recyclable substances. Life cycle assessment (LCA) is used widely in product design decision-making as an evaluation tool for environmental performance. However, it is not sufficient for profit-directed organizations to make final decisions only depending on environmental results. This study intends to evaluate the environmental impacts and the economic viability of manufacturing four different composite laminated plates reinforced with glass or flax fibers that focus on serving the needs of aircraft interiors in the early planning stage, using models for LCA and life cycle cost (LCC). The results depict that at the production stage, without taking into consideration the use stage and end-of-life, flax fiber-reinforced plates made of bio-resin as matrix material and cured using microwaves, reduce both the environmental and economic impacts, compared to their competitor, made from glass fiber-reinforced resin

The need for design-for-recycling of paper-based printed electronics – a prospective comparison with printed circuit boards

The present study compares conventional printed circuit boards (having glass-fibre and epoxy substrates and etched copper circuits) with paper-based printed electronics (offering flexible, bio-based, and biodegradable substrates with circuit design printed using silver-based inks) and assesses the relevance of e-waste recycling to the latter's sustainability. Therefore, a comparative life cycle assessment between these two options has been undertaken and the global warming impacts were calculated.The impact assessment results underscore that printed electronics offer a consistent sustainability advantage over printed circuit boards only through recycling of silver in the former at the end-of-life. Hence, design-for-recycling and recycling as e-waste are crucial to the sustainability of the current generation of printed electronics. Other foreseen waste treatment options for paper-based printed electronics, such as composting, and paper recycling, are likely to limit the sustainability advantage of printed electronics to circuits with small conductive areas.

MycelioTronics: Fungal mycelium skin for sustainable electronics.

Electronic devices are irrevocably integrated into our lives. Yet, their limited lifetime and often improvident disposal demands sustainable concepts to realize a green electronic future. Research must shift its focus on substituting nondegradable and difficult-to-recycle materials to allow either biodegradation or facile recycling of electronic devices. Here, we demonstrate a concept for growth and processing of fungal mycelium skins as biodegradable substrate material for sustainable electronics. The skins allow common electronic processing techniques including physical vapor deposition and laser patterning for electronic traces with conductivities as high as 9.75 ± 1.44 × 104 S cm-1. The conformal and flexible electronic mycelium skins withstand more than 2000 bending cycles and can be folded several times with only moderate resistance increase. We demonstrate mycelium batteries with capacities as high as ~3.8 mAh cm-2 used to power autonomous sensing devices including a Bluetooth module and humidity and proximity sensor.

Calcium peroxide and freezing co-pretreatment enhancing short-chain fatty acids production from waste activated sludge towards carbon–neutral sludge treatment

Short-chain fatty acids (SCFAs) recovery through anaerobic fermentation is a promising technology to achieve carbon–neutral in waste activated sludge (WAS) management. After 0.15 g CaO2/g volatile suspended solids (VSS) addition and three-cycle freezing co-pretreatments, the maximal SCFAs production of 438.5 mg COD/g VSS was achieved within 4 days fermentation, and more than 70 % of SCFAs was composed of acetate and propionate, which achieved a higher level than reported in previous studies. Mechanism explorations elucidated that co-pretreatment triggered sludge solubilization, promoting the release of biodegradable organics, providing more biodegradable substrates for SCFAs generation. Further microbial community analysis indicated that the abundances of hydrolytic microorganisms and acidogens were enriched, whereas methanogens were inhibited. Besides, environmental analysis suggested that co-pretreatment could achieve carbon reduction benefits of 0.116–0.291 ton CO2/ton WAS, demonstrating its huge carbon–neutral potential benefits.

Nanolaminated HfO2/Al2O3 Dielectrics for High‐Performance Silicon Nanomembrane Based Field‐Effect Transistors on Biodegradable Substrates (Adv. Mater. Interfaces 32/2022)

Biodegradable Field-Effect Transistors High-performance transient field-effect transistors and capacitors are demonstrated by integrating HfO2/Al2O3 high-k bilayers on the transferred silicon nanomembranes and utilizing PLGA-gelatin-chitosan biodegradable substrates, as reported by Chen Liu, Zhuofan Wang, Yuming Zhang, and co–workers in article number 2201477. The developed transistors exhibit record-high electron mobility, high on/off ratio and on-state current. Accelerated soaking tests reveal the biodegradation kinetics of the transient devices, which are beneficial for precise control of the functional lifetimes.

