Nanomaterials Synthesis

This paper describes the synthesis and biofunctionalization of magnetic nanoparticles (MNPs) of about 10 nm obtained by the coprecipitation method under alkaline conditions. These homemade nanoparticles were conveniently modified with L-lysine and glutaraldehyde and used as solid support for the immunochemical determination of Escherichia coli. Biofunctionalized MNPs were characterized by X-ray diffraction (XRD), Fourier-Transform Infrared spectroscopy (FTIR), Atomic Force Microscopy (AFM), and thermogravimetric analysis. Electrochemical detection was based on a sandwich Enzyme-Linked Immuno Magnetic Electrochemical (ELIME) method using a primary antibody (capture antibody, Ab1) and an HRP-labeled antibody (secondary, Ab-HRP). The enzymatic by-product was measured by constant potential amperometry. In the work described here, a quantitative determination of E. coli was achieved with a linear working range between 266 and 1 × 10 6 CFU mL-1 and a detection limit of ca. 80 CFU/mL. The sensitivity and the crossreactivity of the proposed method against E. coli were tested using other commercial magnetic beads such as epoxy and undecaldehyde-modified MNPs and various potential interferences such as Pseudomonas aeruginosa, Enterococcus faecalis, Salmonella enterica, and Acinetobacter baumannii. The results showed similar analytical properties between the different commercial approaches and the homemade MNPs. This fact makes the MNP-Lys a very promising material for its integration into electrochemical sensing platforms.

Per-and polyfluoroalkyl substances (PFAS) are a large class of synthetic chemicals widely used for their hydrophobic and lipophobic properties in industrial and consumer products. However, their extreme persistence, bioaccumulation, and toxicity have led to significant environmental and human health concerns. Conventional treatment methods are often inadequate for PFAS removal due to the stability of the carbon-fluorine bond. In recent years, innovative approaches have emerged, particularly those employing advanced nanomaterials, electrochemical oxidation, and biological degradation techniques. Nanomaterial-based remediation leverages high surface area and tailored surface functionalities for enhanced adsorption and catalytic breakdown of PFAS. Electrochemical methods offer controllable and energy-efficient degradation pathways, capable of mineralizing PFAS into less harmful by-products. Meanwhile, biological strategies, though still developing, present sustainable and cost-effective prospects through microbial adaptation and enzymatic degradation mechanisms. Despite these advancements, key challenges remain, including incomplete defluorination, by-product formation, scalability, and economic feasibility. Future research should focus on integrating these methods into hybrid systems, optimizing materials design, and understanding degradation mechanisms at the molecular level to achieve effective and sustainable PFAS remediation.

Microstructures of sodium deoxycholate hydrogels were observed to be altered considerably in the presence of variable tris(hydroxymethyl)aminomethane (TRIS) concentrations. These observations were confirmed by use of X-ray diffraction, polarized optical microscopy, rheology, and differential scanning calorimetry measurements. Our studies reveal enhanced gel crystallinity and rigidity with increasing TRIS concentration. The tunable hydrogel microstructures obtained under various conditions have been successfully utilized as templates to synthesize cyanine based fluorescent nanoGUMBOS (nanoparticles from a Group of Uniform Materials Based on Organic Salts). A systematic variation in size (70-200 nm), with relatively low polydispersity and tunable spectral properties of [HMT][AOT] nanoGUMBOS, was achieved by use of these modified hydrogels. The gel microstructures are observed to direct the size, as well as molecular selfassembly of the nanomaterials, thereby tuning their spectral properties. These modified hydrogels were also found to possess other interesting properties such as variable morphologies ranging from fibrous to spherullites, variable degrees of crystallinity, rigidity, optical activity, and release profiles which can be exploited for a multitude of applications. Hence, this study demonstrates a novel method for modification of sodium deoxycholate hydrogels, their applications as templates for nanomaterials synthesis, as well as their potential applications in biotechnology and drug delivery.

The highly porous three-dimensional TiO 2 @Cd-MOF (MOF-Metal-organic framework) nanocomposite aerogels were synthesized through a slightly modified version of the conventional sol-gel method used to synthesize mesoporous TiO 2 aerogels. The as-prepared nanocomposite aerogels were further immersed in solutions of Zn(II) porphyrin (ZnPp) to obtain Zn(II) porphyrin-sensitized nanocomposite aerogel (TiO 2 @Cd-MOF)@ZnPp. The newly synthesized (TiO 2 @Cd-MOF)@ZnPp materials were used as novel heterogeneous photocatalyst and their photocatalytic performances were evaluated by testing the photodegradation of model pollutant methyl orange (MO) dye under visible-light irradiation. The obtained results showed that the heterogeneous photocatalysts exhibited a superior photocatalytic activity compared with pure aerogel and nanocomposite aerogel towards the degradation of pollutants. The maximum degradation efficiency of 94.1% was obtained for heterogeneous photocatalyst. Further, the results of recycle tests confirmed the good photostability of the photocatalyst. The synergistic effects of the heterostructure, an enhanced optical absorption, and efficient electron injection are the prime factors responsible for the photocatalytic activity improvement of (TiO

