Properties Of Different Preparations Research Articles

Adjusting Paper Device Properties for Bioelectrochemical Analysis and 3D Cell Culture

Context- Paper is an innovative material for cell culture due to its biocompatibility, its inert chemical properties and its low-cost. Paper is already used in many biomedical applications such as immunoassays and, more recently, as affordable electrochemical sensors. In this context, tuning the properties of paper devices can achieve better, more efficient and user-friendly assays for biomedical applications. Here, and by modifying the electrochemical properties of paper electrochemical devices, it is possible to create electrodes that can detect neurotransmitters, a critical type of biomolecules involved in neuronal communication. Dopamine is a neurotransmitter involved in reward and addiction and a molecule of considerable scientific interest. Dopamine is secreted in the brain by dopaminergic neurons. However, the fine chemical mechanisms of neuron networks are still obscure. Being able to spatially measure dopamine secretion, in response to activation of precise neuronal regions in a unique system, can lead to a better understanding of neuronal dynamics, as well as their response to drug alterations. Proposing a research model describing neuronal chemical function in a network will therefore help shining light on their mechanisms and testing new neuropharmacological solutions. Developing new tools for the analytical electrochemistry of the brain will make quantitative neuro-analysis more accessible, thus paving the way for a better understanding of the chemical mechanisms of the brain. Tuning paper electrode for neurochemical analysis- Conductive inks, i.e. conductive polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) and carbon nanotubes (CNT) suspensions, were used to improve the detection of dopamine at paper-based electrodes. The physical and chemical properties of different preparations and mixtures of inks were considered. Solvent secondary doping, a common technique for PEDOT-PSS based electrode, was used to improve the electrical properties of the electrodes. Ferrocyanide electroanalysis was used to benchmark 10 different electrode preparations, revealing that combining CNT and PEDOT-PSS improves the electroactivity of the surface of the sensor. Interestingly, it was found that CNT has a doping effect on PEDOT-PSS, leading to improved electrochemical properties. Finally, these electrodes were tested for dopamine detection. It was found that combining PEDOT-PSS and CNT in the surface layer of ink deposited on the paper electrode allows for lower capacitance, higher anodic current as well as better fouling resistance. Figure 1 presents a CV voltammogram for Dopamine obtained with a paper electrode. Overall, this strategy improves the sensitivity of the assay. Growing neurons on paper- Paper-based devices can also be used for cell culture. Cell on paper constructs are 3D cell culture models that are more suitable to study cell in a biomimetic 3D environment, thus better recapitulating their functions and biology. By carefully modifying the surface of the paper devices, it is possible to adjust their biocompatible properties to ameliorate the survival rate of cell culture on paper. This opens the possibility to achieve neuronal cell culture on paper. We will present different paper preparations compatible with murine dopaminergic maintenance. The neurons were maintained alive for several days of culture. We were able to effectively observe and study neurons in a 3D paper environment and quantify the growth of their processes. Figure 1 : Electrochemical detection of Dopamine for 20 cycles. Working electrode is a paper electrode with PEDOT:PSS and CNT conductive inks, shown on the right, scale is 1 cm. The reference electrode is an Ag/AgCl electrode, and the counter electrode is a platinum electrode. Scan rate is 0.02 Vs-1. Figure 1

The probiotic properties of different preparations using Lactococcus lactis Z-2 on intestinal tract, blood and hepatopancreas in Cyprinus carpio

Basing on the beneficial effects of live Lactococcus lactis Z-2 and its extracellular polysaccharides on the common carp (Cyprinus carpio L.) in the previous studies, the present study aims may be appropriate to investigate the functions of other forms of L. lactis Z-2 (namely, heat-killed or cellular components) on the intestinal tract, blood and hepatopancreas of common carp. 480 fish [(42.35 ± 0.76) g] were treated with different preparations of L. lactis Z-2 for 7 days and infected with Aeromonas hydrophila for 24 h, following which to detect the levels of NO and cytokines, the activities of lysozyme (LZM) and alkaline phosphatase (AKP) in the serum, the antioxidants (T-AOC, SOD, CAT, GSH, GSH-Px and MDA) in hepatopancreas, the digestive enzymes and the gene expression of nutrient transporters in intestinal. Prior to infection, different treatment groups significantly enhanced NO production, the levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), AKP activity, antioxidant content (T-AOC, SOD, CAT, and GSH), and reduced MDA level compared to those in the negative control group (P < .05). In addition, the activities of LZM in the serum and GSH-Px in the hepatopancreas were significantly promoted in most groups (P < .05). Furthermore, different treatment groups significantly increased the activities of digestive enzymes (amylase, lipase and protease), and the genes expression of nutrient transporters (Sglt1, Glut2, Pept1, rBAT, except HK treatment group). While, the levels of NO and pro-inflammatory cytokines in the treatment groups were significantly lower than those in the positive control group after infection (P < .05), but remained relatively stable. Although the LZM and AKP activities decreased significantly upon A. hydrophila infection, the treatment groups still significantly enhanced the LZM and AKP activities (P < .05). In addition, the antioxidant capacity significantly increased in the treatment groups after infection. However, regardless of the infection status, the expression levels of anti-inflammatory cytokines (IL-10, TGF-β) increased significantly in the treatment groups (P < .05). Therefore, these results suggested that the different preparations of L. lactis Z-2 exerted immunomodulatory and antioxidant effects, disease resistance, and promoted nutrient metabolism in common carp; this can form the theoretical basis for the rational use of potential probiotics and provide new perspective in the use of lactic acid bacteria in microecological preparations.

