Nanometer Size Research Articles

Hyperthermia on colorectal cancer: gold nanoshells-mediated photothermal therapy

Colon cancer or colorectal cancer is one of the most common malignant neoplasms in the world, characterized by uncontrolled cell growth on the colon mucosa. Treatment approaches depend primarily on the characteristics of the tumor´s localization, size, metastasis, and the health status of the patient. Nanomedicine shows itself as a novelty strategy to overcome the limitations of the therapies used in the clinic due to the disregard of the mechanisms associated with multidrug resistance because of the nanometric size of the particles utilized. Gold nanoshells are spheric structures of an approximate size of 30 nm, coated with an ultrathin gold layer that can absorb near-infrared light and convert it to thermal energy to produce hyperthermia on in vivo models of cancer tumors. Nanoparticles-assisted hyperthermia consists of control, direct, and specific heating against the tumor cells by nanoparticle irradiation with an external power source capable of increasing temperature to 39°C - 45°C without damaging surrounding healthy tissue. Compared with other nanomaterials, gold nanoshells show high biocompatibility and low cytotoxicity, which is why adjuvant chemotherapy and hyperthermia on gold nanoshells is a novel and promising approach for the treatment of colorectal cancer.

3D printed scaffolds as delivery devices for nanocrystals: A proof of concept loading Atorvastatin with enhanced properties for sublingual route of administration

Increasing the solubility of drugs is a recurrent objective of pharmaceutical research, and one of the most widespread strategies today is the formulation of nanocrystals (NCs). Beyond the many advantages of formulating NCs, their incorporation into solid dosage forms remains a challenge that limits their use. In this work, we set out to load Atorvastatin NCs (ATV-NCs) in a delivery device by combining 3D scaffolds with an “in situ” loading method such as freeze-drying. When comparing two infill patterns for the scaffolds at two different percentages, the one with the highest NCs load was chosen (Gyroid 20 % infill pattern, 13.8 ± 0.5 mg). Colloidal stability studies of NCs suggest instability in acidic media, and therefore, the system is postulated for use as a sublingual device, potentially bypassing stomach and hepatic first-pass effects. An ad hoc dissolution device was developed to mimic the release of actives. The nanometric size and properties acquired in the process were maintained, mainly in the dissolution rate and speed, achieving 100 % dissolution of the content in 180 s. Based on these results, the proof of concept represents an innovative approach to converting NCs suspensions into solid dosage forms.

New Chitosan-Based Co-Delivery Nanosystem for Diabetes Mellitus Therapy.

Type 2 diabetes mellitus (T2DM) is one of the most common metabolic disorders, with a major involvement of oxidative stress in its onset and progression. Pioglitazone (Pio) is an antidiabetic drug that mainly works by reducing insulin resistance, while curcumin (Cur) is a powerful antioxidant with an important hypoglycemic effect. Both drugs are associated with several drawbacks, such as reduced bioavailability and a short half-life time (Pio), as well as instability and poor water solubility (Cur), which limit their therapeutic use. In order to overcome these disadvantages, new co-delivery (Pio and Cur) chitosan-based nanoparticles (CS-Pio-Cur NPs) were developed and compared with simple NPs (CS-Pio/CS-Cur NPs). The NPs were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). In addition, the entrapment efficiency (EE) and loading capacity (LC), as well as the release profile, of the APIs (Pio and Cur) from the CS-APIs NPs in simulated fluids (SGF, SIF, and SCF) were also assessed. All the CS-APIs NPs presented a small particle size (PS) (211.6-337.4 nm), a proper polydispersity index (PI) (0.104 and 0.289), and a positive zeta potential (ZP) (21.83 mV-32.64 mV). Based on the TEM results, an amorphous state could be attributed to the CA-APIs NPs, and the TEM analysis showed a spherical shape with a nanometric size for the CS-Pio-Cur NPs. The FT-IR spectroscopy supported the successful loading of the APIs into the CS matrix and proved some interactions between the APIs and CS. The CS-Pio-Cur NPs presented increased or similar EE (85.76% ± 4.89 for Cur; 92.16% ± 3.79 for Pio) and LC% (23.40% ± 1.62 for Cur; 10.14% ± 0.98 for Pio) values in comparison with simple NPs, CS-Cur NPs (EE = 82.46% ± 1.74; LC = 22.31% ± 0.94), and CS-Pio NPs (EE = 93.67% ± 0.89; LC = 11.24% ± 0.17), respectively. Finally, based on the release profile results, it can be appreciated that the developed co-delivery nanosystem, CS-Pio-Cur NPs, assures a controlled and prolonged release of Pio and Cur from the polymer matrix along the GI tract.

