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1.
ACS Nano ; 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-39282795

RESUMO

Increasing accumulation of nanoplastics across ecosystems poses a significant threat to both terrestrial and aquatic life. Surface-enhanced Raman scattering (SERS) is an emerging technique used for nanoplastics detection. However, the identification and classification of nanoplastics using SERS faces challenges regarding sensitivity and accuracy as nanoplastics are sparsely dispersed in the environment. Metal-phenolic networks (MPNs) have the potential to rapidly concentrate and separate various types and sizes of nanoplastics. SERS combined with machine learning may improve prediction accuracy. Herein, we report the integration of MPNs-mediated separation with machine learning-aided SERS methods for the accurate classification and high-precision quantification of nanoplastics, which is tailored to include the complete region of characteristic peaks across diverse nanoplastics in contrast to the traditional manual analysis of SERS spectra on a singular characteristic peak. Our customized machine learning system (e.g., outlier detection, classification, quantification) allows for the identification of detectable nanoplastics (accuracy 81.84%), accurate classification (accuracy > 97%), and sensitive quantification of various types of nanoplastics (polystyrene (PS), poly(methyl methacrylate) (PMMA), polyethylene (PE), and poly(lactic acid) (PLA)) down to ultralow concentrations (0.1 ppm) as well as accurate classification (accuracy > 92%) of nanoplastic mixtures at a subppm level. The effectiveness of this approach is substantiated by its ability to discern between different nanoplastic mixtures and detect nanoplastic samples in natural water systems.

2.
Compr Rev Food Sci Food Saf ; 23(5): e13415, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39267152

RESUMO

The article explores the science and practice of electrospinning, tracing its history and examining the factors that influence fiber morphology, including the solution composition, processing conditions, and environmental conditions. It offers a thorough examination of electrospinning fundamentals geared toward generating an appropriate platform for creating tailored nanofibers for sensing applications in the food industry. These nanofibers play a critical role in food analysis, sensing, and traceability, and we highlight their effectiveness in identifying pesticide residues, food components, antibiotics, heavy metals, and foodborne pathogens as well as in monitoring the freshness and spoilage of food. The use of electrospinning technology is poised to make sensing platforms more accessible, affordable, and widespread, thereby significantly contributing to the improvement of food quality and safety monitoring practices.


Assuntos
Nanofibras , Nanofibras/química , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Análise de Alimentos/métodos
3.
Molecules ; 29(18)2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39339410

RESUMO

Food contamination has emerged as a significant global health concern, posing substantial challenges to the food industry. Bacteria are the primary cause of foodborne diseases. Consequently, it is crucial to develop accurate and efficient sensing platforms to detect foodborne bacteria in food products. Among various detection methods, biosensors have emerged as a promising solution due to their portability, affordability, simplicity, selectivity, sensitivity, and rapidity. Electrospun nanofibers have gained increasing popularity in enhancing biosensor performance. These nanofibers possess a distinctive three-dimensional structure, providing a large surface area and ease of preparation. This review provides an overview of the electrospinning technique, nanofibers and nanofiber-based biosensors. It also explores their mechanisms and applications in the detection of foodborne bacteria such as Salmonella, Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas putida (P. putida).


Assuntos
Técnicas Biossensoriais , Microbiologia de Alimentos , Nanofibras , Técnicas Biossensoriais/métodos , Nanofibras/química , Microbiologia de Alimentos/métodos , Bactérias/isolamento & purificação , Contaminação de Alimentos/análise , Doenças Transmitidas por Alimentos/microbiologia , Humanos
4.
J Agric Food Chem ; 72(40): 22349-22359, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39327911

RESUMO

It is a big challenge to monitor pathogens in food with high selectivity. In this study, we reported an ultrasensitive method for Escherichia coli O157:H7 detection based on immunomagnetic separation and labeled surface-enhanced Raman scattering (SERS). The bacterium was identified by heterogeneous recognition elements, monoclonal antibody (mAb), and aptamer. E. coli O157:H7 was separated and enriched by magnetic nanoparticles modified by mAb, and then a plasmonic nanostructure functionalized by aptamers with embedded Raman tags and interior gaps was utilized for further discrimination and detection. The selectivity was enhanced by two binding sites. The higher Raman enhancement was obtained by strong local electromagnetic field oscillation in the gap and the firm embedment of 4-mercaptopyridine (4-Mpy). Optimum experiments created that SERS signals of 4-Mpy at 1010 cm-1 had a good linearity with E. coli O157:H7 at a large range of 10 to 107 CFU/mL with a limit of detection of 2 CFU/mL. This method has great potential for on-site food pathogenic bacterial detection.


