Application of Iron Nanoparticle-Based Materials in the Food Industry

Due to their different properties compared to other materials, nanoparticles of iron and iron oxides are increasingly used in the food industry. Food technologists have especially paid attention to their ease of separation by magnetic fields and biocompatibility. Unfortunately, the consumption of increasing amounts of nanoparticles has raised concerns about their biotoxicity. Hence, knowledge about the applicability of iron nanoparticle-based materials in the food industry is needed not only among scientists, but also among all individuals who are involved in food production. The first part of this article describes typical methods of obtaining iron nanoparticles using chemical synthesis and so-called green chemistry. The second part of this article describes the use of iron nanoparticles and iron nanoparticle-based materials for active packaging, including the ability to eliminate oxygen and antimicrobial activity. Then, the possibilities of using the magnetic properties of iron nano-oxides for enzyme immobilization, food analysis, protein purification and mycotoxin and histamine removal from food are described. Other described applications of materials based on iron nanoparticles are the production of artificial enzymes, process control, food fortification and preserving food in a supercooled state. The third part of the article analyzes the biocompatibility of iron nanoparticles, their impact on the human body and the safety of their use.

Antimicrobial polysaccharides obtained from natural sources

With the increase in resistance to conventional antibiotics among bacterial pathogens, the search for new antimicrobials becomes more and more necessary. Although most studies focus on the discovery of antimicrobial peptides for the development of new antibiotics, several others in the literature have described polysaccharides with the same biological activity with the potential for use as therapeutic alternatives. Here we review the currently available literature on antimicrobial polysaccharides isolated from different sources to demonstrate that there are several possible unconventional carbohydrate polymers that could act as therapeutic alternatives in the battle against drug-resistant pathogens.

Microbial Fabrication of Nanomaterial and Its Role in Disintegration of Exopolymeric Matrices of Biofilm

Bacterial biofilms are responsible for the development of various chronic wound-related and implant-mediated infections and confer protection to the pathogenic bacteria against antimicrobial drugs and host immune responses. Hence, biofilm-mediated chronic infections have created a tremendous burden upon healthcare systems worldwide. The development of biofilms upon the surface of medical implants has resulted in the failure of various implant-based surgeries and therapies. Although different conventional chemical and physical agents are used as antimicrobials, they fail to kill the sessile forms of bacterial pathogens due to the resistance exerted by the exopolysaccharide (EPS) matrices of the biofilm. One of the major techniques used in addressing such a problem is to directly check the biofilm formation by the use of novel antibiofilm materials, local drug delivery, and device-associated surface modifications, but the success of these techniques is still limited. The immense expansion in the field of nanoscience and nanotechnology has resulted in the development of novel nanomaterials as biocidal agents that can be either easily integrated within biomaterials to prevent the colonization of microbial cells or directly approach the pathogen overcoming the biofilm matrix. The antibiofilm efficacies of these nanomaterials are accomplished by the generation of oxidative stresses and through alterations of the genetic expressions. Microorganism-assisted synthesis of nanomaterials paved the path to success in such therapeutic approaches and is found to be more acceptable for its "greener" approach. Metallic nanoparticles functionalized with microbial enzymes, silver-platinum nanohybrids (AgPtNHs), bacterial nanowires, superparamagnetic iron oxide (Fe₃O₄), and nanoparticles synthesized by both magnetotactic and non-magnetotactic bacteria showed are some of the examples of such agents used to attack the EPS.

Microbial Fabrication of Nanomaterial and Its Role in Disintegration of Exopolymeric Matrices of Biofilm

Bacterial biofilms are responsible for the development of various chronic wound-related and implant-mediated infections and confer protection to the pathogenic bacteria against antimicrobial drugs and host immune responses. Hence, biofilm-mediated chronic infections have created a tremendous burden upon healthcare systems worldwide. The development of biofilms upon the surface of medical implants has resulted in the failure of various implant-based surgeries and therapies. Although different conventional chemical and physical agents are used as antimicrobials, they fail to kill the sessile forms of bacterial pathogens due to the resistance exerted by the exopolysaccharide (EPS) matrices of the biofilm. One of the major techniques used in addressing such a problem is to directly check the biofilm formation by the use of novel antibiofilm materials, local drug delivery, and device-associated surface modifications, but the success of these techniques is still limited. The immense expansion in the field of nanoscience and nanotechnology has resulted in the development of novel nanomaterials as biocidal agents that can be either easily integrated within biomaterials to prevent the colonization of microbial cells or directly approach the pathogen overcoming the biofilm matrix. The antibiofilm efficacies of these nanomaterials are accomplished by the generation of oxidative stresses and through alterations of the genetic expressions. Microorganism-assisted synthesis of nanomaterials paved the path to success in such therapeutic approaches and is found to be more acceptable for its "greener" approach. Metallic nanoparticles functionalized with microbial enzymes, silver-platinum nanohybrids (AgPtNHs), bacterial nanowires, superparamagnetic iron oxide (Fe3O4), and nanoparticles synthesized by both magnetotactic and non-magnetotactic bacteria showed are some of the examples of such agents used to attack the EPS.

