Raul Carrera Cerritos

This study presents the green synthesis of suspended gold nanoparticles utilizing pomegranate juice and coffee extract, followed by the preparation of catalysts consisting of gold nanoparticles supported on vulcanized carbon (Au/XC72R). These catalysts were evaluated as anodes in paper-based microfluidic fuel cells fueled by glucose and human blood. Material characterization was performed using Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). The anode performance was assessed through measurements of maximum current density (MCD), open-circuit potential (OCP), and maximum power density (MPD). Additionally, the effect of heat treatment on cell performance was examined. Statistical analysis showed that, in the synthesis using coffee extract, temperature was the only significant factor affecting nanoparticle size, while synthesis time was the main factor for the pomegranate juice synthesis. The untreated Au/XC72R catalysts synthesized from both extracts exhibited superior electrocatalytic performance in microfluidic fuel cells operated with glucose and human blood. The highest OCP, MPD, and MCD values for the untreated catalysts were obtained with a 10 mM glucose solution. This was attributed to the presence of fine surface protrusions on the gold nanoparticles, which were partially lost upon heating and the increment of particle size. Overall, the results demonstrated that the green synthesis route employing pomegranate juice and coffee extract is effective and has potential for further optimization.

Objective: To evaluate, from the fruit of Guazuma ulmifolia L., its fructose content, its analytical constituents and also the functional groups present in the extract of its seed, with the aim of carrying out future biotechnological applications. Design/methodology/approach: In this work, the peel and seed extract, as well as the fiber obtained from the dried fruit of the tree of Guazuma ulmifolia L. From the peel extract, fructose and glucose were identified by the high-performance liquid chromatography, fructose was quantified by using a refractometer, the seed extract was analyzed by the Fourier transform infrared spectroscopy technique, and the dry fiber was evaluated bromatological to determine the analytical constituents. Results: High-performance liquid chromatography results corroborated the presence of fructose and glucose with retention times of 2.1 and 2.4 minutes, respectively. The greater area under the chromatogram for the retention time of 2.1 minutes indicated that the highest sugar concentration corresponds to fructose. The concentration of fructose in the extract obtained was 0.127 g/mL at the beginning of the extraction and 1.747 g/mL at the end of the extraction (110 minutes). The bromatological study indicated that the remaining biomass had a crude fiber content of 35.4% and a crude protein content of 7.12%. Limitations on study/implications: Being a seasonal fruit, an important limitation for this research work was the conservation and storage of the Guazuma ulmifolia L. fruit to carry out the different studies. Findings/conclusions: These results indicate that the biomass of Guazuma ulmifolia L., mainly from the dried fruit, is rich in carbohydrates and crude fiber with a potential for alternative application in livestock fodder, as well as its sugars as an alternative feed for honey bees.

The application of nanomaterials in the agri-food industry can lead us to the formulation of new sustainable and effective pesticides for the control of fungi such as Fusarium oxysporum f. sp. lycopersici (Fol). This is a fungal plant pathogen for the tomato plant. In this work, silver nanoparticles (AgNPs) were synthesized by a green methodology from Geranium leaf extract as a reducing agent. The poisoned food technique was used to determine the percentage of inhibition of Fol mycelial growth by the action of AgNPs. They were characterized by transmission electron microscopy (TEM, JEOL JEM-2100, Tokyo, Japan) and ultraviolet-visible spectroscopy (UV-VIS, DU 730 Beckman Coulter, Brea, CA, USA). Five different concentrations of AgNPs (10, 20, 40, 75, and 150 mg/L) were evaluated in vitro in order to determine the minimum inhibitory concentration (MIC) as well as the behavior of their antifungal activity in tomato fruit. Nanoparticles with spherical morphology and average diameters of 38.5 ± 18.5 nm were obtained. The maximum percentage of inhibition on the mycelial growth of Fol was 94.6 ± 0.1%, which was obtained using the AgNPs concentration of 150 mg/L and it was determined that the MIC corresponds to 75 mg/L. On the other hand, in a qualitative way, it was possible to observe an external inhibitory effect in the tomato fruit from the concentration of 10 mg/L. Finally, we can conclude that AgNPs are a viable alternative for alternative formulations applied in the agri-food industry as pesticide solutions.