Assuntos
Escherichia coli O157 , Contaminação de Alimentos , Separação Imunomagnética , Análise Espectral Raman , Escherichia coli O157/isolamento & purificação , Análise Espectral Raman/métodos , Separação Imunomagnética/métodos , Contaminação de Alimentos/análise , Limite de Detecção , Anticorpos Monoclonais/química , Microbiologia de Alimentos/métodos
5.
Food Chem ; 463(Pt 3): 141227, 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39316900

RESUMO

This study aims to investigate the physical stability, droplet size, zeta potential, and antimicrobial properties of nanoemulsions formulated with betel leaf extract using ß-cyclodextrin (CD) and sodium alginate (SA) biopolymers. Nanoemulsions with ß-cyclodextrin exhibit superior stability at lower temperatures, with limited droplet size, and strong electrostatic repulsion. Morphological images demonstrate the successful encapsulation of betel leaf extract within both biopolymers, highlighting their potential for antimicrobial applications. Both CD and SA nanoemulsions display inhibitory effects on bacterial strains (E. coli, P. aeruginosa, L. monocytogenes, S. aureus, and B. cereus) and fungal growth (A. brasiliensis, R. stolonifer, F. oxysporum, and C. albicans). SA nanoemulsions show higher antimicrobial activity due to H+ ion release, particularly against A. brasiliensis and C. albicans. These findings underscore the potential of betel leaf extract nanoemulsions, especially those with SA, for various antimicrobial applications for sustainable food packaging, highlighting their significance in addressing microbial challenges.

6.
Opt Lett ; 49(17): 4835-4838, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39207976

RESUMO

A key challenge in realizing ultrahigh-resolution displays is the efficient preparation of ultrasmall-sized (USS) light-emitting diodes (LEDs). Today, GaN-based LEDs are mainly prepared through dry etching processes. However, it is difficult to achieve efficient and controllable etching of USS LED with high aspect ratios, and LED sidewalls will appear after etching, which will have a negative impact on the device itself. Herein, a method for preparing USS LED based on GaN epitaxial wafers is reported (on two types of wafers, i.e., with p-GaN fully activated and unactivated). F-ions are injected into the intentionally exposed areas on the two types of wafers to achieve device isolation. The area under the micro-/nano-sized protective masks (0.5, 0.8, 1, 3, 5, 7, 9, and 10 µm wide Ni/Au stripes) are the LED lighting areas. The LED on the p-GaN unactivated wafer (UAW) requires further activation. The Ni/Au mask not only serves as the p-electrode of LED but also Ni as a hydrogen (H) removing metal covering the surface of p-GaN UAW that can desorb H from a Mg element in the film at relatively low temperatures, thereby achieving the selective activation of LED lighting areas. Optoelectronic characterization shows that micro-/nano-sized LED arrays with individual-pixel control were successfully fabricated on the two types of wafers. It is expected that the demonstrated method will provide a new way toward realizing ultrahigh-resolution displays. Analyzing the changes in the current flowing through LED (before and after selective activation) on the F-injected p-GaN UAW, it is believed that depositing H removing metal on p-GaN UAW could possibly realize the device array through the selective activation only (i.e., without the need for ion implantation), offering a completely new insight.

