Denaturation Of Enzyme Research Articles

Epoxy Vitrimer Materials by Lipase-Catalyzed Network Formation and Exchange Reactions.

The preparation and reprocessing of an epoxy vitrimer material is performed in a fully biocatalyzed process wherein network formation and exchange reactions are promoted by a lipase enzyme. Binary phase diagrams are introduced to select suitable diacid/diepoxide monomer compositions overcoming the limitations (phase separation/sedimentation) imposed by curing temperature inferior than 100 °C, to protect the enzyme. The ability of lipase TL, embedded in the chemical network, to catalyze efficiently exchange reactions (transesterification) is demonstrated by combining multiple stress relaxation experiments at 70-100 °C and complete recovery of mechanical strength after several reprocessing assays (up to 3 times). Complete stress relaxation ability disappears after heating at 150 °C, due to enzyme denaturation. Transesterification vitrimers thus designed are complementary to those involving classical catalysis (e.g., using the organocatalyst triazabicyclodecene) for which complete stress relaxation is possible only at high temperature.

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.

Denaturation of proteins under the influence of ultrasound. Hypothesis

In the food industry, the use of ultrasound as a non-thermal treatment is expanding. Ultrasound is often used at the final stage of food production to improve rheological characteristics and prolong shelf life. However, an increase in temperature during ultrasonic treatment can negatively affect the quality of the final product. An increase in temperature during food processing causes the denaturation of enzymes. For most enzymes of animal origin, the denaturation temperature is 40-50 °C, and for enzymes of plant origin it is 50-60 °C. At the same time, at a temperature of 80 °C and above, all enzymes are destroyed. In this regard, it was very important to investigate possible temperature changes during ultrasonic treatment. The essence of the hypothesis put forward by “Shoman” is the study of the fact that during ultrasonic treatment, thermal effects occur, at which protein denaturation begins. An increase in the temperature values during ultrasonic treatment above the denaturation temperature of proteins confirms our hypothesis. It is established that: 1) with ultrasonic exposure to a two-component oil/ water emulsion, the temperature rises to 83 °C with a duration of exposure of 28 minutes; 2) an increase in the proportion of oil relative to water contributes to an increase in temperature from 74 to 83 °C; 3) with equal oil/water ratios, the content of mineral salts and organic substances in drinking water contributes to an increase in temperature under ultrasonic exposure compared to distilled water. The results obtained are valid for a two-component water-oil emulsion. It is of interest to study the influence of other food components on the dynamics of temperature changes during ultrasonic treatment. I would like to know the opinion of other researchers on the “Shoman” hypothesis.

Review on microbially synthesized nanoparticles: a potent biocontrol agent against Aedes species of mosquito

Aedes aegypti is a principal vector of dengue, chikungunya and Zika illnesses worldwide. Because effective vaccinations or medications for the prevention and/or treatment for these illnesses are not available, vector management has been embraced as the primary method of reducing their transmission. The strategy that is often used for controlling Aedes populations is chemical insecticides; however, despite their efficiency, extensive usage of these pesticides has resulted in high operating costs, the establishment of resistant populations and undesirable non-target impacts. Therefore, the use of nanoparticles derived from multiple synthesis processes as new insecticides has recently attracted the interest of researchers. This study provides an overview of the current understanding concerning the method of action of nanoparticles against mosquitoes. Metal nanoparticles strongly influence antioxidant and detoxifying enzymes in insects, causing oxidative stress and cell death. These nanoparticles similarly inhibited acetylcholinesterase activity. Metal-based nanoparticles can potentially bind to S and P units in proteins and nucleic acids respectively resulting in decreased membrane permeability, organelle and enzyme denaturation which leads to cell death. Furthermore, they upregulate and downregulate critical insect genes, lower protein synthesis and gonadotrophin release, resulting in developmental and reproductive failure. This review critically examines insect nanotoxicology research trends and highlights the ecotoxicological effects of practical usage of nanoparticles as insecticides.