A novel magnetic-responsive two-layered nanocarrier based on chitosan was developed to enhance therapeutic efficiency and controlled release of Cephalexin. This smart, biocompatible, and biodegradable system utilizes magnetic forces to precisely direct and regulate the release of drugs, ensuring targeted delivery while minimizing systemic side effects. The mesoporous silica interlayer enhances drug loading capacity, mechanical stability, and diffusion-controlled release. At the same time, incorporating dual chitosan layers promotes superior biocompatibility, gradual enzymatic degradation, and pH-responsive behavior. The results demonstrated high drugloading efficiency, pH sensitivity, and a strong response to magnetic stimuli, allowing controlled drug dispersion to specific tissues upon exposure to a magnetic field. In vitro drug release studies confirmed that applying a magnetic field significantly accelerated the release of Cephalexin, particularly at physiological pH levels. Antibacterial assessments revealed enhanced antimicrobial activity of the nanocarrier, with the highest inhibitory effect observed against Bacillus subtilis. Additionally, in vivo cytotoxicity tests on HeLa cancer cells demonstrated a 64 % cell destruction rate at a 50 mg/ml nanocarrier concentration. These findings establish an advanced drug delivery system capable of precisely controlling cephalexin release via magnetic forces, reducing treatment costs, and improving outcomes in bacterial infections and cancer treatments.

Zoonotic diseases, defined as those that are infectious and transmitted from animals to humans, constitute a substantial global health concern. Despite concerted efforts to eradicate or control these diseases, healthcare systems continue to face a substantial burden due to their re-emergence. The early and accurate detection of bacterial pathogens is of crucial importance in order to prevent the potential health consequences associated with zoonotic infections. However, conventional diagnostic methods such as Polymerase Chain Reaction (PCR), culture-based techniques, and immunological assays have limitations, including costliness, labour-intensiveness, and lengthy turnaround times for results. There is an increasing interest in the development of faster, more accurate, and cost-effective diagnostic methods to address these challenges. The utilization of nanobiosensors has emerged as a promising tool for the rapid detection of infectious disease agents. The utilization of biological recognition elements by these devices enables the detection of specific pathogens, with the potential to effect a paradigm shift in diagnostic practices. Furthermore, the incorporation of nanotechnology, particularly nanomaterials, has been demonstrated to enhance the performance of biosensors by improving their specificity and sensitivity. This review explores the application of biosensors and nanobiosensors to rapidly detect Salmonella, Clostridium, Escherichia, and Brucella spp. infections. These innovative technologies offer several advantages over traditional diagnostic methods, including reduced cost, simplified workflows, and faster results. The capacity of nanobiosensors to discern the presence of bacterial pathogens in a variety of sample types, encompassing environmental samples, animal specimens and clinical samples, renders them a versatile instrument for the implementation of disease surveillance and control measures. Furthermore, nanobiosensors have demonstrated considerable potential in enhancing the sensitivity and specificity of detection assays, thereby facilitating the early identification of Salmonella, Clostridium, Escherichia, and Brucella spp., even at low concentrations. By leveraging advancements in nanotechnology, researchers can further improve the performance and reliability of biosensors for zoonotic disease diagnosis. The integration of biosensors and nanotechnology has been demonstrated to hold significant potential for enhancing the detection and characterisation of Salmonella, Clostridium, Escherichia, and Brucella spp. The implementation of these innovative diagnostic tools has the potential to transform disease surveillance efforts, mitigate the spread of zoonotic diseases, and ultimately improve public health outcomes on a global scale.

Despite advances in nanomaterials synthesis, the bottom-up preparation of nanopatterned films as templates for spatially confined surface reactions remains a challenge. We report an approach to fabricating nanoscale thin film surface structures with periodicities on the order of 20 nm and with the capacity to localize reactions with small molecules and nanoparticles. A block copolymer (BCP) of polystyrene-block-poly[(allyl glycidyl ether)-co-(ethylene oxide)] (PS-b-P(AGE-co-EO)) is used to prepare periodically ordered, reactive thin films. As proof-of-principle demonstrations of the versatility of the chemical functionalization, a small organic molecule, an amino acid, and ultrasmall silica nanoparticles are selectively attached via thiol-ene click chemistry to the exposed P(AGE-co-EO) domains of the BCP thin film. Our approach employing click chemistry on the spatially confined reactive surfaces of a BCP thin film overcomes solvent incompatibilities typically encountered when synthetic polymers are functionalized with watersoluble molecules. Moreover, this post-assembly functionalization of a reactive thin film surface preserves the original patterning reduces the amount of required reactant, and leads to short reaction times. The demonstrated approach is expected to provide a new materials platform in applications including sensing, catalysis, pattern recognition, or microelectronics.

