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At present, both native and immobilized nanoparticles are of great importance in many areas of science and technology. In this paper, we have studied magnetic iron oxide nanoparticles and their aggregates bound on woven cotton textiles employing two simple modification procedures. One modification was based on the treatment of textiles with perchloric-acid-stabilized magnetic fluid diluted with methanol followed by drying. The second procedure was based on the microwave-assisted conversion of ferrous sulfate at high pH followed by drying. The structure and functional properties of these modified textiles were analyzed in detail. Scanning electron microscopy of native and modified textiles clearly showed the presence of iron oxide nanoparticles on the surface of the modified cotton fibers. All of the modified textile materials exhibited light to dark brown color depending on the amount of the bound iron oxide particles. Magnetic measurements showed that the saturation magnetization values reflect the amount of magnetic nanoparticles present in the modified textiles. Small-angle X-ray and neutron scattering measurements were conducted for the detailed structural characterization at the nanoscale of both the native and magnetically modified textiles, and different structural organization of nanoparticles in the two kinds of textile samples were concluded. The textile-bound iron oxide particles exhibited peroxidase-like activity when the N , N -diethyl- p -phenylenediamine sulfate salt was used as a substrate; this nanozyme activity enabled rapid decolorization of crystal violet in the presence of hydrogen peroxide. The deposition of a sufficient amount of iron oxide particles on textiles enabled their simple magnetic separation from large volumes of solutions; if necessary, the magnetic response of the modified textiles can be simply increased by incorporation of a piece of magnetic iron wire. The simplicity of the immobilized nanozyme preparation and the low cost of all the precursors enable its widespread application, such as decolorization and degradation of selected organic dyes and other important pollutants. Other types of textile-bound nanozymes can be prepared and used as low-cost catalysts for a variety of applications.

The determination of contaminants of emerging concern (CECs) in environmental samples has become a challenging and critical issue. The present work focuses on miniaturized analytical strategies reported in the literature for the determination of CECs. The first part of the review provides brief overview of CECs whose monitoring in environmental samples is of particular significance, namely personal care products, pharmaceuticals, endocrine disruptors, UV-filters, newly registered pesticides, illicit drugs, disinfection by-products, surfactants, high technology rare earth elements, and engineered nanomaterials. Besides, an overview of downsized sample preparation approaches reported in the literature for the determination of CECs in environmental samples is provided. Particularly, analytical methodologies involving microextraction approaches used for the enrichment of CECs are discussed. Both solid phase- and liquid phase-based microextraction techniques are highlighted devoting special attention to recently reported approaches. Special emphasis is placed on newly developed materials used for extraction purposes in microextraction techniques. In addition, recent contributions involving miniaturized analytical flow techniques for the determination of CECs are discussed. Besides, the strengths, weaknesses, opportunities and threats of point of need and portable devices have been identified and critically compared with chromatographic methods coupled to mass chromatography. Finally, challenging aspects regarding miniaturized analytical methods for determination of CECs are critically discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Novel modern easily feasible methods for direct evaluation of a new, simple preconcentration analytical procedure have been developed. Two types of smartphone image analysis applications (ON Color Measure and Color Lab) were evaluated to obtain RGB and HSV color spaces data for the quantification of Magnetic textile solid phase extraction of colored compounds (e.g. water-soluble organic dyes). Both direct measurement of color spaces values via the smartphone camera and image analysis of the photograph can be used successfully. The obtained data were similar to those obtained by previously examined professional ImageJ software. The saturation (S) values of the HSV color space are directly proportional to the concentrations of the analyzed dye., (© 2019 Published by Elsevier Ltd.)

Magnetic textile solid phase extraction, based on the use of magnetically modified non-woven textile impregnated with chitosan, was successfully employed for the preconcentration of acid food dyes from water solutions. The photos of textile squares with the adsorbed dye were taken with a mobile phone. The image analysis of the photos was performed using appropriate freeware. The values of saturation, obtained through the HSB color space, were proportional to the dye concentration in the analyzed samples. Described inexpensive, simple and elution free assay enables analysis of dyes concentration in various solutions. This novel method has a potential to be a useful alternative to existing semiquantitative determination procedures, especially for dyes analysis., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Physiological aggregation of a recombinant enzyme into enzymatically active inclusion bodies could be an excellent strategy to obtain immobilized enzymes for industrial biotransformation processes. However, it is not convenient to recycle "gelatinous masses" of protein inclusion bodies from one reaction cycle to another, as high centrifugation forces are needed in large volumes. The magnetization of inclusion bodies is a smart solution for large-scale applications, enabling an easier separation process using a magnetic field., Results: Magnetically modified inclusion bodies of UDP-glucose pyrophosphorylase were recycled 50 times, in comparison, inclusion bodies of the same enzyme were inactivated during ten reaction cycles if they were recycled by centrifugation. Inclusion bodies of sialic acid aldolase also showed good performance and operational stability after the magnetization procedure., Conclusions: It is demonstrated here that inclusion bodies can be easily magnetically modified by magnetic iron oxide particles prepared by microwave-assisted synthesis from ferrous sulphate. The magnetic particles stabilize the repetitive use of the inclusion bodies .