7.
Adv Food Nutr Res ; 111: 215-259, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39103214

RESUMO

In this contemporary era, with over 8 billion people worldwide, ensuring food safety has become more critical than ever. To address this concern, the introduction of intelligent packaging marks a significant breakthrough. Essentially, this innovation tackles the challenge of rapid deterioration in perishable foods, which is vital to the well-being of communities and food safety. Unlike traditional methods that primarily emphasize shelf-life extension, intelligent packaging goes further by incorporating advanced sensing technologies to detect signs of spoilage and contamination in real-time, such as changes in temperature, oxygen levels, carbon dioxide levels, humidity, and the presence of harmful microorganisms. The innovation can rely on various packaging materials like plastics, metals, papers, or biodegradable polymers, combined with sophisticated sensing techniques such as colorimetric sensors, time-temperature indicators, radio-frequency identification tags, electronic noses, or biosensors. Together, these elements form a dynamic and tailored packaging system. This system not only protects food from spoilage but also offers stakeholders immediate and adequate information about food quality. Moreover, the real-world application on seafood, meat, dairy, fruits, and vegetables demonstrates the feasibility of using intelligent packaging to significantly enhance the safety and shelf life of a wide variety of perishable goods. By adopting intelligent packaging for smart sensing solutions, both the food industry and consumers can significantly reduce health risks linked with contamination and reduce unnecessary food waste. This underscores the crucial role of intelligent packaging in modern food safety and distribution systems, showcasing an effective fusion of technology, safety, and sustainability efforts aimed at nourishing a rapidly growing global population.


Assuntos
Embalagem de Alimentos , Inocuidade dos Alimentos , Embalagem de Alimentos/métodos , Humanos , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Técnicas Biossensoriais/métodos
8.
ACS Sens ; 9(9): 4662-4670, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39133267

RESUMO

The accumulation of micro/nanoplastics (MNPs) in ecosystems poses tremendous environmental risks for terrestrial and aquatic organisms. Designing rapid, field-deployable, and sensitive devices for assessing the potential risks of MNPs pollution is critical. However, current techniques for MNPs detection have limited effectiveness. Here, we design a wireless portable device that allows rapid, sensitive, and on-site detection of MNPs, followed by remote data processing via machine learning algorithms for quantitative fluorescence imaging. We utilized a supramolecular labeling strategy, employing luminescent metal-phenolic networks composed of zirconium ions, tannic acid, and rhodamine B, to efficiently label various sizes of MNPs (e.g., 50 nm-10 µm). Results showed that our device can quantify MNPs as low as 330 microplastics and 3.08 × 106 nanoplastics in less than 20 min. We demonstrated the applicability of the device to real-world samples through determination of MNPs released from plastic cups after hot water and flow induction and nanoplastics in tap water. Moreover, the device is user-friendly and operative by untrained personnel to conduct data processing on the APP remotely. The analytical platform integrating quantitative imaging, customized data processing, decision tree model, and low-cost analysis ($0.015 per assay) has great potential for high-throughput screening of MNPs in agrifood and environmental systems.


Assuntos
Microplásticos , Tecnologia sem Fio , Microplásticos/análise , Tecnologia sem Fio/instrumentação , Rodaminas/química , Zircônio/química , Taninos/análise , Taninos/química , Análise Custo-Benefício , Imagem Óptica/instrumentação , Aprendizado de Máquina
9.
Anal Sci Adv ; 5(5-6): e2300065, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38948319

RESUMO

Increasing concerns about global food safety and security demands innovative solutions, particularly in food packaging technologies. This review paper investigates the advanced integration of natural colourimetric sensors with biopolymer-based packaging materials, with a focus on developments over the past 5 years. These sensors change colour in response to environmental stimuli such as oxygen, temperature, pH and relative humidity, intuitively indicating food freshness and safety. The paper emphasizes the recent advancements in using natural colourants, such as alizarin, anthocyanins, betacyanins, chlorophyll, curcumin and shikonin. When combined with either natural or synthetic biopolymers, these colourants contribute to a sustainable and eco-friendly approach to food packaging. Such technological advances could notably decrease the incidence of foodborne illnesses by signaling potential spoilage or contamination, while also addressing food wastage by providing clear indications of edibility. Although challenges remain in sensor longevity and widespread adoption, the prospects for biopolymer-based food packaging with embedded natural colourimetric sensors are promising.