Nanocellulose coated paper diagnostic to measure glucose concentration in human blood.

A new generation of rapid, easy to use and robust colorimetric point of care (POC) nanocellulose coated-paper sensors to measure glucose concentration in blood is presented in this study. The cellulose gel containing the enzyme with co-additive is coated and dried onto a paper substrate. Nanocellulose gel is used to store, immobilize and stabilize enzymes within its structure to prolong enzyme function and enhance its availability. Here, we immobilize glucose oxidase within the gel structure to produce a simple colorimetric blood glucose sensor. Increase in blood glucose concentration increases the concentration of reaction product which decreases the system pH detected by the pH indicative dye entrapped in the nanocellulose gel. The sensor produces a color change from red to orange as pH decreases due to the enzymatic reaction of glucose into gluconic acid and hydrogen peroxide. This sensor can measure glucose concentrations of 7-13mM (medical range for diabetes control) at temperatures of 4°C-40°C. Stability tests confirm that no denaturation of enzyme occurs by measuring enzyme activity after 4weeks. A prototype device is designed to instantly measure the glucose concentration from blood in a two steps process: 1) red blood cell separation and 2) quantification of glucose by color change. This study demonstrates nanocellulose sensor as an economical, robust, and sensitive diagnostic technology platform for a broad spectrum of diseases.

Mechanochemistry-guided reticular assembly for stabilizing enzymes with covalent organic frameworks

Structural stabilization of enzymes by porous frameworks is an emerging strategy in biotechnology that may accelerate large-scale industrial application of biocatalysts. Herein, we stabilize an enzyme by wrapping it with covalent organic frameworks in situ using a mild mechanochemistry-guided assembly. This mechanochemical strategy circumvents the harsh conditions often necessary for covalent organic frameworks’ crystallization, and hence avoids enzyme denaturation during the de novo encapsulation. The covalent-linked topology and tailorable large pore channels of the covalent organic framework host not only stabilize enzymes, but also outperform the well-explored enzyme-zeolite imidazole framework counterparts in terms of catalytic efficiency, functional diversity, and structural stability. This work offers a greener and convenient mechanochemistry-guided assembly strategy, enabling template-free enzyme encapsulation across multiple enzyme and covalent organic framework pore structures. • A mechanochemical strategy for engineering enzyme-COFs biohybrids is reported • The mechanochemical method is demonstrated across multiple enzymes and COFs • The enzyme-encapsulated COFs are structurally stable and catalytically active Immobilization of enzymes without disrupting their function is an important component of biocatalysis. Here, Gao et al. report a mechanochemistry-guided assembly strategy for bottom-up construction of enzyme-encapsulated covalent organic framework biocomposites.

Agro-Industrial Food Waste as a Low-Cost Substrate for Sustainable Production of Industrial Enzymes: A Critical Review

The grave environmental, social, and economic concerns over the unprecedented exploitation of non-renewable energy resources have drawn the attention of policy makers and research organizations towards the sustainable use of agro-industrial food and crop wastes. Enzymes are versatile biocatalysts with immense potential to transform the food industry and lignocellulosic biorefineries. Microbial enzymes offer cleaner and greener solutions to produce fine chemicals and compounds. The production of industrially important enzymes from abundantly present agro-industrial food waste offers economic solutions for the commercial production of value-added chemicals. The recent developments in biocatalytic systems are designed to either increase the catalytic capability of the commercial enzymes or create new enzymes with distinctive properties. The limitations of low catalytic efficiency and enzyme denaturation in ambient conditions can be mitigated by employing diverse and inexpensive immobilization carriers, such as agro-food based materials, biopolymers, and nanomaterials. Moreover, revolutionary protein engineering tools help in designing and constructing tailored enzymes with improved substrate specificity, catalytic activity, stability, and reaction product inhibition. This review discusses the recent developments in the production of essential industrial enzymes from agro-industrial food trash and the application of low-cost immobilization and enzyme engineering approaches for sustainable development.