The annual food and agricultural waste production reaches enormous numbers. Therefore, an increasing need to valorize produced wastes arises. Waste materials originating from the food and agricultural industry can be considered as functional materials with interesting properties and broad application potential. Moreover, using an appropriate magnetic modification, smart materials exhibiting a rapid response to an external magnetic field can be obtained. Such materials can be easily and selectively separated from desired environments. Magnetically responsive waste derivatives of biological origins have already been prepared and used as efficient biosorbents for the isolation and removal of both biologically active compounds and organic and inorganic pollutants and radionuclides, as biocompatible carriers for the immobilization of diverse types of (bio)molecules, cells, nano- and microparticles, or (bio)catalysts. Potential bactericidal, algicidal, or anti-biofilm properties of magnetic waste composites have also been tested. Furthermore, low cost and availability of waste biomaterials in larger amounts predetermine their utilization in large-scale processes.

Bacterial cellulose (BC) produced by Komagataeibacter sucrofermentans was magnetically modified using perchloric acid stabilized magnetic fluid. Magnetic bacterial cellulose (MBC) was used as a carrier for the immobilization of affinity ligands, enzymes and cells. MBC with immobilized reactive copper phthalocyanine dye was an efficient adsorbent for crystal violet removal; the maximum adsorption capacity was 388mg/g. Kinetic and thermodynamic parameters were also determined. Model biocatalysts, namely bovine pancreas trypsin and Saccharomyces cerevisiae cells were immobilized on MBC using several strategies including adsorption with subsequent cross-linking with glutaraldehyde and covalent binding on previously activated MBC using sodium periodate or 1,4-butanediol diglycidyl ether. Immobilized yeast cells retained approximately 90% of their initial activity after 6 repeated cycles of sucrose solution hydrolysis. Trypsin covalently bound after MBC periodate activation was very stable during operational stability testing; it could be repeatedly used for ten cycles of low molecular weight substrate hydrolysis without loss of its initial activity., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Smart materials of biological origin are attracting a lot of attention nowadays, especially as catalysts, carriers or adsorbents. Among them, magnetically modified biomaterials are especially important due to their response to external magnetic field. This report demonstrates that naturally occurring micrometer sized, high aspect ratio material (native and autoclaved Leptothrix sp. sheaths) efficiently bind synthetically prepared magnetite and maghemite nanoparticles and their aggregates. Magnetic modification of Leptothrix sheaths enables to prepare a promising material for advanced biotechnology and environmental technology applications. The prepared magnetically responsive sheaths were tested as inexpensive adsorbent for crystal violet removal from aqueous solutions. The observed maximum adsorption capacity was 243.1mg of dye per 1g of adsorbent., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The majority of algal cells can interact with a wide range of nano- and microparticles. Upon interaction the modified cells usually maintain their viability and the presence of foreign material on their surfaces or in protoplasm can provide additional functionalities. Magnetic modification and labeling of microalgal biomass ensures a wide spectrum of biotechnological, bioanalytical and environmental applications. Different aspects of microalgal cell magnetic modification are covered in the review, followed by successful applications of magnetic algae. Modified cells can be employed during their harvesting and removal, applied in toxicity microscreening devices and also as efficient adsorbents of different types of xenobiotics.

A simple procedure for the synthesis of magnetic fluid (ferrofluid) stabilized by poly(methacrylic acid) has been developed. This ferrofluid was used to prepare a novel type of magnetically responsive chitosan-based composite material. Both ferrofluid and magnetic chitosan composite were characterized by a combination of microscopy (optical microscopy, TEM, SEM), scattering (static and dynamic light scattering, SANS) and spectroscopy (FTIR) techniques. Magnetic chitosan was found to be a perspective material for various bioapplications, especially as a magnetic carrier for immobilization of enzymes and cells. Lipase from Candida rugosa was covalently attached after cross-linking and activation of chitosan using glutaraldehyde. Baker's yeast cells (Saccharomyces cerevisiae) were incorporated into the chitosan composite during its preparation; both biocatalysts were active after reaction with appropriate substrates., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: Barley straw, an agricultural by-product, can also serve as a low-cost and relatively efficient adsorbent of various harmful compounds. In this case, adsorption of four water-soluble dyes belonging to different dye classes (specifically Bismarck brown Y, representing the azo group; methylene blue, quinone-imine group; safranin O, safranin group; and crystal violet, triphenylmethane group) on native and citric acid-NaOH-modified barley straw, both in magnetic and non-magnetic versions, was studied., Results: The adsorption was characterized using three adsorption models, namely Langmuir, Freundlich and Sips. To compare the maximum adsorption capacities (qmax), the Langmuir model was employed. The qmax values reached 86.5-124.3 mg of dye per g of native non-magnetic straw and 410.8-520.3 mg of dye per g of magnetic chemically modified straw. Performed characterization studies suggested that the substantial increase in qmax values after chemical modification could be caused by rougher surface of adsorbent (observed by scanning electron microscopy) and by the presence of higher amounts of carboxyl groups (detected by Fourier transform infrared spectroscopy). The adsorption processes followed the pseudo-second-order kinetic model and thermodynamic studies indicated spontaneous and endothermic adsorption., Conclusion: The chemical modification of barley straw led to a significant increase in maximum adsorption capacities for all tested dyes, while magnetic modification substantially facilitated the manipulation with adsorbent., (© 2015 Society of Chemical Industry.)