The reactivity of well-dispersed zerovalent iron nanoparticles toward pentachlorophenol in water

In order to prevent the aggregation of nanoparticles (NPs), surface modification or the addition of a stabilizer are used for stabilization. However, the real reactivity of NPs is still unclear because of the surface coating. For different physical dispersion methods, the particle stabilization for nanoscale zerovalent iron (NZVI) particles and their reactivity are studied. The particle properties of different preparations and their reactivity toward one polychlorinated aromatic compound, pentachlorophenol (PCP), with different electrolytes are also evaluated. Ultrasonication (US) with magnetic stirring disperses NZVI and Pd/Fe NPs well in water and does not affect the surface redox property a lot under the operating conditions in this study. The well-suspended NZVI cannot dechlorinate PCP but adsorption removal is observed. Compared to shaking, which gives limited removal of PCP (about 43%), Pd/Fe NPs remove 81% and 93% of PCP from water in the US and the US/stirring systems, respectively, which demonstrates that a greater surface area is exposed because of effective dispersion of Pd/Fe NPs. As the Pd doping increases, the dechlorination kinetics of PCP is improved, which shows that a catalyst is needed. With US/stirring, chloride ions do not significantly affect the removal kinetics of PCP, but the removal efficiency increases in the presence of nitrate ions because PCP anions were adsorbed and coagulated by the greater amount of iron (hydro)oxides that are generated from the reduction of nitrate on Pd/Fe. However, bicarbonate ions significantly block the adsorption and reaction sites on the Pd/Fe NP surface with US/stirring. The US/stirring method can be used to evaluate the actual activity of NPs near the nanoscale. The use of Pd/Fe NPs with US/stirring removes PCP from water effectively, even in the presence of common anions expect a high concentration of bicarbonate.

Sodium caseinates — composition and properties of different preparations

A number of samples of commercially available spray‐dried and roller‐dried caseinates have been compared with freshly prepared caseinate from the laboratory. The compositions of the materials were measured using chromatography, and their calcium susceptibilities were determined using turbidity measurements. The chromatographic analysis showed that the commercial caseinates differed substantially from the fresh material, especially in the regions where α‐casein and αs2‐caseins were eluted. The fresh caseinate was more affected by the presence of calcium ions than the others, and there were also differences between the individual spray‐dried caseinates in this respect. The roller‐dried caseinates were very insensitive to the presence of calcium ions.

Variability in the catalytic and allosteric properties of rabbit liver fructose 1,6-diphosphatase: The presence of tryptophan in homogeneous enzyme

Rabbit liver fructose 1,6-diphosphatase purified to homogeneity by the procedure of Sarngadharan et al. (1) has been found to contain tryptophan. The basis for variability in tryptophan content and catalytic and regulatory properties of different preparations of the enzyme is discussed. Variable proteolysis during isolation is presumed to be the major factor.

Enzymic assay for galactosyl transferase activity of lactose synthetase and α-lactalbumin in purified and crude systems

The enzymic assay for the A protein of lactose synthetase (galactosyl transferase) was carefully evaluated using bovine α-lactalbumin to assay for purified bovine A protein and the A protein in rat mammary homogenates. With purified bovine proteins, the maximum activity was found with 200 μg α-LA/ml with higher levels being inhibitory. With the rat A protein in mammary homogenates, 1 mg bovine α-LA/ml gave the maximum rate. The assay parameters for maximum lactose synthetase and N-acetyllactosamine formation were similar. The enzymic assay for the B protein (α-lactalbumin) of lactose synthetase has been thoroughly investigated using purified bovine α-LA and α-LA present in rat mammary gland homogenates. A correction was necessary for the endogenous lactose synthetase activity of the A protein alone which was dependent on the glucose concentration in the assay. A standard curve of bovine α-LA was necessary for each set of assays since there was variation in the properties of different preparations of the A protein. Under the assay conditions described the amount of α-lactalbumin in the assay (0.02–1.0 μg) per milliliter was quantitatively related to the amount of standard bovine α-lactalbumin.