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Electrochemical Surface Plasmon Resonance and Its Applications in Biosensing, Bioelectronics, and Material Science
Published in Volodymyr I. Chegel, Andrii M. Lopatynskyi, Molecular Plasmonics, 2020
Volodymyr I. Chegel, Andrii M. Lopatynskyi
As objects for research, an enzyme trypsin (molecular weight about 23–24 kDa, isoelectric point pI = 10.1–10.8) and its inhibitor, obtained from soybeans (STI, molecular weight about 20–21 kDa, isoelectric point pI = 4.5) were selected. For the preparation of protein solutions, phosphate-buffered saline (PBS) solution, widely used in biochemicalstudies, was used. The measured pH value of the PBS buffer solution at 25°C was 7.25. Thus, dissolution of trypsin molecules in the used buffer solution leads to their positive total charge, since the isoelectric point of trypsin lies higher than the pH of PBS [32]. For STI molecules, the situation is opposite; when dissolved in PBS, they get a total negative charge. That is, the behavior of these biomolecules when located in the same electrical fields should be different.
Investigation and Application of HA Composite Coating on the Ti Alloy
Published in Sam Zhang, Hydroxyapatite Coatings for Biomedical Applications, 2013
Wei Qiang, Zhao Jin, Zhang Lijun, Liu Shimin, Liang Yanqin
After cleaning the samples with agent and ethanol, they were exposed to phosphate-buffered saline (PBS) to deposit HA. PBS is a solution with pH and ion concentrations similar to those of human blood plasma. HA coating had formed on the rutile surface after immersion for 7 days (see Figures 8.19 and 8.20). When the rutile surface is exposed to body fluids, OH groups adsorb to the titanium ions in the oxide and negative Ti–O groups are formed over it. These negative sites attract Ca2+ ions from the body fluid. A layer of amorphous calcium titanate is formed, and the surface becomes slightly positively charged. It will then attract negatively charged phosphate ions and calcium phosphate is formed. This layer is then crystallized into bone-like apatite because it is thermodynamically more favorable in a wet environment [16].
Hydrogel-Based Composites in Perfusion Cell Culture/Test Device
Published in S. M. Sapuan, Y. Nukman, N. A. Abu Osman, R. A. Ilyas, Composites in Biomedical Applications, 2020
When a swollen hydrogel sinks into buffer solution, the exchange of molecules between the hydrogel and its external environments starts immediately. In this study, the cylindrical PHEMA-CNT composite sample, which is fully swollen by glucose solution (200 g/L), is placed into PBS buffer (phosphate buffered saline) to investigate the kinetics of diffusion of the PHEMA-CNT composite to glucose, including diffusion speed, diffusion mechanism, and capacity of absorption. PBS buffer is a commonly used buffer solution in biological research, which can mimic the environment of inside the human body, because the pH value, osmolarity, and ion concentrations of PBS buffer are identical to the isotonic environment of the human body.
Preparation and characterization of human scar acellular dermal matrix
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Chenzhi Lai, Guodong Song, Bo Zhao, Hongquan Wang, Bo Pan, Xiaoshuang Guo, Xiaolei Jin, Xianlei Zong
All epidermal and fat tissues were separated. The harvested dermis was cut into approximately 0.5-mm-thick sections using a free-hand graft knife and placed in 1% peracetic acid and 24% absolute ethyl alcohol for 2 h. Whole sterilized materials were immediately placed in sterile PBS and processed for 30 min for subsequent harvesting, twice for each specimen. Next, tissues were washed three times with purified water for 10 min per specimen. The remaining material was digested with 2.5 g/L trypsin and 0.5 mM Na-ethylenediaminetetraacetic acid for 2 h under constant agitation. The specimens were digested with 1% Triton X-100 solution at 37 °C under constant agitation for 72 h. During agitation, Triton X-100 solution was replaced once every 24 h. The remaining material was washed twice with PBS for 30 min each and three times with purified water for 10 min. Finally, the test materials were placed in 0.9% NaCl supplemented with 100 IU/mL penicillin and stored at 4 °C.
Preparation and drug release application of pH and light dual-stimuli- responsive nanocarrier based on mesoporous silica nanoparticles
Published in Journal of Dispersion Science and Technology, 2019
Si Chen, Jin Hu, Feng Wang, Hui Liu
The release of DOX from MSNs@DOX initiated by physiological stimuli was investigated under different conditions: (i) PBS (0.1 M, pH 7.4), (ii) hydrochloric acid solution (pH 3.0), (iii) UV light at 365 nm, PBS (0.1 M, pH 7.4), (iv) UV light at 365 nm, hydrochloric acid solution (pH 3.0).
Generation, characterization, and comparison of human exhaled and technical aerosols for the evaluation of different air-purifying technologies against infectious aerosols
Published in Journal of Occupational and Environmental Hygiene, 2022
Thomas Penner, Simon Berger, Jennifer Niessner, Achim Dittler
The selection of the nebulized liquids and the nebulizers used was based on the respective applications as test aerosols for various cases, which included testing filtrating and inactivating air purifiers. On the one hand, aerosols were generated from saline solutions of various concentrations. The generation of such salt aerosols has already been extensively tested in the context of various other works, among others for the characterization of room air cleaners (Tobisch et al. 2021; Szabadi et al. 2022). A major advantage of aerosol generation from salt solutions is that essential aerosol characteristics can be changed via the salt concentration. When the water is removed from the generated solution droplets in the drying section, a salt core remains which may be significantly smaller than the originally generated particles. The size of these dried salt particles depends largely on the original droplet size, as well as the salt content of the droplet i.e., the salt concentration of the solution. Solutions with mass concentrations of 4, 10, and 16.6% NaCl were nebulized. Furthermore, a saliva substitute solution (apomix saliva substitute solution SR, Pharmazeutische Kontroll- und Herstellungslabor GmbH, Germany) was atomized to simulate aerosols from human saliva. This mainly contained carmellose, sorbitol, and various salts. However, it could not be ascertained whether this solution actually corresponded to human saliva in terms of its physical properties. This is complicated by the fact, that composition and thus properties of human saliva show great inter- and interindividual differences (Humphrey and Williamson 2001). Due to the adjustability of the particle size and suitability as test aerosols for air purifiers according to VDI-EE 4300 Blatt 14, liposomes were also used as test particles. For this purpose, a suspension containing liposomes was used. Liposome suspension was provided by Fraunhofer IMM with a stock solution of 32 g/L of phospholipides in deionized water as the dispersion medium. Characterization of liposomes yielded an average particle size of 83.4 nm and narrow size distribution (standard deviation of 19.8 nm). The average size was determined by dynamic light scattering (DLS) using a NANO-flex system (Microtrac Europe GmbH, Germany) which operates at a measuring angle of 180°. For experiments using (surrogate) viruses, a phosphate-buffered salt solution (PBS) was atomized and the resulting aerosol was characterized. The PBS is an isotonic salt solution, with NaCl, KCl, and several phosphates as components. Nebulized liquids used in this study with their respective contents and concentration of particle material are listed in Table 2.