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The Polymeric Matrix and its Influence
Published in Maik W. Jornitz, Theodore H. Meltzer, Sterile Filtration, 2020
Maik W. Jornitz, Theodore H. Meltzer
The performance of various polymer type membranes in 10 in. cartridge form in the retention of protein was investigated by Datar et al. (1992). The use of cartridge filters instead of flat membrane disks (13 or 47 mm) enabled the assessment of the influence of the conventional support and drainage layer construction on the protein retention. The effect of prefilters could also be measured. BSA in 90 μg/mL concentration was the protein used. The polymer types examined were hydroxyl-modified polyamide and hydrophilic PVDF. Neither showed any diminution of concentration in the effluent. Polysulfone and cellulose acetate cartridges were also tested. The latter showed protein loss throughout the filtration. This, it is hypothesized, was due to surfactant that was presumed to have been added to the polymer for wettability. The polysulfone cartridge evinced a slight drop in effluent concentration over the course of the filtration. Interestingly, the use of polypropylene prefilters did not lead to the significant loss of protein that could have been expected from that polymer’s hydrophobicity. When a cellulose acetate prefilter was used, considerable protein loss was sustained. This too is unexpected. Demonstrated is the need to consider the adsorptive capacity of the entire filtration train, not just the final filter.
DNA-Functionalized Gold Nanoparticles
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
At the first glance, it is difficult to understand the internalization of negatively-charged DNA/AuNP complex by cells. To determine the cause of this, the size and zeta potential of the DNA-functionalized AuNP were measured before and after cell uptake (Giljohann et al. 2007). An increase in particle size and a rise in zeta-potential were measured, suggesting the adsorption of extracellular proteins by the DNA strands. Further research has revealed the specific proteins that might mediate cellular uptake of DNA-functionalized AuNPs (Patel et al. 2010). Serum generally contains a wide range of proteins such as bovine serum albumin (BSA), which is traditionally used as a blocking agent for protein adsorption and is found in great abundance in serum. The adsorption of BSA onto the surface of a DNA-functionalized AuNP was demonstrated to be non-effective in aiding cellular internalization. Increased cell uptake is accomplished by the displacement of these serum proteins by scavenger receptors, which then act as mediators for endocytosis of the DNA-functionalized AuNPs (Figure 10.9a).
Integrated Cantilever-Based Biosensors for the Detection of Chemical and Biological Entities
Published in Tuan Vo-Dinh, Nanotechnology in Biology and Medicine, 2017
Elise A. Corbin, Ashkan YekrangSafakar, Olaoluwa Adeniba, Amit Gupta, Kidong Park, Rashid Bashir
The mass of the antibody and BSA layer that was adsorbed on the cantilever beam surface was measured to be around 90 pg. In order to estimate whether the values were reasonable, one can make some rough calculations. The molecular weight of an antibody molecule (IgG) is estimated to be around 150 kDa, with an effective area for a single molecule to be around 45 nm2. The molecular weight of a BSA molecule is around 66 kDa with an effective area of around 44 nm2 (assuming BSA to be an ellipsoid with dimensions of 14 nm by 4 nm). Since the antibody was first attached to the cantilever beam, followed by BSA, it is safe to assume that the BSA covers only those area not covered by the antibody itself and that they do not attach to the antibody layer. It should be reasonable to assume that the antibodies cover the majority of the surface area of the cantilever beam. Assuming total coverage over the entire cantilever surface area (top and bottom of the cantilever) by the antibody, a mass of around 87 pg (mass of antibody layer divided by 0.24) is calculated. Since the antibodies and BSA are nonspecifically adsorbed, they will be randomly attached to the cantilever and could also be attached in multiple layers. The measured values of added mass are, however, in the expected pg range.
Exploring the binding mechanism of Ginsenoside Rd to Bovine Serum Albumin: Experimental studies and computational simulations
Published in Journal of Dispersion Science and Technology, 2022
Jialiang Lin, Min Tang, Manjunath D. Meti, Yong Liu, Qingguo Han, Xu Xu, Yuan Zheng, Zhendan He, Zhangli Hu, Hong Xu
It has been known that BSA is a globular protein and composed of 583 amino acids with molecular weight of 66 kDa.[8,9] It consists of three homologous domains (I-III), and each domain includes two subdomains (A and B).[6] The two hydrophobic pockets on BSA are named as sites I and II, and located in subdomains IIA and IIIA, respectively,[10] and the major two tryptophan (Trp) residues (Trp 134 and Trp 213) are located in subdomains IA and IIA, respectively, as shown in Figure 1a.[11] In addition, Trp 134 residue is on the surface, while Trp 213 residue locates in the hydrophobic pocket.[12,13]
Effect of size and surface chemistry of gold nanoparticles on their retention in a sediment-water system and Lumbriculus variegatus
Published in Journal of Environmental Science and Health, Part A, 2021
Ping Luo, Guibin Ma, Agnieszka Dudkiewicz, Zhen Mao, Lizhang Wang, Jiachao Jiang
This study explored how different physiochemical properties of AuENPs influenced their aggregation/agglomeration and sedimentation in a sediment-water system and affected their retention/uptake by L. variegatus. L. variegatus is a freshwater sediment-dwelling worm used in regulatory toxicity testing (OECD 2012) and in its natural environment may be exposed to contaminants both across the skin and through ingestion. Selected AuENPs were coated with either citrate (CIT), 11-mercaptoundecanoic acid (MUDA) or bovine serum albumin (BSA) with a nominal size of 5 or 30 nm. BSA is a large protein molecule with hundreds of amino groups (MW ≃ 55,000). CIT is a weak, short-chain organic acid (C6H8O7, MW = 192) with three carboxylate groups. MUDA (C11H22O2S, MW = 218) has a thiol group, a long chain and one carboxylate group. The AuENPs were well characterized since the same batch had been previously studied for the effects of particle size and coating on their environmental fate.[16,23,24,26–28] Therefore, this study mainly focused on how different physiochemical properties of AuENPs affected their retention/uptake by L. variegatus.
Identification of Phytoplankton from Fresh Water and Growth Optimization in Potent Algae by Response Surface Methodology for Enhanced Biomass Production
Published in Smart Science, 2020
Santhosh Sigamani, Mohammed Habeeb Ahmed, Hemalatha Natarajan, Dhandapani Ramamurthy
To 50 ml of 2.0 % sodium carbonate 50 ml of 0.1 N sodium hydroxide was added which is Solution a, 10 ml of 1.5 % CuSO4 solution was added to 10 ml of 2.3 % tartarate solution regarded as Solution b. The reagent was mixed by adding 2.0 ml of solution b with 100 ml of solution a. A freshly prepared folin-ciocalteau reagent solution was prepared by adding double the volume of water (2:1) ratio. Different dilutions of BSA were prepared by mixing stock BSA solution (1.0 mg/ml) and water in the test tube. The BSA was prepared at various concentrations ranging from 0.05 to 1.0 mg/ml. From these dilutions, 0.2 ml of protein solution was added to different test tubes and 2.0 ml of alkaline copper sulfate reagent was added (analytical reagent) and mixed well. This solution was incubated at room temperature for 10 mins. Upon incubation 0.2 ml of folin’s phenol reagent was added to each tube, agitated and incubated for 30 min. The spectrophotometer was set to auto zero with blank and optical density (OD) was measured at 660 nm. The standard calibration curve was plotted for protein concentration and OD value of unknown samples was recorded [18].