Airborne Nanoparticle Concentrations Are Associated with Increased Mortality Risk in Canada's Two Largest Cities.

Outdoor fine particulate air pollution (PM2.5) contributes to millions of deaths around the world each year, but much less is known about the long-term health impacts of other particulate air pollutants including ultrafine particles (a.k.a. nanoparticles) which are in the nanometer size range (<100 nm), widespread in urban environments, and not currently regulated. Estimate the associations between long-term exposure to outdoor ultrafine particles and mortality. Outdoor air pollution levels were linked to the residential addresses of a large, population-based cohort from 2001 - 2016. Associations between long-term exposure to outdoor ultrafine particles and nonaccidental and cause-specific mortality were estimated using Cox proportional hazards models. An increase in long-term exposure to outdoor ultrafine particles was associated with an increased risk of nonaccidental mortality (Hazard Ratio = 1. 073, 95% Confidence Interval = 1. 061, 1. 085) and cause-specific mortality, the strongest of which was respiratory mortality (Hazard Ratio = 1.174, 95% Confidence Interval = 1.130, 1.220). Long-term exposure to outdoor ultrafine particles was associated with increased risk of mortality. We estimated the mortality burden for outdoor ultrafine particles in Montreal and Toronto, Canada to be approximately 1100 additional nonaccidental deaths every year. Furthermore, we observed possible confounding by particle size which suggests that previous studies may have underestimated or missed important health risks associated with ultrafine particles. As outdoor ultrafine particles are not currently regulated, there is great potential for future regulatory interventions to improve population health by targeting these common outdoor air pollutants.

Biocompatible PLGA-PCL nanobeads for efficient delivery of curcumin to lung cancer

Lung cancer has been mentioned as the first and second most prevalent cancer among males and females worldwide, respectively since conventional approaches do not have enough efficiency in its suppression. Therefore, a biocompatible and efficient polylactic-co-glycolic acid (PLGA: P)- poly-ε-caprolactone (PCL: P) copolymer was fabricated for delivery of relatively insoluble curcumin (Cur) to A549 lung cancer cells. Next, the physicochemical aspects of the synthesized nanobeads were characterized by applying analytical sets, including FT-IR, DLS, TEM, and TGA as nano-metric size (20–45 nm) and 1.29% of Cur entrapment efficiency were determined for P-P-Cur nano-beads. Thereafter, a controlled (5% within 2 h at pH 7.4) and pH-sensitive (nearly 50% within 4 h at pH 5.0) drug release manner was observed for P-P-Cur nanobeads. Thereafter, biomedical assays were conducted for the cancer suppression ability of nanobeads. 41% cell viability after 24 h of treatment with 200 nM concentration and 7.55% cell cycle arrest at 5 h of post-treatment with 100 nM (IC50) concentration were attained for P-P-Cur. Also, 7-fold increase and 2-fold decrease in the expressions of Caspase-9 (apoptotic gene) and Bcl2 (anti-apoptotic gene) were observed which have further approved the cancer inhibition potency of the P-P-Cur sample. The cellular uptake results indicated 91% internalization in A549 cells while it was less than 1% for the pure Cur. These data have demonstrated that P-P-Cur can use as a biocompatible drug delivery system for Cur and treatment of lung cancer.