The Investigation of the Effects of Different Seminal Plasma Heating Processes on Short Term Storage of the Akkaraman Kangal Ram Sperm

Bu araştırma, koç spermasında bulunan seminal plazmanın, spermler üzerindeki etkisini incelemek ve reprodüktif açıdan kullanımını değerlendirmek amacıyla yapılmıştır. Araştırma için, 24-36 aylık yaşlarda, 8 adet ergin koçtan alınan spermalar kullanılmıştır. Spermalar çiftleşme mevsimi dışında olan koçlardan elektro ejekülatör yardımı ile alınmıştır. Spermalar seminal plazmalarından santrifüj edilerek ayrılıp, 60 ⁰C'lik ve 80 ⁰C'lik 10 dakikalık ısıtma işleminden geçirilmiştir. 60 ⁰C'lik ve 80 ⁰C'lik gruplar ile hiçbir işlem uygulanmayan kontrol gurubu 4 ⁰C'lik ortamda bekletilmeye alınmıştır. Ortalama 8 saatte bir kontrol edilen 3 grupta gözlenen motilite, canlı/ölü oranı ve spermatazoon anormallikleri kaydedilmiştir. Araştırmadan elde edilen sonuçlara göre, kontrol grubu ve deneme grupları karşılaştırıldığında en uzun süre canlılık ve motilitenin 80 ⁰C'lik grup olduğu belirlenmiştir. Bu sonuca göre spermanın seminal plazmasının içerisinde bulunan çeşitli proteinlerin ve enzimlerin denatürasyonu ile yaşam süresinin, normal spermatazoon oranının ve motilitenin doğru orantılı bir şekilde arttığını kanıtlar niteliktedir.

Relationship between intracellular protein denaturation and irreversible inactivation of Saccharomyces pastorianus by low-pressure carbon dioxide microbubbles.

To clarify the relationship between irreversible inactivation and intracellular protein denaturation of Saccharomyces pastorianus by low-pressure carbon dioxide microbubbles (CO2 MB) treatment, a storage test of S. pastorianus cells treated with CO2 MB was performed, and the effect on the intracellular protein was investigated. In the storage test, the S. pastorianus population, which decreased below the detection limit by CO2 MB treatment at a temperature of 45 and 50°C (MB45 and MB50), and thermal treatment at a temperature of 80°C (T80), remained undetectable during storage for 3 weeks at 25°C. However, 4.1 and 1.3-logs of the S. pastorianus populations, which survived after CO2 MB treatment at temperatures of 35 and 40°C (MB35 and MB40), increased gradually during storage for 3 weeks at 25°C. Insolubilization of intracellular proteins in S. pastorianus increased with increasing the temperature of CO2 MB treatment. Activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) identified as one of the insolubilized proteins increased at MB35 and MB40 than non-treatment but disappeared at MB45 and MB50, and T80. Therefore, it was revealed that S. pastorianus cells inactivated below the detection level by CO2 MB treatment did not regrow and that the denaturation of intracellular proteins of S. pastorianus was caused by CO2 MB and thermal treatments. Furthermore, it was suggested that denaturation of intracellular vital enzymes was an important factor for achieving irreversible inactivation of S. pastorianus by CO2 MB and thermal treatments.