10.
Int J Biol Macromol ; 274(Pt 2): 133185, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38880462

RESUMO

The present research was conducted to explore the potential of mango kernel starch from the Chaunsa variety to develop starch and starch nanoparticles (SNPs) based films. The investigation included starch isolation from mango kernel followed by the preparation of SNPs by acid hydrolysis and a thorough examination of various physicochemical properties for film formation. The properties of SNPs were found to be distinctly different from those of native starch. SNPs exhibited an aggregated form with an irregular surface, whereas native starch had an oval and elongated shape with a smooth surface. X-ray diffraction (XRD) analysis confirmed that the starch type in SNPs was of the A-type. Additionally, the pasting properties of SNPs were minimal due to the acid hydrolysis process. SNP-based composite film was developed with (5 %) SNP concentration added. This successful incorporation of SNPs enhanced biodegradability, with complete degradation occurring within three weeks. Moreover, the composite films displayed increased burst strength, measuring 1303.51 ± 73.7 g, and lower water vapor transmission rates (WVTR) at (7.40 ± 0.50) × 10-3 g per square meter per second and reduced water solubility at 35.32 ± 3.0 %. This development represents a significant advancement in the field of eco-friendly packaging materials.


Assuntos
Mangifera , Nanopartículas , Amido , Amido/química , Mangifera/química , Nanopartículas/química , Hidrólise , Solubilidade , Difração de Raios X , Embalagem de Alimentos/métodos
11.
Int J Biol Macromol ; 270(Pt 2): 132220, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38754654

RESUMO

Developing an edible and active coating, incorporating environmentally-friendly antimicrobial agents into edible polymers, provides an eco-friendly alternative to conventional packaging and exhibits significant potential in preserving the quality of postharvest food. Herein, we aim to develop a novel edible and active coating based on xanthan gum (XG) nanoemulsion (NE) incorporating betel leaf extract (BLE) for the preservation of fresh produce. The total phenolic content, total flavonoid content, and antioxidant capacity of the methanol extract of BLE at various concentrations were characterized. Further development of the active coating at different formulations of Tween 80 (1 % and 3 % w/v), XG (0.1 % to 0.5 % w/v), and BLE (1 % to 5 % w/v) was characterized by physical stability, viscosity, and antimicrobial properties. Results showed that the active coating at 1 % BLE showed significant antimicrobial properties against diverse bacterial and fungal foodborne pathogens (e.g., B. cereus, S. aureus) and fungal cultures (e.g., C. albicans). The study also examined the shelf-life of tomatoes coated with the BLE-XG NE solution, stored at 4 °C for 27 days. Analyses of weight retention, soluble solids, pH, texture, sensory attributes, and microbial populations showed that the coating effectively preserved tomato quality, highlighting its potential to preserve fresh produce and enhance food security.


Assuntos
Emulsões , Conservação de Alimentos , Extratos Vegetais , Folhas de Planta , Polissacarídeos Bacterianos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/farmacologia , Folhas de Planta/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Conservação de Alimentos/métodos , Antioxidantes/farmacologia , Antioxidantes/química , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Viscosidade , Solanum lycopersicum/química , Testes de Sensibilidade Microbiana
12.
J Hazard Mater ; 470: 134194, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38583196

RESUMO

The escalating prevalence of nanoplastics contamination in environmental ecosystems has emerged as a significant health hazard. Conventional analytical methods are suboptimal, hindered by their inefficiency in analyzing nanoplastics at low concentrations and their time-intensive processes. In this context, we have developed an innovative approach that employs luminescent metal-phenolic networks (L-MPNs) coupled with surface-enhanced Raman spectroscopy (SERS) to separate and label nanoplastics, enabling rapid, sensitive and quantitative detection. Our strategy utilizes L-MPNs composed of zirconium ions, tannic acid, and rhodamine B to uniformly label nanoplastics across a spectrum of sizes (50-500 nm) and types (e.g., polystyrene, polymethyl methacrylate, polylactic acid). Rhodamine B (RhB) functions as a Raman reporter within these L-MPNs-based SERS tags, providing the requisite sensitivity for trace measurement of nanoplastics. Moreover, the labeling with L-MPNs aids in the efficient separation of nanoplastics from liquid media. Utilizing a portable Raman instrument, our methodology offers cost-effective, swift, and field-deployable detection capabilities, with excellent sensitivity in nanoplastic analysis and a detection threshold as low as 0.1 µg/mL. Overall, this study proposes a highly promising strategy for the robust and sensitive analysis of a broad spectrum of particle analytes, underscored by the effective labeling performance of L-MPNs when coupled with SERS techniques.