Plasma Deposition to Improve Barrier Performance of Biodegradable and Recyclable Substrates Intended for Food Packaging

The extensive application of biodegradable polymers in the food packaging industries was partially limited due to poor barrier performances. In the present work, we investigated the improvement of oxygen barrier performances by means of the deposition of a few nanometres of SiOx coatings on Poly(butylene succinate) (PBS) films. The coated samples produced by the plasma-enhanced chemical vapor deposition technique were tested in terms of morphology and composition of the surface and barrier properties. Barrier performances studied as a function of SiOx thickness were greatly improved and a reduction of at least 99% was achieved for oxygen transmission rate. In order to reduce the formation of residual stress between PBS substrate and SiOx coatings, a proper buffer layer (silicon organic SiOxCyHz) was used.

Enhanced Methane Production from Sludge Anaerobic Digestion with the Addition of Potassium Permanganate.

This work aims to reveal the effect of potassium permanganate (KMnO4) on the sludge anaerobic digestion process, as well as the relevant mechanisms. Experimental data showed that the biomethane production was gradually increased from 159.3 ± 3.0 to 211.5 ± 5.1 mL/g VSS (volatile suspended solids) when the KMnO4 content was increased from 0 to 0.08 g/g VSS, with an increasing rate of 32.8%. A further increase in the KMnO4 dosage however resulted in the decline of the methane yield. First-order kinetic model analysis indicated that higher methane production potentials and hydrolysis rates were achieved in KMnO4-added reactors than in the control. Mechanism analysis demonstrated that KMnO4 not only efficiently disintegrated the sludge flocs, which resulted in the increased contents of dissolved organics, but also enhanced the proportion of biodegradable substances in the sludge liquor. Meanwhile, the biodegradabilities of recalcitrant humus and lignocellulose substances were found to be promoted by KMnO4 treatment as higher methane yields were attained from KMnO4-treated model substrates. 16S rRNA analysis illustrated that the functional microbes participated in anaerobic digestion were largely enriched in the KMnO4-pretreated digestor. Furthermore, efficient inactivation of the fecal coliform was achieved by KMnO4 pretreatment.

Enhanced anaerobic digestion of waste activated sludge with periodate-based pretreatment

The potential of periodate (PI) in sludge anaerobic digestion is not tapped, although it has recently attracted great research interest in organic contaminants removal and pathogens inactivation in wastewater treatment. This is the first work to demonstrate significant improvement in methane generation from waste activated sludge (WAS) with PI pretreatment and to provide underlying mechanisms. Biochemical methane potential tests indicated that methane yield enhanced from 100.2 to 146.3 L per kg VS (VS, volatile solids) with PI dosages from 0 to 100 mg per g TS (TS, total solids). Electron spin resonance showed PI could be activated without extra activator addition, which might be attributed to the native transition metals (e.g., Fe2+) in WAS, thereby generating hydroxyl radical (•OH), superoxide radicals (•O2−), and singlet oxygen (1O2). Further scavenging tests demonstrated all of them synergistically promoted WAS disintegration, and their contributions were in the order of •O2− > •OH > 1O2, leading to the release of substantial biodegradable substances (i.e., proteins and polysaccharides) into the liquid phase for subsequent biotransformation. Moreover, fluorescence and ultraviolet spectroscopy analyses indicated the recalcitrant organics (especially lignocellulose and humus) could be degraded by reducing their aromaticity under oxidative stress of PI, thus readily for methanogenesis. Microbial community analysis revealed some microorganisms participating in hydrolysis, acidogenesis, and acetoclastic methanogenesis were enriched after PI pretreatment. The improved key enzyme activities and up-regulated metabolic pathways further provided direct evidence for enhanced methane production. This research was expected to broaden the application scope of PI and provide more diverse pretreatment choices for energy recovery through anaerobic digestion.

CHITOSAN AND AMINO ACIDS-COATED NANOPARTICLES POSITIVELY ALTERED ATROPINE ACCUMULATION, THE GENE EXPRESSION OF Tropinone reductase 1 AND THE YIELD OF Datura innoxia MILL

Two consecutive seasons (2020 and 2021) were held for cultivating Datura innoxia Mill as a medicinal plant for increasing the production of seeds and active ingredients as a native goal for our economy by using several aspects of chitosan (bulky and nanoparticles) as a biocompatible and biodegradable substance because of its crustacean origin and amino acids (individually and loaded onto chitosan nanoparticles). Data showed that formulated chitosan nanoparticles 100 mg/L loaded with methionine 40 mg/L gave an excellent record of fruit number per plant and seed weight per plant, and the highest protein content combined with the lowest range of the toxic compound malondialdehyde. Additionally, applying chitosan nanoparticles 50 mg/L coated with methionine 40 mg/L to D. innoxia plants resulted in the highest accumulation of atropine alkaloid and several polypeptides in the protein electrophoresis (SDS PAGE) when compared with control. Furthermore, in the roots of D. innoxia, where tropane alkaloids are synthesized, this application induced the expression of the tropinone reductase 1 (DiTR1) gene, a key gene in the synthesis of tropane alkaloids. So, the target of using nanotechnology applications (chitosan nanoparticles functionalized with methionine) in agriculture, especially medicinal plants, to increase yield and secondary metabolites has proven helpful, according to our findings. Future biological studies for these treatments are recommended, in order to test their safety on plants and humans.