Laccase Cross-Linked Ultraporous Aluminas for Sustainable Biodegradation of Remazol Brilliant Blue R

Over the past few decades, enzyme-based green and sustainable chemistry has attracted extensive research attention, which provides a promising alternative to the conventional treatment methods of recalcitrant micropollutants. However, enzyme denaturation and stability loss remain critical challenges for its potential applications in industrial wastewater treatment. In this study, laccase from Trametes versicolor (laccase T.) was cross-linked immobilized by ultraporous alumina (UPA) for the sustainable biodegradation of Remazol Brilliant Blue R (RBBR). Through sequential use of an aminosilane coupling agent (3-aminopropyl)triethoxysilane (APTES) and bifunctional cross-linker glutaraldehyde (GA), the synthesized biocatalysts showed better immobilization performances (about 4-fold to physical adsorption). The GA concentration considerably affected the laccase T. cross-linking degree, while the GA post-treatment protocol showed the highest laccase T. immobilization yield with lower activity recovery. Moreover, the biocatalyst stabilities including pH stability, thermal stability, storage stability, and reusability were also studied. Tolerance to broader pH and temperature ranges, better storage stability, good reusability of laccase T. cross-linked UPA(γ) biocatalysts, and their continuous RBRR biodegradation efficiency highlight the potentials of enzyme-based inorganic materials in industrial wastewater treatment, which can broaden our understanding of their practical applications in environmental fields.

Chemical and Sensory Characteristics of Fruit Juice and Fruit Fermented Beverages and Their Consumer Acceptance

Recent social, economic, and technological evolutions have impacted consumption habits. The new consumer is more rational, more connected and demanding with products, more concerned with the management of the family budget, with the health, origin, and sustainability of food. The food industry over the last few years has shown remarkable technological and scientific evolution, with an impact on the development and innovation of new products using non-thermal processing. Non-thermal processing technologies involve methods by which fruit juices receive microbiological inactivation and enzymatic denaturation with or without the direct application of low heat, thereby lessening the adverse effects on the nutritional, bioactive, and flavor compounds of the treated fruit juices, extending their shelf-life. The recognition of the nutritional and protective values of fruit juices and fermented fruit beverages is evident and is attributed to the presence of different bioactive compounds, protecting against chronic and metabolic diseases. Fermentation maintains the fruit's safety, nutrition, and shelf life and the development of new products. This review aims to summarize the chemical and sensory characteristics of fruit juices and fermented fruit drinks, the fermentation process, its benefits, and its effects.

ANALYSIS OF TECHNICAL AND TECHNOLOGICAL EQUIPMENT PROCESSES OF EXPANDED FEED PREPARATION

Extruders and expanders belong to the family of HTST (high temperature short-term) equipment capable of performing the task of cooking food and feed under high pressure. Because the effects of high temperatures occur only for a short time, the undesirable effects of denaturation of proteins, amino acids, vitamins, starch and enzymes are limited. Physical and technological aspects such as heat transfer, mass transfer, pulse transfer, temperature time have a strong influence on the properties of food and feed during extrusion and expanded cooking and can significantly affect the quality of the final product. The aim of the research is to analyze the technical and technological equipment of extrusion and expanded feed preparation processes and substantiate the feasibility of using expanders. The use of expanders in the feed pellet processing line has many advantages, the most important of which are: improved feed nutrition (better feed conversion); more efficient use of low-quality raw materials or even waste; sterilization of bacteriologically contaminated materials; better control of liquid additives; reduction of energy consumption of pellet press; increasing the productivity of the pellet press; expanding the product range; the possibility of using fibrous materials; reduction of dust emissions and losses during granulation. The economic and food aspects of the use of expanders make their use understandable and justified in the feed industry. The use of an expander-granulator kit increases the cost of production by 10-15 % compared to granulation alone. However, the overall income and expenditure account is positive due to the qualitative results that offset the costs incurred. The use of expanders in the global feed industry is growing every year, which is also reflected in the wider range of recently produced animal feed. The benefits of this technique are beginning to be appreciated in underdeveloped countries. Its usefulness is fully confirmed by feed manufacturers who have already implemented the above production methods.

