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Nanoparticles in Methane Production from Anaerobic Digesters
Published in Madan L. Verma, Nanobiotechnology for Sustainable Bioenergy and Biofuel Production, 2020
Efraín Reyes Cruz, Lilia Ernestina Montañez Hernández, Inty Omar Hernández De Lira, Nagamani Balagurusamy
Another way to study microbial development is the resazurin assay. This reagent act as an oxidation-reduction indicator that gives a specific signal that can be correlated with microbial activity. Resazurin reduction to resorufin and then to dihydroresorufin can only be done by living cells and not by the medium. Therefore, it can be suggested that a higher constant reduction rate of resazurin will show a faster microbial activity in anaerobic sludge. Kinetics of resazurin reduction, with Fe4NiO4Zn NPs addition, showed similar results in control (0.513 ± 0.028 mM/min) and 1 and 10 mg/L of Ni. When 100 mg/L of Ni was added, the reaction was significantly slower than the other treatments (0.488 ± 0.023 mM/min). In the case of Fe2NiO4 NPs addition, the kinetics of 1 and 10 mg/L of Ni were similar to control (0.577 ± 0.034 mM/min). However, the addition of 100 mg/L of Ni showed a faster kinetic (0.632 ± 0.018 mM/min) than the control. Then, all Fe4NiO4Zn NPs concentrations reduced microbial activity, while high concentrations of Fe2NiO4 NPs improved CH4 production and microbial activity even if the concentration of metals (Ni, Fe and Zn) remained between 0.04 and 0.08 mg/g-TSS in the liquid phase. With the addition of Fe4NiO4Zn NPs, Zn concentration remained stable at different concentrations, Ni was higher in 100 mg/L compared with 1 mg/l and Fe concentration in 100 mg/L of Ni was the highest in comparison with the other treatments (Chen et al. 2018).
Applications of Liquid Marbles
Published in Andrew Terhemen Tyowua, Liquid Marbles, 2018
Following incubation, the viability of cells in the marbles containing Fe3+ was measured by color change using AlmarBlue reagent or MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) colorimetric assay or DNA quantification and compared with those without the metal ion. In AlmarBlue colorimetric assay, a resazurin-based product (blue) is reduced to resofurin (red) in the presence of viable cells. Similarly, in the MTS assay, a tetrazolium salt is reduced to a formazan product with an associated color change of yellow to brown in the presence of viable cells. The intensity of the resultant color and DNA amount ratio (as compared with a marble containing phosphate buffer saline) was seen to decrease with increasing Fe3+ concentration as expected, indicative that cell viability decreases with Fe3+ concentration and that Fe3+ toxicity is concentration dependent. This shows that liquid marbles can be used for high-throughput drug screening of anchorage-dependent cells as well as other cell types.
Physical and biological properties of electrospun PCL meshes as a function of polymer concentration and voltage
Published in Paulo Jorge da Silva Bartolo, Fernando Moreira da Silva, Shaden Jaradat, Helena Bartolo, Industry 4.0 – Shaping The Future of The Digital World, 2020
E. Aslan, E. Daskalakis, C. Vyas, P. JDS. Bartolo
At day 1, all meshes were transferred to new plates, and fresh media added. Cell proliferation was measured using the Alamar Blue assay (Sigma-Aldrich, UK). Through this assay a fluorescent signal is produced by the reduction of resazurin to resorufim intracellularly by mitochondrial enzyme activity based on their cellular metabolic activity and can be detected by a microplate reader (Infinite 200, Tecan, Hammedorf, Germany). The Alamar blue assay was used at day 1, 3, 7 and 14.