Structural insight into palladium-nickel clusters over mordenite zeolite for carbene-insertion reaction

The advancement of heterogeneous catalysts incorporating metal clusters in the nanometric size range has garnered significant attention due to their extraordinary catalytic activity and selectivity. The detailed characterization and understanding of the atomic structure of these metal clusters within catalysts is crucial for elucidating the underlying reaction mechanisms. In the present study, a distinctive three-atom PdNi cluster, characterized by two Pd atoms at terminal positions and a central Ni atom, was synthesized over mordenite zeolite. The presence of atomic PdNi clusters within the eight-membered ring side pocket area was confirmed by multiple advanced analytical techniques, including magic-angle spinning nuclear magnetic resonance spectroscopy, synchrotron X-ray powder diffraction, extended X-ray absorption fine structure spectroscopy, and high-angle annular dark-field scanning transmission electron microscopy. The catalytic activity of the confined active species was examined by the carbene-mediated reactions of ethyl-2-diazoacetate to ethyl-2-methoxyacetate as a model reaction. Compared to the Pd-mordenite and Ni-mordenite, the PdNi-mordenite catalyst incorporates a PdNi cluster, which demonstrates a superior performance, achieving 100% conversion and high selectivity under the same reaction conditions. Our study elucidates the potential of constructing bimetallic clusters in zeolites, providing valuable insights for developing new heterogeneous catalysts applicable to a wide range of catalytic processes.

Use of Nanobubbles to Improve Mass Transfer in Bioprocesses

Nanobubble technology has emerged as a transformative approach in bioprocessing, significantly enhancing mass-transfer efficiency for effective microbial activity. Characterized by their nanometric size and high internal pressure, nanobubbles possess distinct properties such as prolonged stability and minimal rise velocities, allowing them to remain suspended in liquid media for extended periods. These features are particularly beneficial in bioprocesses involving aerobic strains, where they help overcome common obstacles, such as increased culture viscosity and diffusion limitations, that traditionally impede efficient mass transfer. For instance, in an experimental setup, nanobubble aeration achieved 10% higher soluble chemical oxygen demand (sCOD) removal compared to traditional aeration methods. Additionally, nanobubble-aerated systems demonstrated a 55.03% increase in caproic acid concentration when supplemented with air nanobubble water, reaching up to 15.10 g/L. These results underscore the potential of nanobubble technology for optimizing bioprocess efficiency and sustainability. This review delineates the important role of the mass-transfer coefficient (kL) in evaluating these interactions and underscores the significance of nanobubbles in improving bioprocess efficiency. The integration of nanobubble technology in bioprocessing not only improves gas exchange and substrate utilization but also bolsters microbial growth and metabolic performance. The potential of nanobubble technology to improve the mass-transfer efficiency in biotechnological applications is supported by emerging research. However, to fully leverage these benefits, it is essential to conduct further empirical studies to specifically assess their impacts on bioprocess efficacy and scalability. Such research will provide the necessary data to validate the practical applications of nanobubbles and identify any limitations that need to be addressed in industrial settings.

Development of nanobigel system combining apoptosis-inducing daidzein and flaxseed oil for the synergistic treatment of skin cancer

Daidzein (DDZ), an isoflavone containing phytoestrogen, and flaxseed oil (FSO), an omega-3-polyunsaturated fatty acid rich dietary lipid, are known to exert anticancer effects via inducing apoptosis in cancer cells. However, oral administration of DDZ and FSO is associated with biopharmaceutical issues. This study aimed to develop a stable topical bigel (BG) system containing DDZ and FSO to exert synergistic effects in the treatment of skin cancer. High speed homogenization method was used for the preparation of DDZ-loaded bigel (DDZ@BG). In vitro investigations and morphological studies were performed to characterize the developed formulation. MTT cytotoxicity tests were conducted to evaluate the effect of the combination of DDZ and FSO on A431human skin cancer cell lines. To assess the toxicity, skin irritation studies using the Draize test was performed followed by histopathological analysis. The optimized DDZ@BG exhibited uniform texture, nanometric size and high drug content with sustained release profile and improved drug permeation. The MTT cytotoxicity studies revealed an IC50 value of 110.2 μg/mL for the optimized formulation. The developed nanobigel formulation exhibited high potential in the effective topical treatment of skin cancer with improved safety profile.