13.
J Hazard Mater ; 465: 133161, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38103291

RESUMO

The increasing global demand for tellurium, driven by its critical role in alloys, photovoltaic devices, and electronics, has raised concerns about its environmental pollution and neurotoxicity. In response, the potential of alginic acid (AA), a renewable, low-cost, and sustainable biopolymer, was explored for the biosynthesis of ultra-small silver nanoparticles (AgNPs) and their application in the detection of tellurium (Te(IV)). The effect of key synthesis parameters on desired physicochemical properties and yield of AgNPs was established to ensure high specificity and sensitivity towards Te(IV). The purified AgNPs with AA surface ligands were utilized to demonstrate a ratiometric absorbance sensor that exhibits excellent linearity and nanomolar-level affinity. This approach achieved a high correlation coefficient of ∼ 0.982, with a low detection limit of about 22 nM. Further investigations into the effect of pH, ionic strength, and organic molecules were conducted to elucidate detection performance and molecular understanding. The detection mechanism relies on the coordination between Te(IV) ions and the carboxylate groups of AA, which initiates aggregation-induced plasmon coupling in adjacent AgNPs. The capability of this analytical method to monitor Te(IV) in real-world water samples features its rapidity, user-friendliness, and suitability for point-of-care monitoring, making it a promising alternative to more complex techniques.

14.
Biosensors (Basel) ; 13(7)2023 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-37504153

RESUMO

DNA hydrogels have gained significant attention in recent years as one of the most promising functional polymer materials. To broaden their applications, it is critical to develop efficient methods for the preparation of bulk-scale DNA hydrogels with adjustable mechanical properties. Herein, we introduce a straightforward and efficient molecular design approach to producing physically pure DNA hydrogel and controlling its mechanical properties by adjusting the degree of hydrogen bonding in ultralong single-stranded DNA (ssDNA) precursors, which were generated using a dual rolling circle amplification (RCA)-based strategy. The effect of hydrogen bonding degree on the performance of DNA hydrogels was thoroughly investigated by analyzing the preparation process, morphology, rheology, microstructure, and entrapment efficiency of the hydrogels for Au nanoparticles (AuNPs)-BSA. Our results demonstrate that DNA hydrogels can be formed at 25 °C with simple vortex mixing in less than 10 s. The experimental results also indicate that a higher degree of hydrogen bonding in the precursor DNA resulted in stronger internal interaction forces, a more complex internal network of the hydrogel, a denser hydrogel, improved mechanical properties, and enhanced entrapment efficiency. This study intuitively demonstrates the effect of hydrogen bonding on the preparation and properties of DNA hydrogels. The method and results presented in this study are of great significance for improving the synthesis efficiency and economy of DNA hydrogels, enhancing and adjusting the overall quality and performance of the hydrogel, and expanding the application field of DNA hydrogels.


Assuntos
DNA de Cadeia Simples , Nanopartículas Metálicas , Ouro , Hidrogéis/química , Ligação de Hidrogênio , Técnicas de Amplificação de Ácido Nucleico/métodos , DNA/química
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 301: 122954, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37270975