The rapid evolution of nanotechnology has catalyzed significant advancements in the design and application of nano-sensors, particularly within the food industry, where ensuring safety and quality is of paramount concern. This review explores the multifaceted role of nano-sensors constructed from diverse nanomaterials in detecting foodborne pathogens and toxins, offering a comprehensive analysis of their operational principles, sensitivity, and specificity. Nano-sensors leverage unique physical and chemical properties at the nanoscale to enhance the detection of microbial contamination, actively contributing to food safety protocols. With applications ranging from real-time monitoring of pathogenic bacteria, such as Escherichia coli and Salmonella, to assessing environmental factors affecting food quality, these innovative devices demonstrate unparalleled advantages over conventional detection methods. Recent research illustrates the integration of nano-sensors with biosensing techniques, enabling multiplex analysis and rapid detection. Furthermore, the review addresses current challenges in the commercialization and regulatory landscape of nano-sensor technology, emphasizing the need for ongoing research to optimize their performance and facilitate widespread adoption in food safety systems. Overall, the incorporation of nano-sensors represents a transformative approach to safeguarding public health by proactively managing food safety risks and enhancing the efficiency of food quality assurance processes.

A In this study, nano-scale zero valent iron (nZVI) was synthesized in the ethanol medium by reduction of ferric iron using sodium borohydride as a reducing agent under atmospheric conditions. The synthesized iron nanoparticles are mainly in zero valent oxidation state and remain without significant oxidation for weeks. A methodical characterization of nZVI was carried out using XRD, SEM, TEM, UV and FTIR studies. The acquired iron nanoparticles consist of a zero valent core embracing a rest oxide shell. The iron nanoparticles diameter was predominantly in the range of 10-100 nm. The laboratory synthesized nZVI particles was examined for methylene blue (MB) removal efficiency from aqueous solution in relation to the contact time, dye concentration and temperature. The increase in the contact time and temperature enhanced the dye decolorization. The degradation decreased from 91.7 to 72.0% on increasing the concentration of dye from 10 to 70 mg/L. These findings elucidated the rapid ...

We demonstrate the potential use of 1,1'-bis-(2-(cyclohexyloxy)-2-oxoethyl)-[4,4'bipyridin]-1,1'-diium bromide (BP) and 1-ethyl-3-methylimidazolium chloride (EMI) ionic liquids (ILs) in in-situ synthesis of gold nanoparticles (Au NPs) without using any external reducing or stabilizing agents. Both ILs produced nearly monodisperse NPs of 4-8 nm which were present in the form of self-assembled states. BP coated NPs formed self-assembled sheets and easily transferred to organic phase by employing water insoluble IL as phase transfer agent. The efficiency of phase transfer process was related to the extent of aggregation as well as functional groups. Both ILs coated NPs were further used to extract the proteins from the complex biological mixtures. EMI coated NPs extracted proteins of large molar masses whereas BP coated NPs were good for the extraction of low molecular masses proteins. This disparity was controlled by the substituted functional groups of ILs. Bulky cyclohexyloxy functional groups of BP did not allow extraction of large molar masses proteins. Such a wide applicability of ILs in nanomaterials synthesis opens several new applications in the field of nanomedicine and nanobiotechnology where ILs coated NPs can be used for diverse protein complexation.

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Background/aim: We aimed to develop a rapid method to enumerate Listeria monocytogenes (L. monocytogenes) utilizing magnetic nanoparticle based preconcentration and surface-enhanced Raman spectroscopy measurements. Materials and methods: Biological activities of magnetic Au-nanoparticles have been observed to have the high biocompatibility, and a sample immunosensor model has been designed to use avidin attached Au-nanoparticles for L. monocytogenes detection. Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium) bacteria cultures were chosen for control studies. Antimicrobial activity studies have been done to identify bio-compatibility and bio-characterization of the Au-nanoparticles in our previous study and capturing efficiencies to bacterial surfaces have been also investigated. Results: We constructed the calibration graphs in various population density of L. monocytogenes as 2.2 × 10 1 to 2.2 × 10 6 cfu/mL and the capture efficiency was found to be 75%. After the optimization procedures, population density of L. monocytogenes and Raman signal intensity showed a good linear correlation (R 2 = 0.991) between 10 2 to 10 6 cfu/mL L. monocytogenes. The presented sandwich assay provides low detection limits and limit of quantification as 12 cfu/mL and 37 cfu/mL, respectively. We also compared the experimental results with reference plate-counting methods and the practical utility of the proposed assay is demonstrated using milk samples. Conclusion: It is focused on the enumeration of L. monocytogenes in milk samples and the comparision of results of milk analysis obtained by the proposed SERS method and by plate counting method stay in food agreement. In the present study, all parameters were optimized to select SERS-based immunoassay method for L. monocytogenes bacteria to ensure LOD, selectivity, precision and repeatablity.