Influence of meteoric smoke particles on the incoherent scatter measured with EISCAT VHF

Abstract. Meteoric ablation in the Earth's atmosphere produces particles of nanometer size and larger. These particles can become charged and influence the charge balance in the D region (60–90 km) and the incoherent scatter observed with radar from there. Radar studies have shown that, if enough dust particles are charged, they can influence the received radar spectrum below 100 km, provided the electron density is sufficiently high (&gt;109 m3). Here, we study an observation made with the EISCAT VHF radar on 9 January 2014 during strong particle precipitation so that incoherent scatter was observed down to almost 60 km altitude. We found that the measured spectra were too narrow in comparison to the calculated spectra. Adjusting the collision frequency provided a better fit in the frequency range of ± 10–30 Hz. However, this did not lead to the best fit in all cases, especially not for the central part of the spectra in the narrow frequency range of ±10 Hz. By including a negatively charged dust component, we obtained a better fit for spectra observed at altitudes of 75–85 km, indicating that dust influences the incoherent-scatter spectrum at D-region altitudes. The observations at lower altitudes were limited by the small number of free electrons, and observations at higher altitudes were limited by the height resolution of the observations. Inferred dust number densities range from a few particles up to 104 cm−3, and average sizes range from approximately 0.6 to 1 nm. We find an acceptable agreement with the dust profiles calculated with the WACCM-CARMA (Whole Atmosphere Community Climate Model-Community Aerosol Radiation Model for Atmospheres) model. However, these do not include charging, which is also based on models.

Lipid-based microemulsion gel for the topical delivery of methotrexate: an optimized, rheologically acceptable formulation with conducive dermatokinetics.

In the present study, we have formulated a methotrexate (MTX)-loaded microemulsion topical gel employing quality-by-design optimization. The optimized lipid-based microemulsion was incorporated into a 2% carbopol gel. The prepared formulation was characterized for micromeritics, surface charge, surface morphology, conductivity studies, rheology studies, texture analysis/spreadability, drug entrapment, and drug loading studies. The formulation was further evaluated for drug release and release kinetics, cytotoxicity assays, drug permeation and drug retention studies, and dermatokinetics. The developed nanosystem was not only rheologically acceptable but also offered substantial drug entrapment and loading. From drug release studies, it was observed that the nanogel showed higher drug release at pH 5.0 compared to plain MTX, plain gel, and plain microemulsion. The developed system with improved dermatokinetics, nanometric size, higher drug loading, and enhanced efficacy towards A314 squamous epithelial cells offers a huge promise in the topical delivery of methotrexate.

Synthesizing of cobalt oxide nanofibers and investigation of changes in synthesizing parameters on the final product

AbstractIn this study, the best conditions for synthesizing the cobalt oxide nanofibers using the electrospinning method was investigated. For this purpose, the effect of various factors such as solvent, calcination temperature, and polymer concentration on the crystal structure, morphology, and size of the synthesized samples was evaluated. An extensive characterization of the products was performed using x‐ray diffractometry, scanning electron microscopy, ultraviolet‐visible spectroscopy, and photoluminescence. X‐ray diffractometry results of fabricated samples at different temperatures confirm cobalt oxide synthesis. Scanning electron microscopy analysis shows that the best fibers are synthesized from a polymer solution prepared at room temperature with a dual solvent of deionized water and ethanol under a calcination temperature of 600 °C. Also, some shifts were observed by examining the optical properties using ultraviolet‐visible and photoluminescence spectroscopy. These results show that the proper selection of reaction conditions in the electrospinning method can be very effective for the synthesis of cobalt oxide fibers with morphology in nanometer sizes.