Wound healing and antibacterial capability of electrospun polyurethane nanofibers incorporating Calendula officinalis and Propolis extracts
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Masoud Davoudabadi, Shoreh Fahimirad, Ali Ganji, Hamid Abtahi
Broth microdilution method was used to evaluated the minimum inhibiting concentration of C. officinalis and Propolis extracts against S. aureus CHA (NCTC No. 10442) bacteria. The strain was grown in MHB media adjusted to 106 colony-forming units (CFU/mL). Afterward, 50 µl of MHB was poured into each row of 96-well microplates. Then, 50 µl of C. officinalis and Propolis extract (dissolved in DMSO) was added to the first row and serially diluted from the first to the last well. The positive growth control was 100 µl of bacterial inoculum without any treatment in row 11, and the rows containing 100 µl of MHB were considered the sterility control. Each row, except the sterility control, was inoculated with 50 µl of the bacterial suspension. After 24 h of incubation, to check the antibacterial effect of the extracts, resazurin reagent was used; in this way, resazurin reagent was added to all the wells, and after 20 min of incubation, the last blue well illustrated the minimum concentration of substance inhibited bacterial growth and considered as MIC. Resazurin assay is a colorimetric indicator used to monitor the presence of metabolically active cells. Aerobic respiration metabolic products of live cells convert blue- colored resazurin to pink-colored resorufin product [22,23].
Toxicological, chemopreventive, and cytotoxic potentialities of rare vegetal species and supporting findings for the Brazilian Unified Health System (SUS)
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Jurandy do Nascimento Silva, Nayana Bruna Nery Monção, Ruth Raquel Soares de Farias, Antonia Maria das Graças Lopes Citó, Mariana Helena Chaves, Mônica Regina Silva de Araújo, Daisy Jereissati Barbosa Lima, Claudia Pessoa, Alessandro de Lima, Edigênia Cavalcante da Cruz Araújo, Gardenia Carmen Gadelha Militão, Marcília Pinheiro da Costa, Raffaele Capasso, Paulo Michel Pinheiro Ferreira
Cytotoxic methods revolutionized cell-based drug screening by offering a high-throughput screening colorimetric assay. These techniques simplified sample processing which requires no radioisotope but are sufficiently sensitive for miniaturization into 96-well plate formats, as seen in MTT, ATP, and Alamar BlueTM assays. These methods were used in the search for new substances with antiproliferative activity and toxic potential (Ferreira et al. 2016; Mosmann 1983; Rampersad 2012; Silva et al. 2019; Skehan et al. 1990). Both MTT and Alamar Blue methods incorporate a colorimetric growth indicator based upon detection of mitochondrial metabolic activity during oxidation-reduction events in response to chemical reduction of growth medium resulting from cell growth. These are commonly employed for similar purposes. Resazurin is more sensitive to detect oxidation-reduction events from lower number of viable cells, which saves time and money (Rampersad 2012).
Exploring the therapeutic potentials of phyto-mediated silver nanoparticles formed via Calotropis procera (Ait.) R. Br. root extract
Published in Journal of Experimental Nanoscience, 2020
Suresh Sagadevan, Selvaraj Vennila, Lakshmipathy Muthukrishnan, K. Gurunathan, Won Chun Oh, Suriati Paiman, Faruq Mohammad, Hamad A. Al-Lohedan, Ainil Hawa Jasni, Is Fatimah, Kuppan Sivaranjan, Prasanna Kumar Obulapuram
Prior to the preliminary antibacterial screening of AgNPs using agar diffusion test, MIC and MBC were performed to validate the antibacterial potential. The recorded MIC values at which no visible growth of test bacterial strains is found are presented in Table 3. This range of concentration was selected prior to an initial antimicrobial screening where the inhibitory phenomenon was most prominent. The antimicrobial effect for AgNPs towards a panel of clinical isolates was appreciated by the amount of fluorescent Resorufin produced in proportion to the viable bacterial cell concentrations. Resazurin (7-hydroxy-3H-phenoxazin-3-one 10-oxide) is a blue dye that gets irreversibly reduced to Resorufin producing pink fluorescence by the action of oxidoreductases indicative of viable cells. However, in the non-viable cells, this Resorufin is further reduced to a colourless and a non-fluorescent molecule, hydroresorufin [29]. Among the tested pathogens, S. flexneri, E. coli, P. aeruginosa and E. faecalis were found more sensitive to AgNPs with a MIC value of 3.12 μg/mL followed by S. typhi and B. subtilis with an MIC value of 6.25 μg/mL. Whilst S. aureus, Enterococcus sp., K. pneumoniae and S. epidermidis were found resistant to AgNPs among the tested strains showing a MIC value of 12.5 μg/mL. This difference in MIC values could have resulted due to differences in their metabolic activity. In addition, the tendency of bacteria to form films might limit the accessibility of fluorophores to bacteria within the biofilm preventing the emission of fluorescence signal [30].