Pathogens cause significant morbidity and mortality to humans. Thus, development of fast and reliable methods for detection and identification of pathogens is urgently needed to increase protection level of public health and ensure the safety of consumers. Herein, a rapid and sensitive method has been developed for Staphylococcus aureus (S. aureus) detection based on the dual role of polydopamine modified magnetic nanoparticles (PDA@ Fe 3 O 4 NPs) combined with polymerase chain reaction (PCR) and capillary electrophoresis (CE). The core-shell type structure PDA@Fe 3 O 4 NPs were prepared, which are spherical, about 152 ± 20 nm in diameter and the PDA shell is about 17.5 ± 1.6 nm. PDA@Fe 3 O 4 NPs play a dual role including efficient capture of bacteria and extraction of DNA. In the pH range of 3.0-7.0, the capture efficiency of S. aureus by PDA@Fe 3 O 4 NPs was more than 95% in 5 min. The adsorption capacity of the PDA@Fe 3 O 4 NPs for S. aureus is 1.2 × 10 8 cfu mg −1. The efficient capture and concentration of bacteria from large volumes of samples by PDA@Fe 3 O 4 NPs avoids the time-consuming culture-enrichment prior to PCR. Interestingly, PDA@Fe 3 O 4 NPs were also found to be efficient adsorbents for extraction of genomic DNA from pathogens based on the electrostatic interaction. The process can be finished in 25 min. The PDA@Fe 3 O 4 NPs based solid phase extraction combined with PCR and CE allows for detecting the order of 10 2 cfu mL −1 S. aureus in tap water and orange juice samples. The whole process takes < 5.5 h. The developed method would provide a promising platform for rapid and sensitive detection of pathogens.

Thousands of foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. Foodborne pathogens can contaminate food items not only during production and processing, but also at the time of storage and transport before consuming. During their growth, these microorganisms are capable of secreting different type of toxins into the extracellular environment. Likewise, other harmful substances can be also released and can contaminate food after breakup of food pathogens. Many microbial toxins can withstand inactivation, and can endure harsh treatment during food processing. Many of these molecules are partaken in cellular processes and can display different mechanisms of pathogenesis of foodborne organisms. Thus studying the properties of foodborne pathogens can help in the understanding of their contamination and inactivation. In the present review, we discussed extensively on the properties of foodborne pathogens including bacteria, vi...

Protease is an enzyme which has a wide range of applications in various fields. Extracellular protease was produced from Pseudomonas aeruginosa and Enterococcus hirae which were isolated from the effluents of diary industries. Protease immobilized with super paramagnetic nanoparticles was characterized by DLS, XRD and TEM methods in relation to their size and structure. The protease enzyme was bound to magnetic nanoparticles via surface transformation technique including Silica coated magnetic Nano composite, amine and cysteine functioned Nano composite formation. Successful binding of protease onto the particles was confirmed by TEM imaging. The maximal enzyme activity of immobilized protease was determined using universal protease assay and was found to be 105µg mL-1 & 290µg mL-1 for Pseudomonas sp. and Enterococcus sp. respectively. The immobilization capacity of protease onto nanoparticles was 6000µM/g. The stability of the immobilized enzyme increased in comparison with the free enzyme. Overall, this study showed that the stability and activity of the protease was enhanced by immobilization to the magnetic nanoparticles. This suggested that immobilized enzyme on the magnetic beads of nanoparticles could be used in an interesting range of applications, both in broader temperature and pH ranges, also permitting magnetic recovery of the enzyme for reuse or purification of the product.

The detection of pathogenic bacteria is essential to prevent and treat infections and to provide food security. Current gold-standard detection techniques, such as culture-based assays and polymerase chain reaction, are time-consuming and require centralized laboratories. Therefore, efforts have focused on developing point-of-care devices that are fast, cheap, portable and do not require specialized training. Paper-based analytical devices meet these criteria and are particularly suitable to deployment in low-resource settings. In this Review, we highlight paperbased analytical devices with substantial point-of-care applicability for bacteria detection and discuss challenges and opportunities for future development. Sections Paper-based sensing platforms An important feature of paper-based sensors is that they can spontaneously transport liquid via capillary flow and, therefore, do not require pumps. In addition, the pore size of paper can easily be tuned to change the flow rate, and paper has a high surface-to-volume ratio, which allows for reagent immobilization and storage. The most popular paper-based platforms are colorimetric-based lateral flow assays (LFAs) (Fig. 2). Generally, LFAs consist of a sample pad, a conjugate pad, a detection pad and an absorbent pad. For a standard immune sandwich assay, the sample is first introduced onto the sample pad to initiate the absorption process. The sample then migrates towards the conjugate pad, where it interacts with labelled detection bioreceptors, usually nanoparticleconjugated antibodies. Upon further migration, the sample reaches the Chembio develops irst POC device for simultaneous detection of treponemal and nontreponemal antibodies in patient samples 179 Printed paper-based sensor for bacterial detection using a luorogenic DNAzyme-based composite ink 120 µPADs for pathogen detection in food samples using enzyme-chromogenic substrate interactions 128 First paper-based airborne bacteria detection using ATP 156

With the advent of microand nanotechnology, major advances and breakthroughs have taken place in many areas, such as biotechnology, medicine, pharmacy or material industry. Gold nanoparticles (AuNPs) with their unique optical and physical properties as well as biocompatibility have already proved themselves to be powerful tool in biological applications. In this work, AuNPs were selected as a potential electrochemically active label. With the aim to use them as an electrochemical active tag, two types of AuNPs were tested and suitable protocols for their functionalization were optimized. Non-functionalized AuNPs were modified with thiolated DNA oligonucleotides using Au-S bond. Such conjugates could be potentionally used as a DNA probe. Functionalized AuNPs containing carboxyl groups were also modified, but with specific antibodies. In this case, the goal was to optimize suitable protocol for effective modification performed with carbodiimide crosslinker enabling direct and covalent...