Preparation, Characterization, and Evaluation of the Anticancer Effect of Mesoporous Silica Nanoparticles Containing Rutin and Curcumin.

The aim of this study was the preparation of mesoporous silica nanoparticles co-loaded with rutin and curcumin (Rut-Cur-MSNs) and the assessment of its physicochemical properties as well as its cytotoxicity on the head and neck cancer cells (HN5). Besides, ROS generation of HN5 cells exposed to Rut-Cur-MSNs was evaluated. Several investigations showed that rutin and curcumin have potential effects as anticancer phytochemicals; however, their low aqueous solubility and poor bioavailability limited their applications. The assessment of physicochemical properties and anticancer effect of prepared nanoparticles was the objective of this study. The physicochemical properties of produced nanoparticles were evaluated. The toxicity of Rut-Cur-MSNs on HN5 cells was assessed. In addition, the ROS production in cells treated with Rut- Cur-MSNs was assessed compared to control untreated cells. The results showed that Rut-Cur-MSNs have mesoporous structure, nanometer size and negative surface charge. The X-ray diffraction pattern showed that the prepared nanoparticles belong to the family of silicates named MCM-41. The cytotoxicity of Rut-Cur-MSNs at 24 h was significantly higher than that of rutin-loaded MSNs (Rut-MSNs) and curcumin-loaded MSNs (Cur-MSNs) (p<0.05). The achieved results recommend that the prepared mesoporous silica nanoparticles containing rutin and curcumin can be a useful nanoformulation for the treatment of cancer. The produced nanomaterial in this study can be helpful for cancer therapy.

A promising eco-sustainable wound dressing based on cellulose extracted from Spartium junceum L. and impregnated with Glycyrrhiza glabra L extract: Design, production and biological properties

Glycyrrhiza glabra extract is widely known for its antioxidant and anti-inflammatory properties and can improve the wound healing process. The aim of this work was to shorten the time of the healing process by using an eco-sustainable wound dressing based on Spanish broom flexible cellulosic fabric by impregnation with G. glabra extract-loaded ethosomes. Chemical analysis of G. glabra extract was performed by LC-DAD-MS/MS and its encapsulation into ethosomes was obtained using the ethanol injection method. Lipid vesicles were characterized in terms of size, polydispersity index, entrapment efficiency, zeta potential, and stability. In vitro release studies, biocompatibility, and scratch test on 3T3 fibroblasts were performed. Moreover, the structure of Spanish broom dressing and its ability to absorb wound exudate was characterized by Synchrotron X-ray phase contrast microtomography (SR-PCmicroCT). Ethosomes showed a good entrapment efficiency, nanometric size, good stability over time and a slow release of polyphenols compared to the free extract, and were not cytotoxic. Lastly, the results revealed that Spanish broom wound dressing loaded with G. glabra ethosomes is able to accelerate wound closure by reducing wound healing time. To sum up, Spanish broom wound dressing could be a potential new green tool for biomedical applications.

Caseinate-coated zein nanoparticles as potential delivery vehicles for guavinoside B from guava: Molecular interactions and encapsulation properties

Guavinoside B (GUB) is a characteristic constituent from guava with strong antioxidant activity; however, its low water solubility limits its utilization. Herein, we investigated the interaction between GUB and zein, a prolamin with self-assembling property, using multiple spectroscopic methods and fabricated GUB-zein-NaCas nanoparticles (GUB-Z-N NPs) via the antisolvent coprecipitation approach. GUB caused fluorescence quenching to zein via the static quenching mechanism. Fourier-transform infrared spectroscopy and computational analysis revealed that GUB bound to zein via van der Waals interaction, hydrogen bond, and hydrophobic forces. The GUB-Z-N NPs were in the nanometric size range (< 200 nm) and exhibited promising encapsulation efficiency and redispersibility after freeze-drying. These particles remained stable for up to 31 days at 4 °C and great resistance to salt and pH variation, and displayed superior antioxidant activity to native GUB. The current study highlights the potential of zein-based nanoparticles as delivery vehicles for GUB in the food industry.