RESUMO

Pesticide active ingredients (AIs) are often applied with adjuvants to facilitate the stability and functionality of AIs in agricultural practice. The objective of this study is to investigate the role of a common non-ionic surfactant, alkylphenol ethoxylate (APEO), on the surface-enhanced Raman spectroscopic (SERS) analysis of pesticides as well as its impact on pesticide persistence on apple surfaces, as a model fresh produce surface. The wetted areas of two AIs (thiabendazole and phosmet) mixed with APEO were determined respectively to correct the unit concentration applied on apple surfaces for a fair comparison. SERS with gold nanoparticle (AuNP) mirror substrates was applied to measure the signal intensity of AIs with and without APEO on apple surfaces after a short-term (45 min) and a long-term (5 days) exposure. The limit of detection (LOD) of thiabendazole and phosmet using this SERS-based method were 0.861 ppm and 2.883 ppm, respectively. The result showed that APEO decreased the SERS signal for non-systemic phosmet, while increased SERS intensity of systemic thiabendazole on apple surfaces after 45 min pesticide exposure. After 5 days, the SERS intensity of thiabendazole with APEO was higher than thiabendazole alone, and there was no significant difference between phosmet with and without APEO. Possible mechanisms were discussed. Furthermore, a 1% sodium bicarbonate (NaHCO3) washing method was applied to test the impact of APEO on the persistence of the residues on apple surfaces after short-term and long-term exposures. The results indicated that APEO significantly enhanced the persistence of thiabendazole on plant surfaces after a 5-day exposure, while there was no significant impact on phosmet. The information obtained facilitates a better understanding of the impact of the non-ionic surfactant on SERS analysis of pesticide behavior on and in plants and helps further develop the SERS method for studying complex pesticide formulations in plant systems.


Assuntos
Malus , Nanopartículas Metálicas , Praguicidas , Fosmet , Praguicidas/análise , Malus/química , Fosmet/análise , Tensoativos , Ouro/química , Tiabendazol/análise , Nanopartículas Metálicas/química , Lipoproteínas
16.
Nanoscale ; 15(9): 4420-4428, 2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36749348

RESUMO

Based on transfer printing technology, micro-LED pixels can be transferred to different types and sizes of driving substrates to realize displays with different application scenarios. To achieve a successful transfer, GaN-based micro-LEDs first need to be separated from the original epitaxial substrate. Here, micro-LED pixels (each size 25 µm × 30 µm) on the sapphire substrate were transferred to a flexible semiconductor wafer processing (SWP) tape that is strongly sticky by conventional laser lift-off (LLO) techniques. The pixels on the SWP tape were then transferred by using a sacrificial layer of non-crosslinked oligomeric polystyrene (PS) film onto the intermediate and rigid substrate (IRS) with weak and tunable adhesion by thiol (-SH) modification. The electrode of the micro-LED is Au metal, which forms Au-S bonds with the surface of the IRS to fix the pixels. The rigid substrate helps ensure that the pixel spacing is almost unchanged during the stamp transfer process, and the weak and tunable adhesion facilitates the pixels being picked up by the stamp. The experimental results demonstrate that the pixels can be efficiently transferred to the IRS by LLO and sacrificial layer-assistance, which will provide the possibility of achieving the further transfer of pixels to different types and sizes of driving substrates by a suitable transfer stamp. The transfer process details are discussed, which can provide insights into the transfer of micro-nano devices through polymer sacrificial layers.

17.
Polymers (Basel) ; 14(10)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35631869

RESUMO

At present, people more actively pursuing biodegradable-based food packaging to lower the environmental problems of plastic-based packaging. Starch could become a promising alternative to plastic because of its properties (easily available, nontoxic, tasteless, biodegradable, ecofriendly, and edible). This review article is focused mainly on the impact of the properties of starch-based biodegradable films, such as their thickness, morphology, and optical, water-barrier, mechanical, oxygen-barrier, antioxidant, and antimicrobial properties, after the incorporation of additives, and how such films fulfill the demands of the manufacturing of biodegradable and edible food-based film with preferable performance. The incorporation of additives in starch-based films is largely explained by its functioning as a filler, as shown via a reduction in water and oxygen permeability, increased thickness, and better mechanical properties. Additives also showed antimicrobial and antioxidant properties in the films/coatings, which would positively impact the shelf life of coated or wrapped food material.