Insight into immobilization efficiency of Lipase enzyme as a biocatalyst on the graphene oxide for adsorption of Azo dyes from industrial wastewater effluent

Immobilization of enzymes improves their stability, performance, reusability, and recovery. This study investigated the removal of Azo dyes from industrial wastewater effluent using immobilized Lipase enzyme on Graphene Oxide (GO) in batch mode. The Lipase enzyme extracted from Porcine Pancreas was immobilized onto the GO via adsorption, where the enzymes are attached to the support by intermolecular forces. This study aims to investigate the immobilization efficiency of Lipase on the GO and determine the effect of parameters such as Lipase concentration, pH, and temperature on the enzyme activity. The results showed that the enzyme activity increased with the Lipase concentration, pH and temperature until an optimum point was achieved. The saturation of support surface pores causes the loss of enzyme activity due to the excessive Lipase enzyme, structural deformation of the support surface and enzyme denaturation due to extreme pH and temperature. The immobilized Lipase activity and free Lipase activity were compared. The optimum Lipase concentration is 6 mg/mL, with the greatest immobilization efficiency and highest enzyme activity. Besides, the optimum pH for the highest immobilized Lipase activity is 8.0, and the optimum temperature is 40 °C. The characterization results confirmed the immobilization of the Lipase enzyme. Adsorption isotherm and kinetic studies are also carried out to investigate the dye removal performances. The highest Azo dye removal efficiency obtained is 89.47% at 240 min of contact time and 5 mg/L of initial dye concentration. Further, the reusability of the immobilized Lipase was also investigated and found that the immobilized Lipase can be reused up to four cycles. Thus, the adsorption of dyes through immobilized lipase on GO can significantly impact various industrial sectors.

Ultrasonication Assisted Catalytic Transesterification of Ceiba Pentandra (Kapok) Oil Derived Biodiesel Using Immobilized Iron Nanoparticles

The embedded immobilized enzymes (Rhizopus-oryzae) on the magnetic nanoparticles (Fe3O4-NPs) is a new application for the sustainable production of high-quality biodiesel. In this study, biodiesel is derived from Kapok oil via ultrasonication (US)-assisted catalytic transesterification method. A novel attempt is made to prepare magnetic nanoparticles embedded by an immobilized enzyme to solve the problem of enzyme denaturation. This innovative method resulted in optimum biodiesel conversion of 89 ± 1.17% under reactant molar ratio (methanol: oil) of 6:1, catalyst loading 10 wt% with a reaction time of 4 h at 60 °C. The kinetic and thermal study reveals that conversion of Kapok oil to biodiesel follows a pseudo first-order reaction kinetic with a lower ΔE of 30.79 kJ mol−1. The ΔH was found to be 28.06 kJ mol−1 with a corresponding ΔS of −237.12 J mol−1 K−1 for Fatty Acid Methyl Ester formation. The ΔG was calculated to be from 102.28 to 109.40 kJ mol−1 for temperature from 313 K to 343 K. The positive value of ΔH and ΔG is an indication of endothermic and non-spontaneous reaction. A negative ΔS indicates the reactant in the transition state possesses a higher degree of ordered geometry than in its ground state. The immobilized catalysts provided great advantages towards product separation and efficient biodiesel production. Highlights: 1. Effective catalytic transesterification assisted by the ultrasonication method was used for bi-odiesel production. 2. Magnetite nanoparticles synthesized by the co-precipitation method were used as heteroge-neous catalysts. 3. An immobilized enzyme (Rhizopus-oryzae) was embedded in the heterogeneous catalyst, as it is reusable and cost-effective. 4. The maximum biodiesel yield obtained from Kapok oil was 93 ± 1.04% by catalytic trans-esterification reactions.