ADVANCEMENTS IN THERAPEUTICS: THE ROLE OF NANOPARTICLE-INFUSED HYDROGELS IN REVOLUTIONIZING DRUG DELIVERY

Nanoparticles loaded hydrogel has emerged as a promising strategy in the field of drug delivery systems, offering unique advantages in terms of controlled release, enhanced bioavailability, and targeted delivery of therapeutic agents. Nanoparticles, typically ranging from 1 to 100 nanometers in size, serve as carriers for drugs, encapsulating them within their matrix and protecting them from degradation. Hydrogels, on the other hand, are three-dimensional cross-linked networks of hydrophilic polymers capable of absorbing and retaining large amounts of water. It aims to provide a comprehensive understanding of nanoparticles loaded hydrogel in drug delivery systems by elucidating the relationship between nanoparticles and hydrogels and their synergistic effects on drug delivery. Firstly, the properties of nanoparticles, including size, surface charge, and composition, significantly influence their interactions with hydrogels and the encapsulation efficiency of drugs. Secondly, the unique characteristics of hydrogels, such as tunable swelling behavior and biocompatibility, complement the stability and sustained release kinetics of nanoparticles.Furthermore, the incorporation of nanoparticles into hydrogel matrices enhances their mechanical strength and allows for the development of stimuli-responsive systems, enabling on-demand drug release triggered by external stimuli such as pH, temperature, or magnetic fields. The synergistic combination of nanoparticles and hydrogels opens up new avenues for the design of advanced drug delivery systems with improved therapeutic efficacy and reduced side effects. In conclusion, nanoparticles loaded hydrogel represents a promising platform for the development of next-generation drug delivery systems, offering unprecedented control over drug release kinetics and targeting capabilities. This review highlights the importance of understanding the interplay between nanoparticles and hydrogels in optimizing the performance of drug delivery systems for various biomedical applications.

Spark Discharge Aerosol-Generated Copper-Based Nanoparticles: Structural & Optical Properties; Application on the Antiviral (SARS-CoV-2) and Antibacterial Improvement of Face Masks.

Nanoparticle formation by Spark Discharge Aerosol Generation offers low-cost fabrication of nanoparticles, without the use of chemicals or vacuum. It produces aerosol particles of a few nanometers in size with high purity. In this work, copper-based -CuO (tenorite) and Cu- nanoparticles are produced, characterized and used to modify face mask air filters, achieving the introduction of antibacterial and antiviral properties. A range of characterization techniques have been employed, down to the atomic level. The majority of the particles are CuO (of a few nanometers in size that agglomerate to form aggregates), the remainder being a small number of larger Cu particles. The particles were deposited on various substrates, mainly fiber filters in order to study them and use them as biocidal agents. On face masks, their antibacterial activity against Escherichia coli (E.coli) results in a 100 % decrease in bacteria cell viability. Their antiviral activity on face masks results in a 90 % reduction of the Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) viability, 15 minutes post the application of the virus stock solution. This highlights the effectiveness of this approach, its simplicity, its low cost and its excellent environmental credentials.