Objective: The present research is an attempt to optimize the process parameters for phenol removal from aqueous solution using Nano zero-valent iron (NZVI) impregnated cashew nut shell (NZVI-CNS) by adopting statistical tool Response Surface Methodology-Box Behnken Design (RSM-BB). Methods: Box Behnken Design (RSM-BB) design was used to explore the effect of variables on the removal of phenol. In RSM-BB method, high and low values were assigned for the five variables viz. initial pH, NZVI-CNS dosage, initial concentration, contact time and temperature. The preparation was carried out by simple liquid-phase reduction method, namely borohydride reduction method. Results: The results of RSM-BB method showed the significant effect of pH (A), Dose (B), initial concentration (C), time (D), and temperature (E) on phenol removal from aqueous solution. The results of ANOVA and regression of the second order model showed that the linear effects of Dose (B) and Temperature and cross products effects of temperature and pH were more significant. All the critical variables having the greatest effect on the removal of phenol from Nano zero valent iron impregnated cashew nut shell. Conclusion: Nano zero valent iron impregnated cashew nut shell successfully employed to remove phenol from aqueous solution. The factors optimized in the present work would helpful in phenol removal from aqueous solution.

The aim of this work is to evaluate the efficacy of using virtual reality to develop training modules for students who are participating in mechanical engineering laboratory classes. We investigated the feasibility of applying virtual reality and augmented reality technologies in manufacturing and material testing training programs to increase academic achievement, engagement, attitudes and self-efficacy toward engineering and also in fostering more effective use of expensive lab-equipment. We hypothesized that providing students with virtual reality and augmented reality enabled personalized manufacturing labs would increase students’ engagement and learning in this laboratory course. To validate the prototype and test our hypotheses, we conducted pilot testing at Texas A&M University. The total number of students with complete data analyzed for this study was 118. A two-group, randomized control group experiment was conducted. No significant differences were found for pre-existing...

Thousands of foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. Foodborne pathogens can contaminate food items not only during production and processing, but also at the time of storage and transport before consuming. During their growth, these microorganisms are capable of secreting different type of toxins into the extracellular environment. Likewise, other harmful substances can be also released and can contaminate food after breakup of food pathogens. Many microbial toxins can withstand inactivation, and can endure harsh treatment during food processing. Many of these molecules are partaken in cellular processes and can display different mechanisms of pathogenesis of foodborne organisms. Thus studying the properties of foodborne pathogens can help in the understanding of their contamination and inactivation. In the present review, we discussed extensively on the properties of foodborne pathogens including bacteria, vi...

Thousands of foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. Foodborne pathogens can contaminate food items not only during production and processing, but also at the time of storage and transport before consuming. During their growth, these microorganisms are capable of secreting different type of toxins into the extracellular environment. Likewise, other harmful substances can be also released and can contaminate food after breakup of food pathogens. Many microbial toxins can withstand inactivation, and can endure harsh treatment during food processing. Many of these molecules are partaken in cellular processes and can display different mechanisms of pathogenesis of foodborne organisms. Thus studying the properties of foodborne pathogens can help in the understanding of their contamination and inactivation. In the present review, we discussed extensively on the properties of foodborne pathogens including bacteria, vi...

In this paper we introduce a new concept of a d-bimorphism on a vector lattice and prove that, for vector lattices A and B, the Arens triadjoint T * * * : (A ′) ′ n × (A ′) ′ n → (B ′) ′ n of a d-bimorphism T : A × A → B is a d-bimorphism. This generalizes the concept of d-algebra and some results on the order bidual of d-algebras.

Recent years have witnessed the emergence of several viruses and other pathogens. Some of these infectious diseases have spread globally, resulting in pandemics. Although biosensors of various types have been utilized for virus detection, their limited sensitivity remains an issue. Therefore, the development of better diagnostic tools that facilitate the more efficient detection of viruses and other pathogens has become important. Nanotechnology has been recognized as a powerful tool for the detection of viruses, and it is expected to change the landscape of virus detection and analysis. Recently, nanomaterials have gained enormous attention for their value in improving biosensor performance owing to their high surface-to-volume ratio and quantum size effects. This article reviews the impact of nanotechnology on the design, development, and performance of sensors for the detection of viruses. Special attention has been paid to nanoscale materials, various types of nanobiosensors, the internet of medical things, and artificial intelligence-based viral diagnostic techniques.