Quality assurance in fresh food, as well as biosafety for human consumption has led us to develop technological alternatives that guarantee food safety in the face of the SARS-CoV-2 pandemic. An alternative is nanomaterials, which have multiple properties or mechanisms of action, such as antimicrobials, antifungals and / or antivirals, making them an alternative as a biocidal agent of great interest in the current pandemic that humanity is experiencing. nowadays. In this work, a preliminary study is presented on the in vitro antimicrobial action mechanism of aqueous extracts of lemon peel mixed with a colloidal solution of silver nanoparticles (AgNPs) biosynthesized from plant extracts, and with a range of diameters between 20 and 50 nm. The microbiological tests in Escherichia coli (ATCC 25922) demonstrated a growth inhibitory effect for all treatments with AgNPs, while for the extracts a reduced inhibitory effect was observed in disk diffusion and null for the test in nutritive broth. As a result of preliminary studies in lemons, we conclude that the use of nanotechnology in colloidal solution for the agricultural area promotes food safety and its application can be extended to other agricultural products susceptible to contamination.

The antimicrobial effects of silver (Ag) ions and salts are well known. However, the antimicrobial effects, mechanism, and the cytotoxic activity in vitro of Ag nanoparticles (AgNP) has recently been validated. In this work, we report the green synthesis of AgNPs using the extract of Eichhornia crassipes as a reducing agent and evaluate its antimicrobial activity against Escherichia coli (ATCC-25922). The morphology, size, chemical composition, and inhibition properties of the nanoparticles as a function of the reduction time and temperature were analyzed. According to TEM imaging, nanoparticles with average diameters between 20–40 nm were synthesized. Antibacterial results suggest that AgNPs can be used as an effective growth inhibitor with higher antimicrobial activity against Escherichia coli after 120 min of reaction with a synthesis temperature of 95°. More extensive analysis is required for the appropriate selection of the synthesis parameters and adequate concentration for use in biomedical applications and antibacterial control systems.

Metal nanoparticles are widely used in different areas such as biotechnology and biomedicine, for example in drug delivery, imaging and control of bacterial growth. The antimicrobial effect of silver has been identified as an alternative approach to the increasing bacterial resistance to antibiotics. Silver nanoparticles were synthesized by the green route using the Geranium extract as a reducing agent. The characterization was carried out by the techniques of UV-Vis spectrophotometry, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray emitted photoelectron spectroscopy (XPS) and X-ray diffraction. Nanoparticle diameters between 15 and 50 nm were obtained and the interplanar spaces calculated from the electron diffraction pattern corresponding to a mixture of silver with 4H and FCC structures. To determine the minimum inhibitory concentration of silver nanoparticles (AgNPs) on the Pseudomonas aeruginosa bacteria (ATCC-27853), different concentrations of colloidal solution 0.36, 0.18, 0.09 and 0.05 μg/mL were evaluated as a function of the incubation time, measuring the inhibition halo and colony forming unit (CFU) during 0, 2 and 4 h of incubation. The minimum inhibitory AgNPs concentration (MIC) is 0.36 μg/mL at 0 h while the concentration of 0.18 μg/mL presents a total inhibition of the bacterium after 2 h. For the rest of the dilutions, gradual inhibitions as a function of time were observed. We evaluate the antibacterial effect of silver nanoparticles obtained by a green methodology in Pseudomonas aeruginosa bacteria. Finally, the colloidal nanoparticle solution can be an antibacterial alternative for different biomedical approaches.

This work reports the effect of reduction temperature during the synthesis of PdAg catalysts through the polyol process and their evaluation in the ethanol electrooxidation reaction (EOR). The characterization was performed using Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD). The electrochemical evaluation for the ethanol electrooxidation reaction was implemented in alkaline medium using chronoamperometry (CA) and cyclic voltammetry (CV). An important effect of the reduction temperature on electroactivity and catalytic stability was observed: both the maximum current density and the catalytic stability were higher in the catalyst synthesized at the highest temperature (135°C). This performance was associated with the extent of the interaction between Pd and Ag which was measured in terms of the structural expansion of Pd.