Production of ultrafine particles with nanometer size distribution via a bubble film bursting method

Producing particles smaller than 50 nm continues to be a challenge for commonly used atomization techniques. In the present study, an atomization method based on bubble film bursting was proposed to generate ultrafine nanoparticles. The atomization solution added with surfactant was converted to big bubble with thin film, and three needles were employed to puncture the bubbles to produce small droplets. Droplets formed ultrafine nanoparticles after being dried by a diffusion dryer. The results showed that the median diameter of particles generated by bubble film bursting could be as low as 30 nm. The thinness of the bubble film played a significant role in producing small droplets. Additionally, the size distribution of particles was influenced by the NaCl concentration and the distance of the needle to orifice, as they altered the thickness of the bubbles. The bubble film bursting atomization method offers the advantage of producing ultrafine particles and holds potential for application in various fields.

Novel Synthesis of Nanocalcite from Phosphogypsum and Cesium Carbonate: Control and Optimization of Particle Size

This study investigates a controlled synthesis and particle size optimization of nanocalcite particles using phosphogypsum, a waste byproduct from the phosphate fertilizer industry, and cesium carbonate (Cs2CO3), a common carbonate source. The effects of synthesis parameters, including temperature and pH, on the size, morphology, and crystallinity of the synthesized nanocalcite particles were systematically examined. The optimized synthesis conditions for obtaining nanocalcite particles with desired properties are discussed. The synthesized nanocalcite particles were characterized using various techniques, such as XRD, FTIR, and SEM, to analyze their crystal structure, morphology, and elemental composition. Particle sizes were determined using the Debye–Scherrer method, and accordingly, nanometric sizes were achieved. The potential applications of the synthesized nanocalcite particles in cementitious materials, agriculture, and drug delivery are highlighted. This research provides valuable insights into the sustainable synthesis and size optimization of nanocalcite particles from phosphogypsum and Cs2CO3 at a controlled temperature and pH.

Ultrasound-Assisted Nanoemulsion Loaded with Optimized Antibacterial Essential Oil Blend: A New Approach against Escherichia coli, Staphylococcus aureus, and Salmonella Enteritidis in Trout (Oncorhynchus mykiss) Fillets.

This study aimed to obtain and characterize an oil-in-water nanoemulsion (NE) loaded with an in vitro optimized bactericidal essential oil blend of 50% oregano, 40% thyme, and 10% lemongrass and to evaluate its potential at three different concentrations (0.5%, 1%, and 2%) in the inactivation of Escherichia coli, Staphylococcus aureus, and Salmonella enterica serotype Enteritidis inoculated in rainbow trout fillets stored at 4 °C for 9 days. Regarding the NE, the nanometric size (<100 nm) with low polydispersion (0.17 ± 0.02) was successfully obtained through ultrasound at 2.09 W/cm2. Considering the three concentrations used, S. Enteritidis was the most susceptible. On the other hand, comparing the concentrations used, the NE at 2% showed better activity, reducing S. Enteritidis, E. coli, and S. aureus by 0.33, 0.20, and 0.73 log CFU/g, respectively, in the trout fillets. Thus, this data indicates that this is a promising eco-friendly alternative to produce safe fish for consumption and reduce public health risks.

INFLUENCE OF CELLULOSE NANOCRYSTALS ON POLYVINYL(PYRROLIDONE) GRAPHITE COMPOSITES

In this work, composites with poly vinyl(pyrrolidone), PVP, and graphite reinforced with cellulose nanocrystals, CNCs, were made. The CNCs had a nanometric size, with a hydrodynamic radius of 52 nm. FTIR analysis confirmed the presence of the characteristic functional groups of cellulose nanocrystals in the spectrum of pure CNCs. The PVP-graphite-CNC composites showed the characteristic peaks of PVP and graphite on the FTIR spectra, without the characteristic peaks of CNCs, which is explained by the incorporation of a small quantity of CNCs into the composites. However, the presence of CNCs increased the storage modulus of the composites by 70%, compared to the blank sample. The composites showed a glass transition temperature, attributed to PVP, and a tendency to increase with increasing CNC content; the highest CNC content caused a complex behaviour of glass transition temperature. To conclude, the addition of CNCs enhanced the mechanical properties of the composites.