Foodborne illnesses are a public health concern in the United States and worldwide. Recent outbreaks of Escherichia coli O157:H7 have brought to light the need for improved ways to detect foodborne pathogens and minimize serious outbreaks. Unfortunately, current methods for the detection of foodborne pathogens are time intensive and complex. In this study, we designed a spot immunoassay that uses a UCON-potassium phosphate salt aqueous two-phase system (ATPS) for the preconcentration of O157:H7. This platform was tested with samples of O157:H7 spiked in phosphate-buffered saline and milk. The ATPS was found to improve the detection limit of the spot test, yielding detection at 106 cfu/mL within 30 min. This is the first known application of ATPSs to spot immunoassays. Moreover, detection was successfully achieved without upstream processing or dilution of the sample prior to testing, thereby further simplifying the detection process. This technology’s ease of use, sensitivity, and s...

The genus Yersinia contains three well-recognized human pathogens, including Y. enterocolitica, Y. pestis, and Y. pseudotuberculosis. Various domesticated and wild animals carry Yersinia in their intestines. Spread to individuals arises from eating food or water contaminated by infected human or animal faeces. Interaction with infected pets and domestic stock may also lead to infection. Yersinia is able to multiply at temperatures found in normal refrigerators; hence, a large number of the bacteria may be present if meat is kept without freezing. Yersinia is also rarely transmitted by blood transfusion, because it is able to multiply in stored blood products. Infection with Yersinia can cause yersiniosis, a serious bacterial infection associated with fever, abdominal pain and cramps, diarrhea, joint pain, and symptoms similar to appendicitis in older children and adults. This paper describes a novel immunosensor approach using graphene quantum dots (GQDs) as enzyme mimics in an elec...

The presence of pork content in food products can be a serious issue over an adulteration of food, particularly for consumers who pay attention to halal certification or other religious beliefs concerning the consumption of pork. Due to this fact, finding a method for the detection of pork content in food products that is sensitive, fast, and accurate is of interest. In this study, an electrochemical DNA biosensor with gold nanoparticle-DNA probe bioconjugates was developed to detect Sus scrofa mitochondrial DNA (mtDNA) using a gold-modified screen-printed carbon electrode (SPCE-Gold). The bioconjugates were formed by attaching the DNA probe with gold nanoparticles (AuNPs). Detection was carried out based on the optimum conditions resulting from the Box-Behnken experimental design that were 40 μL of 153 μg/mL bioconjugates; bioconjugate immobilization time, 20 min; and DNA hybridization time, 60 min. The hybridization of target synthetic DNA to the DNA probe was characterized by voltammetry based on the methylene blue indicator signal at a potential of about − 0.35 V. The results showed that the detection limit was 0.58 μg/mL and the recovery was 101.74%. mtDNA samples from various raw and processed meat were isolated and cut with restriction enzyme Sal1. Hybridization of mtDNA samples to the gold nanoparticle-DNA probe bioconjugates anchored to the SPCE-Gold surface was characterized based on the current response generated by methylene blue as an indicator. The result shows that there is an increasing trend in the response of raw and processed meat samples containing pork DNA. The development of an electrochemical DNA biosensor, based on gold nanoparticle-DNA probe bioconjugates, has not been reported previously. This biosensor is selective towards 10% of the pork DNA content in the mixture. Therefore, this biosensor method can be used as an alternative method to distinguish samples containing pork, according to the detection limit.

Microorganisms have a significant influence on human activities and health, and consequently, there is high demand to develop automated, sensitive, and rapid methods for their detection. These methods might be applicable for clinical, industrial, and environmental applications. Although different techniques have been suggested and employed for the detection of microorganisms, and the majority of these methods are not cost effective and suffer from low sensitivity and low specificity, especially in mixed samples. This paper presents a comprehensive review of microbiological techniques and associated challenges for bioengineering researchers with an engineering background. Also, this paper reports on recent technological advances and their future prospects for a variety of microbiological applications.

Advanced nanomaterials indubitably represent one of the most propitious class of new materials due to their intriguing optical, electronic and redox properties. The incredible progress achieved in this research area has been propelled by the development of novel synthetic procedures owing to the emergence of nanotechnology and by the wide range of applications. These nanostructured materials possess high surface area, biocompatibility, nontoxicity and charge-sensitive conductance which have led to the development of simple, rapid, highly sensitive, inexpensive and portable electrochemical genosensors. This review accentuates on the development and validation of various advanced nanomaterials based electrochemical genosensors that utilize unique properties of nanomaterials for signal transduction purpose or as an electroactive species for direct detection of analyte. The intent is to highlight the recent progress on highly sensitive and flexible nanostructured material based electrochemical genosensors that have the potential to be developed as the next generation field-deployable analytical tools.

Advanced nanomaterials indubitably represent one of the most propitious class of new materials due to their intriguing optical, electronic and redox properties. The incredible progress achieved in this research area has been propelled by the development of novel synthetic procedures owing to the emergence of nanotechnology and by the wide range of applications. These nanostructured materials possess high surface area, biocompatibility, nontoxicity and charge-sensitive conductance which have led to the development of simple, rapid, highly sensitive, inexpensive and portable electrochemical genosensors. This review accentuates on the development and validation of various advanced nanomaterials based electrochemical genosensors that utilize unique properties of nanomaterials for signal transduction purpose or as an electroactive species for direct detection of analyte. The intent is to highlight the recent progress on highly sensitive and flexible nanostructured material based electroc...

