An overview of antimicrobial nanoparticles for food preservation
01 Jul 2022-Materials Today: Proceedings-Vol. 72, pp 204-216
TL;DR: Nanotechnology opens up new possibilities for food innovation at an incredible rate, yet new technology needs evaluations of both potential negative impacts and numerous good effects as discussed by the authors , which is why it is important to evaluate the potential negative impact and potential good effects.
Abstract: Nanotechnology opens up new possibilities for food innovation at an incredible rate, yet new technology needs evaluations of both potential negative impacts and numerous good effects. We aimed to cover some of the latest breakthroughs in nanotechnology and their application to food processing in this overview. Applications of nanoparticles in the food sector are growing rapidly. Nanoparticles (NPs) play a significant role in enhancing food quality by protection and preservation and are preferred over traditional preservatives. In this work on organic and inorganic nanoparticles in various forms such as single and multiple metal oxides, polymeric nanocomposite, nanocapsules, etc., as well as various methods of their preparations are discussed. Nanoparticles in food are currently most explored for their antimicrobial applications; factors affecting their antimicrobial potential, their antimicrobial mechanisms, and laboratory methods applied to evaluate antimicrobial potentials are also discussed. Various properties of NPs in relevance to antimicrobial activities and methods used for their characterization are also discussed. Antimicrobial NPs used for the purpose in various ways such as active packaging, mixed in food, incorporated in edible film and coating, etc. discussed. In the current state NPs used in the food industry, have various concerns such as safety, and regulatory policies relevant to preparing, processing, packaging, and consumption are discussed. NPs do possess some functional properties and harmful effects as well in this relevant future perspective of antimicrobial NPs in food and their other applications explored in current work. Various aspects of the most intensively studied NPs as an antimicrobial in food technology such as silver oxide, and zinc oxide, are discussed.
TL;DR: In this paper , the potential use of ultrashort laser pulse processing of NPs and NPs-based thin films is discussed, with a focus on femtosecond laser pulses.
Abstract: The unique shape and size dependant properties of nanoparticles (NPs) are responsible for their emerging, extensive applications in everyday industry. The application of NP inks for printed flexible electronics requires an additional post processing step since the presence of additives and stabilizers in the NP based inks often results in inferior electrical properties of the printed patterns. Laser sintering is a well-established technique for past number of years and is extensively used with continuous wave (CW), long, and short pulsed lasers. The literature is enriched with conventional sintering methods however the field of ultrashort laser sintering is relatively under-reported compared to CW laser and nanosecond laser-based techniques. This study concisely focuses on the potential use of ultrashort laser pulse processing of NPs and NP based thin films. The review provides the recent advances on ultrashort lasers sintering with a key focus on femtosecond laser pulses. • The review presents a study of nanoparticles (NPs), their deposition and post processing techniques with a key focus on ultrashort laser sintering. • NPs and NPs based thin films are discussed. • Role of ultrashort pulses in laser sintering, laser crystallization and laser annealing is discussed. • Potential to use two-temperature phenomenon in thin film laser processing.
TL;DR: In this article , a pH-responsive self-gated antibacterial material is reported, which uses mesoporous silica nanomaterials as a carrier and achieves selfgating of the antibacterial agent through pH-sensitive imine bonds.
Abstract: In recent years, silica nanomaterials have been widely studied as carriers in the field of antibacterial activity in food. Therefore, it is a promising but challenging proposition to construct responsive antibacterial materials with food safety and controllable release capabilities using silica nanomaterials. In this paper, a pH-responsive self-gated antibacterial material is reported, which uses mesoporous silica nanomaterials as a carrier and achieves self-gating of the antibacterial agent through pH-sensitive imine bonds. This is the first study in the field of food antibacterial materials to achieve self-gating through the chemical bond of the antibacterial material itself. The prepared antibacterial material can effectively sense changes in pH values caused by the growth of foodborne pathogens and choose whether to release antibacterial substances and at what rate. The development of this antibacterial material does not introduce other components, ensuring food safety. In addition, carrying mesoporous silica nanomaterials can also effectively enhance the inhibitory ability of the active substance.