The formation of bacterial biofilm on various surfaces has significant negative economic effects. The aim of this study was to find a simple procedure to decrease the Pseudomonas aeruginosa biofilm formation in a water environment by using different food waste biological materials as signal molecule adsorbents. The selected biomaterials did not reduce the cell growth but affected biofilm formation. Promising biomaterials were magnetically modified in order to simplify manipulation and facilitate their magnetic separation. The best biocomposite, magnetically modified spent grain, exhibited substantial adsorption of signal molecules and decreased the biofilm formation. These results suggest that selected food waste materials and their magnetically responsive derivatives could be applied to solve biofilm problems in water environment.

This paper deals with the purification of a class III endochitinase from Euphorbia characias latex. Described purification method includes an effective novel separation step using magnetic chitin particles. Application of magnetic affinity adsorbent noticeably simplifies and shortens the purification procedure. This step and the subsequently DEAE-cellulose chromatography enable to obtain the chitinase in homogeneous form. One protein band is present on PAGE in non-denaturing conditions and SDS-PAGE profile reveals a unique protein band of 36.5 ± 2 kDa. The optimal chitinase activity is observed at 50 °C, pH 5.0. E. characias latex chitinase is able to hydrolyze colloidal chitin giving, as reaction products, N-acetyl-D-glucosamine, chitobiose and chitotriose. Moreover, we observed that calcium and magnesium ions enhance chitinase activity. Finally, we cloned the cDNA encoding the E. characias latex chitinase. The partial cDNA nucleotide sequence contains 762 bp, and the deduced amino acid sequence (254 amino acids) is homologous to the sequence of several plant class III endochitinases., (Copyright © 2015 Elsevier Inc. All rights reserved.)

An extremely simple procedure has been developed for the immobilization of Saccharomyces cerevisiae cells on magnetic chitosan microparticles. The magnetic carrier was prepared using an inexpensive, simple, rapid, one-pot process, based on the microwave irradiation of chitosan and ferrous sulphate at high pH. Immobilized yeast cells have been used for sucrose hydrolysis, hydrogen peroxide decomposition and the adsorption of selected dyes., (Copyright © 2014 John Wiley & Sons, Ltd.)

Magnetically modified yeast cells represent an interesting type of biocomposite material, applicable in various areas of bioanalysis, biotechnology and environmental technology. In this review, typical examples of magnetic modifications of yeast cells of the genera Saccharomyces, Kluyveromyces, Rhodotorula and Yarrowia are presented, as well as their possible applications as biocatalysts, active part of biosensors and biosorbents for the separation of organic xenobiotics, heavy metal ions and radionuclides., (Copyright © 2014 John Wiley & Sons, Ltd.)

Extremely simple procedures for the preparation of magnetic chitosan enzyme carriers have been developed and used for the immobilization of lipase and β-galactosidase as model enzymes. In the first case commercially available magnetite microparticles were entrapped in chitosan gel, while in the second case magnetic iron oxides microparticles were synthesized in chitosan matrix from ferrous sulfate using microwave irradiation. Immobilized enzymes showed long-term stability without leaching of enzyme from the support and enabled their repeated use without significant loss of activity., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Food and feed technology and biotechnology benefit from the use of immobilised enzymes. New low-cost enzyme carriers exhibiting high biocompatibility and response to external magnetic field can substantially improve the application potential of immobilised enzyme systems., Results: Ferrofluid-modified spent grain was used as a low-cost, biocompatible and magnetically responsive carrier for the immobilisation of Candida rugosa lipase. Several immobilisation procedures were tested using both native and poly(ethyleneimine)-modified magnetic spent grain. Activity of immobilised lipase per unit mass of carrier, operational stability, time stability and Michaelis constant were compared. In general, magnetic spent grain modified with poly(ethyleneimine) bound a smaller amount of active lipase than unmodified magnetic spent grain, but the operational and storage stabilities of enzyme immobilised on poly(ethyleneimine)-modified carrier were very high., Conclusion: Ferrofluid-modified spent grain can be a promising low-cost magnetic carrier for enzyme immobilisation, applicable e.g. in food and feed technology and biotechnology., (© 2012 Society of Chemical Industry.)

Magnetic techniques based on the application of magnetic nanoparticles and microparticles and films have been successfully used for the determination and detection of different types of xenobiotics (e.g. herbicides, insecticides, fungicides, aromatic and polyaromatic hydrocarbons, pentachlorophenol and heavy metal ions) as well as viruses, microbial pathogens and protozoan parasites in water samples. Preconcentration of xenobiotics from large volumes of samples can be performed using magnetic solid-phase extraction, stir-bar sorptive extraction and related procedures. This review provides basic information about these techniques. Published examples of successful applications document the importance of these simple and efficient procedures employing magnetic materials.