18.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120239, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34358786

RESUMO

Antibiotic resistant bacteria pose an increasing threat to global public health, and it is essential that effective detection methods for identifying these organisms. This study assesses the ability of three different analytical approaches that were developed using surface-enhanced Raman spectroscopy (SERS) to differentiate between antibiotic sensitive and resistant bacteria based on their responses to ampicillin exposure, using Escherichia coli O157:H7 as a model bacterium. The approaches tested in this study included a conventional SERS approach of mixing a droplet of bacterial culture with gold nanoparticles, extracellular matrix analysis, and in situ mapping of bacterial cells on a filter membrane. All three of the SERS techniques were able to differentiate between the sensitive and resistant bacterial strains based on peak intensity changes associated with compounds released by the bacteria in response to antibiotic exposure, with extracellular matrix analysis and filter mapping both observed to be more effective than the conventional approach. However, there were significant differences between the spectra obtained from the different techniques and the potential advantages and disadvantages of each approach should be considered when used in the future. This study shows that SERS can be an effective technique for rapid and efficient assessment of ampicillin sensitivity in E. coli, and more work should be done to explore these analytical approaches with other types of bacterial samples.


Assuntos
Escherichia coli O157 , Nanopartículas Metálicas , Ampicilina/farmacologia , Ouro , Análise Espectral Raman
19.
Nat Nanotechnol ; 16(3): 251-265, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33712739

RESUMO

Nanotechnology-adapted detection technologies could improve the safety and quality of foods, provide new methods to combat fraud and be useful tools in our arsenal against bioterrorism. Yet despite hundreds of published studies on nanosensors each year targeted to the food and agriculture space, there are few nanosensors on the market in this area and almost no nanotechnology-enabled methods employed by public health agencies for food analysis. This Review shows that the field is currently being held back by technical, regulatory, political, legal, economic, environmental health and safety, and ethical challenges. We explore these challenges in detail and provide suggestions about how they may be surmounted. Strategies that may have particular effectiveness include improving funding opportunities and publication venues for nanosensor validation, social science and patent landscape studies; prioritizing research and development of nanosensors that are specifically designed for rapid analysis in non-laboratory settings; and incorporating platform cost and adaptability into early design decisions.


Assuntos
Agricultura/tendências , Técnicas Biossensoriais/tendências , Nanotecnologia/tendências , Análise de Alimentos/métodos , Inocuidade dos Alimentos , Humanos
20.
ACS Appl Mater Interfaces ; 13(1): 1398-1412, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33398990

RESUMO

Nanotechnology-based packaging may improve food quality and safety, but packages manufactured with polymer nanocomposites (PNCs) could be a source of human dietary exposure to engineered nanomaterials (ENMs). Previous studies showed that PNCs release ENMs to foods predominantly in a dissolved state, but most of this work used food simulants like dilute acetic acid and water, leaving questions about how substances in real foods may influence exposure. Here, we demonstrate that food and beverage ingredients with reducing properties, like sweeteners, may alter exposure by inducing nanoparticle formation in foods contacting silver nanotechnology-enabled packaging. We incorporated 12.8 ± 1.4 nm silver nanoparticles (AgNPs) into polyethylene and stored media containing reducing ingredients in packages manufactured from this material under accelerated room-temperature and refrigerated conditions. Analysis of the leachates revealed that reducing ingredients increased the total silver transferred to foods contacting PNC packaging (by as much as 7-fold) and also induced the (re)formation of AgNPs from this dissolved silver during storage. AgNP formation was also observed when Ag+ was introduced to solutions of natural and artificial sweeteners (glucose, sucrose, aspartame), commercial beverages (soft drinks, juices, milk), and liquid foods (yogurt, starch slurry), and the amount and morphology of reformed AgNPs depended on the ingredient formulation, silver concentration, storage conditions, and light exposure. These results imply that food and beverage ingredients may influence dietary exposure to nanoparticles when PNCs are used in packaging applications, and the practice of using food simulants may in certain cases underpredict the amount of ENMs likely to be found in foods stored in these materials.


Assuntos
Bebidas , Embalagem de Alimentos , Nanopartículas Metálicas/química , Prata/química , Animais , Aspartame/química , Temperatura Baixa , Contaminação de Alimentos/análise , Glucose/química , Nanopartículas Metálicas/análise , Oxirredução , Polietileno/química , Prata/análise , Amido/química , Sacarose/química , Edulcorantes/química , Iogurte
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