Симуляція процесу експандованого приготування кормів

Expanded feed preparation is carried out on the appropriate high-temperature short-term equipment of the HTST family - expanders, which are able to perform the task of cooking food and feed under high pressure. In addition to the chemical processes that occur during expansion (denaturation of proteins, amino acids, vitamins, starch and enzymes), there is a change in the physical and mechanical properties of feed components and their transformation into expands. From the point of view of process physics, the process of expander formation in the expander is reduced to pressing a mixture of solid (grain components), liquid (in the form of moisture) and gaseous (vapor) phases by a screw working body through a forming nozzle under the action of an external heat source. From the point of view of mathematical description, this process is complex and therefore can be described by computer simulation. Analyzing the capabilities of these software packages for the task of simulating the formation of agglomerates (expanders) in the expander was chosen Star CCM +. The simulation of the process of expanded feed preparation in the software package Star CCM + provides the prerequisites for justifying the range of rational parameters of the expander. The simulation of the expander operation allows to determine as research criteria: the pressure in the cavity between the screw and the cylinder of the expander, the density of the obtained expands, the performance of the expander, the temperature scalar field and the velocity field vector of the multiphase mixture. As research factors should be chosen: the phase ratio of the multiphase mixture, the speed of rotation of the screw, the temperature of the heater, diameter, length and pitch of the screw.

CO2-responsive Pickering emulsions stabilized by soft protein particles for interfacial biocatalysis.

Pickering emulsions are emulsions stabilized by colloidal particles and serve as an excellent platform for biphasic enzymatic catalysis. However, developing simple and green strategies to avoid enzyme denaturation, facilitate product separation, and achieve the recovery of enzyme and colloidal particle stabilizers is still a challenge. This study aimed to report an efficient and sustainable biocatalysis system via a robust CO2/N2-responsive Pickering oil-in-water (o/w) emulsion stabilized solely by pure sodium caseinate (NaCas), which was made naturally in a scalable manner. The NaCas-stabilized emulsion displayed a much higher reaction efficiency compared with conventional CO2/N2-responsive Pickering emulsions stabilized by solid particles with functional groups from polymers or surfactants introduced to tailor responsiveness, reflected by the fact that most enzymes were transferred and enriched at the oil–water interface. More importantly, the demulsification, product separation, and recycling of the NaCas emulsifier as well as the enzyme could be facilely achieved by alternatively bubbling CO2/N2 more than 30 times. Moreover, the recycled enzyme still maintained its catalytic activity, with a conversion yield of more than 90% after each cycle, which was not found in any of the previously reported CO2-responsive systems. This responsive system worked well for many different types of oils and was the first to report on a protein-based CO2/N2-responsive emulsion, holding great promise for the development of more sustainable, green chemical conversion processes for the food, pharmaceutical, and biomedical industries.

The application of image processing for Human-Computer Interface (HCI) using the Eye

The field of Human-Computer Interaction (HCI) has been developing tremendously since the past decade. The existence of smartphones or modern computers is already a norm in society these days which utilizes touch, voice and typing as a means for input. To further increase the variety of interaction, human eyes are set to be a good candidate for another form of HCI. The amount of information which the human eyes contain are extremely useful, hence, various methods and algorithm for eye gaze tracking are implemented in multiple sectors. However, some eye-tracking method requires infrared rays to be projected into the eye of the user which could potentially cause enzyme denaturation when the eye is subjected to those rays under extreme exposure. Therefore, to avoid potential harm from the eye-tracking method that utilizes infrared rays, this paper proposes an image-based eye tracking system using the Viola-Jones algorithm and Circular Hough Transform (CHT) algorithm. The proposed method uses visible light instead of infrared rays to control the mouse pointer using the eye gaze of the user. This research aims to implement the proposed algorithm for people with hand disability to interact with computers using their eye gaze.