TL;DR: These nontoxic nanomaterials, which can be prepared in a simple and cost-effective manner, may be suitable for the formulation of new types of bactericidal materials.
Abstract: The antimicrobial activity of silver nanoparticles against E. coli was investigated as a model for Gram-negative bacteria. Bacteriological tests were performed in Luria-Bertani (LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of nanosized silver particles. These particles were shown to be an effective bactericide. Scanning and transmission electron microscopy (SEM and TEM) were used to study the biocidal action of this nanoscale material. The results confirmed that the treated E. coli cells were damaged, showing formation of "pits" in the cell wall of the bacteria, while the silver nanoparticles were found to accumulate in the bacterial membrane. A membrane with such a morphology exhibits a significant increase in permeability, resulting in death of the cell. These nontoxic nanomaterials, which can be prepared in a simple and cost-effective manner, may be suitable for the formulation of new types of bactericidal materials.
TL;DR: The results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.
Abstract: The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli, and Staphylococcus aureus. In these tests, Muller Hinton agar plates were used and Ag nanoparticles of various concentrations were supplemented in liquid systems. As results, yeast and E. coli were inhibited at the low concentration of Ag nanoparticles, whereas the growth-inhibitory effects on S. aureus were mild. The free-radical generation effect of Ag nanoparticles on microbial growth inhibition was investigated by electron spin resonance spectroscopy. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.
TL;DR: Standardized methods for determining minimum inhibitory concentrations and MBCs are described and like all standardized procedures, the method must be adhered to and may not be adapted by the user.
Abstract: Minimum inhibitory concentrations (MICs) are defined as the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation, and minimum bactericidal concentrations (MBCs) as the lowest concentration of antimicrobial that will prevent the growth of an organism after subculture on to antibiotic-free media. MICs are used by diagnostic laboratories mainly to confirm resistance, but most often as a research tool to determine the in vitro activity of new antimicrobials, and data from such studies have been used to determine MIC breakpoints. MBC determinations are undertaken less frequently and their major use has been reserved for isolates from the blood of patients with endocarditis. Standardized methods for determining MICs and MBCs are described in this paper. Like all standardized procedures, the method must be adhered to and may not be adapted by the user. The method gives information on the storage of standard antibiotic powder, preparation of stock antibiotic solutions, media, preparation of inocula, incubation conditions, and reading and interpretation of results. Tables giving expected MIC ranges for control NCTC and ATCC strains are also supplied.
TL;DR: An exhaustive list of in vitro antimicrobial susceptibility testing methods and detailed information on their advantages and limitations are reported.
Abstract: In recent years, there has been a growing interest in researching and developing new antimicrobial agents from various sources to combat microbial resistance. Therefore, a greater attention has been paid to antimicrobial activity screening and evaluating methods. Several bioassays such as disk-diffusion, well diffusion and broth or agar dilution are well known and commonly used, but others such as flow cytofluorometric and bioluminescent methods are not widely used because they require specified equipment and further evaluation for reproducibility and standardization, even if they can provide rapid results of the antimicrobial agent's effects and a better understanding of their impact on the viability and cell damage inflicted to the tested microorganism. In this review article, an exhaustive list of in vitro antimicrobial susceptibility testing methods and detailed information on their advantages and limitations are reported.
TL;DR: The data suggest that in addition to the release of toxic Cd(2+) ions from the particles also their surface chemistry, in particular their stability toward aggregation, plays an important role for cytotoxic effects.
Abstract: Cytotoxicity of CdSe and CdSe/ZnS nanoparticles has been investigated for different surface modifications such as coating with mercaptopropionic acid, silanization, and polymer coating. For all cases, quantitative values for the onset of cytotoxic effects in serum-free culture media are given. These values are correlated with microscope images in which the uptake of the particles by the cells has been investigated. Our data suggest that in addition to the release of toxic Cd 2+ ions from the particles also their surface chemistry, in particular their stability toward aggregation, plays an important role for cytotoxic effects. Additional patch clamp experiments investigate effects of the particles on currents through ion channels.