Non-toxic nano approach for wastewater treatment using Chlorella vulgaris exopolysaccharides immobilized in iron-magnetic nanoparticles

The current study, novel magnetic nano-composite particles (Fe₃O₄@EPS) were successfully synthesized via the co-precipitation of iron (III) chloride and iron (II) sulfate (Fe₃O₄ nanoparticles) with exopolysaccharides (EPS) derived from the microalga Chlorella vulgaris. The physico-chemical nature of the Fe₃O₄@EPS was investigated in depth. Transmission electron microscopy (TEM) results estimated the core-shell nature of Fe₃O₄@EPS aggregated inside the indistinctly layered EPS matrix to be 10-20 nm in size. Scanning electron microscopy-based energy dispersive spectral analysis indicated that elemental Fe was successfully loaded on to the EPS polymeric ion-exchanger at a rate of 63.3% by weight. FT-IR results demonstrated that Fe₃O₄ nanoparticles were successfully modified by the functional groups present in EPS. Fe₃O₄@EPS showed a highly magnetic nature at 5.0 emu/g. The XPS survey spectrum, which showed two major peaks at 724.1 and 710.2 eV revealed the elemental composition and electronic structure of Fe₃O₄ nanoparticles and Fe₃O₄@EPS. Furthermore, nutrient removal from wastewater was studied. Under optimum conditions (3.5 g/L of Fe₃O₄@EPS, pH 7.0 and 13 h of incubation) 91% of PO₄^3- and 85% of NH₄⁺were effectively eliminated. These findings demonstrate the potential of Fe₃O₄@EPS for removing PO₄^3- and NH₄⁺ in wastewater treatment plants.

Removal of Cr(VI) by magnetic iron oxide nanoparticles synthesized from extracellular polymeric substances of chromium resistant acid-tolerant bacterium Lysinibacillus sphaericus RTA-01

BACKGROUND

Extracellular polymeric substances (EPS) from Cr(VI) resistant acid-tolerant biofilm forming bacterium (CrRAtBb) Lysinibacillus sphaericus RTA-01 was used for synthesis of magnetic iron oxide nanoparticles (MIONPs) in removal of Cr(VI).

METHODS

MIONPs synthesized in EPS matrix were characterized by UV-Vis, DLS, ATR-FTIR, XRD, FESEM, HRTEM and VSM. Primarily, the synthesis of MIONPs was established by the formation of black-colored precipitate through surface plasmon resonance (SPR) peak in between 330 and 450 nm.

RESULTS

The size of the spherical MIONPs with diameter range 13.75-106 nm was confirmed by DLS, XRD and FESEM analysis. HRTEM study confirmed the size of the MIONPs in the range of 10-65 nm. Moreover, the EDX and SAED confirmed the purity and polycrystalline nature of MIONPs. The ATR-FTIR peaks below 1000 cm-1 designated the synthesis of MIONPs. Also, the magnetic property of MIONPs was confirmed for separation from the aqueous solution. MIONPs were further checked for the adsorption of Cr(VI) with initial concentration range of 50-200 mg L-1. An adsorption isotherm and thermodynamic study were also carried out and the experimental data was best fitted in Langmuir isotherm model with maximum adsorption percent of 1052.63 mg g-1 of Cr(VI). Post interaction with Cr(VI), the surface characteristic of MIONPs in EPS matrix was evaluated by zeta potential, EDX, ATR-FTIR and XRD.

CONCLUSION

This study ascertained the adsorption of Cr(VI) over EPS stabilized MIONPs whereas the zeta potential and XRD analysis confirmed the presence of reduced Cr(IV) on the adsorbent surface.

Bacterial Exopolysaccharides as Reducing and/or Stabilizing Agents during Synthesis of Metal Nanoparticles with Biomedical Applications

Bacterial exopolysaccharides (EPSs) are biomolecules secreted in the extracellular space and have diverse biological functionalities, such as environmental protection, surface adherence, and cellular interactions. EPSs have been found to be biocompatible and eco-friendly, therefore making them suitable for applications in many areas of study and various industrial products. Recently, synthesis and stabilization of metal nanoparticles have been of interest because their usefulness for many biomedical applications, such as antimicrobials, anticancer drugs, antioxidants, drug delivery systems, chemical sensors, contrast agents, and as catalysts. In this context, bacterial EPSs have been explored as agents to aid in a greener production of a myriad of metal nanoparticles, since they have the ability to reduce metal ions to form nanoparticles and stabilize them acting as capping agents. In addition, by incorporating EPS to the metal nanoparticles, the EPS confers them biocompatibility. Thus, the present review describes the main bacterial EPS utilized in the synthesis and stabilization of metal nanoparticles, the mechanisms involved in this process, and the different applications of these nanoparticles, emphasizing in their biomedical applications.

Metal removal and reduction potential of an exopolysaccharide produced by Arctic psychrotrophic bacterium Pseudomonas sp. PAMC 28620

Metal reducing potential of an exopolysaccharide (EPS) produced by Arctic glacier soil bacteriumPseudomonassp. PAMC 28620.

Design, synthesis and in vitro evaluation of anticancer and antibacterial potential of surface modified Tb(OH)3@SiO2core–shell nanoparticles

In the current study, we modified the surface of Tb(OH)₃nanoparticles with a silica layer to enhance their solubility and biocompatibility.

Induction of intrinsic apoptotic pathway and cell cycle arrest via baicalein loaded iron oxide nanoparticles as a competent nano-mediated system for triple negative breast cancer therapy

Magnetic nanoparticles have shown an increasing number of applications in the field of molecular medicine.

Exopolysaccharide from psychrotrophic Arctic glacier soil bacterium Flavobacterium sp. ASB 3-3 and its potential applications

Exopolysaccharide from psychrotrophic Arctic glacier soil bacteriumFlavobacteriumsp. ASB 3-3.

In situ synthesis of silver nanoparticles dispersed or wrapped by a Cordyceps sinensis exopolysaccharide in water and their catalytic activity

In situ synthesis of silver nanoparticles (AgNPs) dispersed or wrapped by a Cordyceps sinensis exopolysaccharide (EPS) and their catalytic activity.