Vermicomposting via Precomposting of Eucalyptus Leaves for Proper Waste Management and Sustainable Agriculture Growth

ABSTRACT Eucalyptus plants are found to be located in a variety of places such as low rainfall areas, schools, colleges, and government hospitals. The leaves remain fallen beneath the plants for several months, as they contain a variety of phenolic compounds and terpenes, which are responsible for its multipurpose properties, such as antifungal, antibacterial, analgesic and anti-inflammatory. Out of this 1.8 cineol is found to be major constituent and responsible for inhibiting microbial growth, which is a prime requirement of biological waste degradation and composting. To fasten the degradation process, the phenolic compounds were isolated smoothly by grinding the eucalyptus leaves, followed by extraction with hot boiling water, precomposting of residue with available garden soil and water from bio-reactor of effluent treatment plant (ETP), instead of cow dung and then vermicomposting. This process was found to be cost-effective, giving better quality of vermicompost with good carbon-to-nitrogen (C/N) ratio, macro- and micronutrients for valuable soil amendment and sustainable agriculture growth. The process was found to be user-friendly, eco-friendly, sustainable and could be used for available substrates with possible pre-treatment. The process could be converted from conventional batch process to continuous process by the technique of precomposting with carbon- and nitrogen-rich biodegradable substrates. Physico-chemical analysis techniques such as electrical conductivity, pH, humification index, FT-IR spectroscopic technique and C/N ratio are found to be comparatively easy, fast, and effective techniques for monitoring vermicomposting process as well as determining completion, quality, and stability of vermicompost produced.

Safety and efficacy of a feed additive consisting of glyceryl polyethyleneglycol ricinoleate (PEG castor oil) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of glyceryl polyethyleneglycol ricinoleate (PEG castor oil) as technological feed additive for all animal species. PEG castor oil is safe at a maximum concentration in complete feed of 90mg/kg for chickens for fattening and other minor growing poultry; 134mg/kg for laying hens and other laying/breeding birds kept for egg production/reproduction; 121mg/kg for turkeys for fattening; 162mg/kg for piglets and other minor growing Suidae; 194mg/kg for pigs for fattening; 236mg/kg for sows other minor reproductive Suidae; 231mg/kg for dairy cows and other dairy ruminants (other than sheep/goats); 142mg/kg in rabbits and 377mg/kg in veal calves; 356mg/kg for cattle for fattening and other growing ruminants, sheep, goat, horses and cats; 427mg/kg for dogs; 407mg/kg for salmonids and other fin fish; and 1,584mg/kg for ornamental fish. For other growing species and non-food producing animals, the additive is considered safe at 90mg/kg complete feed. The use of PEG castor oil as feed additive for all animal species would be of no concern for the consumer. The FEEDAP Panelconsidered inhalation exposure of the user to the additive unlikely. PEG castor oil is not considered a skin sensitiser. The panel was not in the position to conclude on the potential of the additive to be a skin or eye irritant. The additive is a readily biodegradable substance and is not expected to pose a risk for the environment. The lack of sufficient data does not allow the FEEDAP Panelto conclude on the efficacy of PEG castor oil as an emulsifier in feedingstuffs.

Removal of detergents in car wash wastewater by sub-surface flow constructed wetland

Suspended substances in car washes can often be easily removed by physicochemical processes. The main problem is to remove dissolved substances such as detergents from the water. In this study, a biodegradable substance Sodium Lauryl Sulfate (SLS) was removed from the car wash wastewater by the use of Phragmites australis in the subsurface constructed wetland. For this study, 4 plexiglass reactors having an effective volume of 10.8 L with the dimensions of 15cm×45cm×20 cm were used. The experiments were conducted with vegetation which was called SCW and without vegetation which was named control group (CG), as two groups. A serial connection of two reactors was performed for each group. Up to 90% detergent removal was observed with the vegetation in the SCW with a loading rate of 75 L/(m2.d) The effluents quality showed that the treated water can be reused carwash or irrigation for landscaping.