Bacteria-related pathogenic diseases are one of the major health problems throughout the world. Salmonella is a genus of rod-shaped Gram-negative enterobacteria of which more than 2600 serotypes have been identified. Infection with Salmonella can cause salmonellosis, a serious bacterial toxi-infection syndrome associated with gastroenteritis, and paralyphoid and typhoid fevers. Its rapid and sensitive detection is a key to the prevention of problems related to health. This paper describes the development of antibody and DNA sensors for Salmonella detection using a microfluidic-based electrochemical system. Commercial Salmonella typhimurium and Salmonella typhimurium from human stool samples were investigated using standard and nanomaterial-amplified antibody sensors. S. typhimurium could be detected down to 1 cfu mL −1. The specificity of immunoassay was tested by studying with non-specific bacteria including E. coli and S. aureus that revealed only 2.01% and 2.66% binding when compared to the target bacterium. On the other hand, the quantification of Salmonella DNA was investigated in a concentration range of 0.002-200 µM using the developed DNA biosensor that demonstrated very high specificity and sensitivity with a detection limit of 0.94 nM. Our custom-designed microfluidic sensor offers rapid, highly sensitive, and specific diagnostic assay approaches for pathogen detection.

Foodborne diseases are critical and become a greater problem over a while. World Health Organization shows that every year 420 000 die from eating contaminated food. Foodborne diseases are any illness resulting from pathogenic bacteria, viruses, and contaminated food. It is important to analyze the food and detect foodborne Bacteria to prevent or minimize diseases and ensure food safety. The designed system aims to detect the foodborne bacteria present in fruits using rapid detection technique instead of traditional methods. Many areas will be impacted by this early detection, for example, the economy, health, and agriculture societies. The system is divided into 3 main parts. First, Extracting DNA from food sample. Then sensing and signal manipulation part and finally signal analysis and bacteria detection. Electrochemical biosensors used for bacteria examination. 27 samples including tomato and apple samples were tested. The results show that each test takes from 12 to 500 seconds not including DNA extraction period with accurate results and cost-friendly.

In the dairy industry, the spreading of phages of Lactococcus lactis (LL) prevents the proper lactic fermentation, causing waste of contaminated products and economic losses. This work presents a cheap biosensing method for rapidly detecting the LL phages. The detection is based on live LL bacteria covering the sensor electrodes, whose electrical response is measured by electrochemical impedance spectroscopy (EIS). Solutions contaminated by phages induce bacteria lysis, clearly reducing the bacteria coverage over the electrodes and leading to evident parametrical shifts in the charge transfer resistance and in the impedance phase at 400 Hz. Experimental tests with laboratory contaminated samples confirm the better detection capability of screen-printed gold sensors compared to the interdigitated gold electrodes. Two measurement protocols, called spill-out and drop-in methods, are evaluated to optimize the sensor detection capability and time. The EIS results are compared with optical absorbance measurements at 600 nm, in order to validate the proposed detection method with 10 7-PFU/mL phages and with a detection time of about 5 h. Finally, the proposed method is tested successfully with milk-based solutions. Evident shifts between phagecontaminated and non-contaminated sensors are measured in the charge transfer resistance of more than one order of magnitude with impedance phase differences of 43 • .

Escherichia coli (E. coli) O157:H7 is a pathogenic bacterium that causes serious toxic effects in the human gastrointestinal tract. In this paper, a method for its effective analytical control in a milk sample was developed. To perform rapid (1 h) and accurate analysis, monodisperse Fe3O4@Au magnetic nanoparticles were synthesized and used in an electrochemical sandwich-type magnetic immunoassay. Screen-printed carbon electrodes (SPCE) were used as transducers, and electrochemical detection was performed by chronoamperometry using a secondary horseradish peroxidase-labeled antibody and 3,3′,5,5′-tetramethylbenzidine. This magnetic assay was used to determine the E. coli O157:H7 strain in the linear range from 20 to 2 × 106 CFU/mL, with a limit of detection of 20 CFU/mL. The selectivity of the assay was tested using Listeria monocytogenes p60 protein, and the applicability of the assay was assessed by analyzing a commercial milk sample, demonstrating the usefulness of the synthesized...

Escherichia coli (E. coli) O157:H7 is a pathogenic bacterium that causes serious toxic effects in the human gastrointestinal tract. In this paper, a method for its effective analytical control in a milk sample was developed. To perform rapid (1 h) and accurate analysis, monodisperse Fe3O4@Au magnetic nanoparticles were synthesized and used in an electrochemical sandwich-type magnetic immunoassay. Screen-printed carbon electrodes (SPCE) were used as transducers, and electrochemical detection was performed by chronoamperometry using a secondary horseradish peroxidase-labeled antibody and 3,3′,5,5′-tetramethylbenzidine. This magnetic assay was used to determine the E. coli O157:H7 strain in the linear range from 20 to 2 × 106 CFU/mL, with a limit of detection of 20 CFU/mL. The selectivity of the assay was tested using Listeria monocytogenes p60 protein, and the applicability of the assay was assessed by analyzing a commercial milk sample, demonstrating the usefulness of the synthesized...