Nonenzymatic Electrochemical Sensor Based on CuO-MgO Composite for Dopamine Detection

Dopamine plays an essential role in the proper functioning of the brain and the body. A change in the level of dopamine can lead to disorders related to the nervous system. Thus, detection of dopamine levels may aid in the diagnosis and treatment of various diseases. Enzymatic electrochemical sensors have been extensively studied for the detection of dopamine because they exhibit excellent selectivity and reliability. However, enzymatic electrochemical sensors suffer from several unavoidable drawbacks such as complex enzyme purification process, weak enzyme immobilization on the electrode, enzyme denaturation and low stability. On the other hand, non-enzymatic sensors are promising alternatives that offer high sensitivity, high electrocatalytic activity, long term stability and eliminate the problems associated with enzymes. Herein, we present a non-enzymatic nanocomposite (NC) of metal oxides (CuO-MgO) for efficient electrochemical detection of dopamine. Scalable sol-gel method is adopted for the controlled growth of CuO-MgO NC. The structural, elemental and morphological analysis is performed by XRD, Raman spectroscopy, and TEM characterization, respectively. The electrochemical analysis was carried out to study the electrocatalytic behavior of CuO-MgO in the detection of dopamine, by cyclic voltammetry and chronoamperometric methods. The electrocatalytic behavior was investigated at different scan rates and for different dopamine concentrations in artificial sweat solution. The CuO-MgO NC catalyst exhibited a sensitivity of <inline-formula> <tex-math notation="LaTeX">$69~\mu $ </tex-math></inline-formula>Acm^&#x2212;2mM^&#x2212;1 and the detection limit is computed to be <inline-formula> <tex-math notation="LaTeX">$6.4~\mu \text{M}$ </tex-math></inline-formula> in the linear range of 10-<inline-formula> <tex-math notation="LaTeX">$100~\mu \text{M}$ </tex-math></inline-formula>. Moreover, the NC apprehended a high degree of selectivity towards other bio-compounds present in the sweat, and no possible interfering cross-reaction from these species was observed. The as-synthesized CuO-MgO NC offered high sensitivity, selectivity, fast response and stability, which benchmarked its potential for dopamine sensing.

Inactivation of Escherichia coli O157:H7 in apple juice via induced electric field (IEF) and its bactericidal mechanism

Non-conventional heating technology based on electric fields can be utilized to process liquid foods. In this study, the induced electric field (IEF) was investigated to clarify its inactivation mechanism on E.coli. Staining results show that inactivation of E.coli by IEF can be attributed to the reversible destruction of the cell membrane, followed by the denaturation of intracellular enzymes, and finally the irreversible rupture of the cell membrane. The increased levels of extracellular proteins and nucleic acids were also observed. IEF treatment at 400 Hz and 800 V (or 53 V/cm) results in a reduction of 4.5 log CFU·mL−1 in the number of E.coli. Storage life analysis shows that IEF treatment can improve the stability of apple juice and the content of bioactive components. Thus, IEF is a potential technique for liquid food processing.

Needle-like Co3O4 nanoarrays as a dual-responsive amperometric sensor for enzyme-free detection of glucose and phosphate anion

The high cost and easy denaturation of natural enzymes under environmental conditions largely hinder their practical usefulness in sensing devices. Currently, great efforts have been focused on exploring of novel functional nanomaterials to replace natural enzymatic systems. In this study, we developed a hydrothermal growth of free-standing cobalt oxide (Co3O4) nanoneedle arrays on a flexible carbon cloth (CC) substrate and used them as electrode materials with a high catalytic activity for nonenzymatic glucose sensing. Benefiting from the densely arrayed and free-standing Co3O4 nanoneedles with a large surface area, the resulting Co3O4/CC electrode exhibits an excellent sensing performance for glucose with a broad linear range and low detection limit (0.23 μM). More importantly, the Co3O4/CC electrode also exhibited a good performance for determining phosphate ions in a glucose containing alkaline solution. Under optimal condition, the resulted electrode exhibits a linear range of 0.1–1.0 mM and 1.0–30.0 mM with a detection limit of 10 μM for phosphate anion. The as-proposed electrode was further used for the determination of glucose and phosphate ions in human blood serum and urine samples with satisfactory recoveries, verifying the feasibility and great potential as a sensitive, selective, potable, and low-cost electrochemical electrode in sensing application.