In the dairy industry, the spreading of phages of Lactococcus lactis (LL) prevents the proper lactic fermentation, causing waste of contaminated products and economic losses. This work presents a cheap biosensing method for rapidly detecting the LL phages. The detection is based on live LL bacteria covering the sensor electrodes, whose electrical response is measured by electrochemical impedance spectroscopy (EIS). Solutions contaminated by phages induce bacteria lysis, clearly reducing the bacteria coverage over the electrodes and leading to evident parametrical shifts in the charge transfer resistance and in the impedance phase at 400 Hz. Experimental tests with laboratory contaminated samples confirm the better detection capability of screen-printed gold sensors compared to the interdigitated gold electrodes. Two measurement protocols, called spill-out and drop-in methods, are evaluated to optimize the sensor detection capability and time. The EIS results are compared with optical absorbance measurements at 600 nm, in order to validate the proposed detection method with 10 7-PFU/mL phages and with a detection time of about 5 h. Finally, the proposed method is tested successfully with milk-based solutions. Evident shifts between phagecontaminated and non-contaminated sensors are measured in the charge transfer resistance of more than one order of magnitude with impedance phase differences of 43 • .

Food safety issues are directly related to people’s quality of life, so there is a need to develop efficient and reliable food contaminants’ detection devices to ensure the safety and quality of food. Electrochemical biosensors have the significant advantages of miniaturization, low cost, high sensitivity, high selectivity, rapid detection, and low detection limits using small amounts of samples, which are expected to enable on-site analysis of food products. In this paper, the latest electrochemical biosensors for the detection of biological contaminants, chemical contaminants, and genetically modified crops are reviewed based on the analytes of interest, electrode materials and modification methods, electrochemical methods, and detection limits. This review shows that electrochemical biosensors are poised to provide miniaturized, specific, selective, fast detection, and high-sensitivity sensor platforms for food safety.

Polymeric ion selective electrodes are highly sensitive to changes in zero current ion flow and this offers a route to signal amplification in label-free potentiometric immunosensors. In this work, a label-free potentiometric immunosensor toward Salmonella typhimurium (ST) assembled in a home-made pipette-tip electrode is described. The signal-output amplification was implemented on a gold nanoparticle polymer inclusion membrane (AuNPs-PIM) which was used as sensing platform and for antibody immobilization. Additionally, a marker ion was used to detect the antibody-antigen binding event at the electrode surface. The immunosensor construction was performed in several steps: i) gold salt ions extraction in PVC membrane; ii) AuNPs formation using Na 2 EDTA as reduction agent; iii) antibody anti-Salmonella conjugation on AuNPs-PIM in pipette-tip electrodes. The potential shift observed in potentiometric measurements was derived simply from the blocking effect in the ionic flux caused by antigen-antibody conjugation, without no extra steps, mimetizing the ion-channel sensors. A detection limit of 6 cells mL −1 was attained. As proof-of-concept, recovery studies were performed in spiked commercial apple juice samples with success. Due to the simplicity of use, the appealing cost of equipment and sensor production and being able to provide a quick analytical response (less than 1 h for a complete assay, including sample preparation for analysis), this scheme represents a good prototype device for the detection of foodborne pathogens like ST or other immune-responsive bacteria.

The development of microfluidic systems has made available new high-throughput methods with features essential to miniaturization, such as low consumption of sample and reagents, easy manipulation and reduction in analysis time. However, in addition to these advantages, miniaturized methods are frequently limited by low levels of the two desirable basic properties of sensitivity and selectivity. The use of nanomaterials (NMs) in microfluidic methods is a recent trend, mainly using their special physical and chemical features to improve sensitivity and selectivity. This review reports on a systematic study of the usefulness of NMs in the different steps of the analytical process for microfluidic systems: preconcentration, separation, reaction and detection. We illustrate the advantages offered by NMs in each of these steps with representative recent examples that highlight the scientific interest in widening the use of nanotechnology in microfluidic methods. Also, we briefly discuss the use of NMs in paper-microfluidic methods.

In the Present work, pure and Ce doped SnO2 nanoparticles have been prepared by the Co-precipitation method. The prepared samples have investigated by Powder XRD pattern, FT-IR, SEM and EDAX analysis, UV-Vis measured. From the XRD pattern of all the prepared samples are identified as Orthorhombic with space group pnnm (58) and the grain size in the range of 24.85nm. In FT-IR results indicates the information of the O-Sn-O bonds shows that the stretching of vibration bonds in the particular frequency region. From the UV-Vis absorption spectra, to find the band gap energy of the prepared tin oxide nanoparticles by using Tauc&#39;s plot. SEM and EDAX for various concentration were confirms the surface morphology of SnO2 nanoparticles.