Nanocapsules with excellent biocompatibility and stability in protein solutions

2021 ◽  
Author(s):  
Arjaree Jobdeedamrong ◽  
Man Theerasilp ◽  
Norased Nasongkla ◽  
Daniel Crespy
Keyword(s):  
Cationic Surfactants ◽  
Protein Solutions ◽  
The Stability ◽  
Silica Nanocapsules

Silica nanocapsules (SiO2NCs) are usually prepared with cationic surfactants that are not cytocompatible. Dialysis can remove the surfactant but imparts detrimentally the stability of the SiO2NCs in the presence of...

The crystallography of calf rennin (chymosin)

1971 ◽  
Vol 178 (1052) ◽  
pp. 245-258 ◽  
Keyword(s):  
Degradation Products ◽  
Protein Solutions ◽  
Stable Range ◽  
X Ray Diffraction ◽  
Stable Species ◽  
Wide Range ◽  
Unit Cells ◽  
Diffraction Patterns ◽  
The Stability ◽  
Ph Range

The growth of crystals of calf rennin (chymosin, † EC 3.4.4.3) and the control of nucleation to produce crystals of desired size, are described. Only one stable species, orthorhombic rennin I, has been found, but a metastable monoclinic species, rennin II, appeared on one occasion in a solution nearly saturated with glycine. The morphology, optical characteristics and unit cells of these species are recorded. In rennin I, small differences in the properties of sectors built by deposition on the three types of crystal faces are attributed to differences in the proportions of either degradation products or of the slightly different isoenzymes known to be present in calf rennin. Rennin I crystals have been obtained only within the pH range of greatest stability of the protein, 5. 0 to 6. 2; but the crystals tolerate subsequent changes of pH down to 2. 0. The stability of crystals appears to be much greater than that of salt-free protein solutions. Rennin I may be crosslinked with glutaraldehyde with no loss of order, giving crystals stable over a wide range of solution conditions, including pH 2.0 to 10.0 and salt-free solutions. The remarkable swelling behaviour when the pH is raised beyond the stable range is described. Rennin II, though monoclinic in symmetry, shows in its X -ray diffraction patterns strong evidence of a pseudo-orthorhombic arrangement of molecules.

Nanoarchitectonics of Photoluminescent InP/ZnS Quantum Dots Encapsulated Silica Capsules in Physiological Solutions

2020 ◽  
Vol 20 (5) ◽  
pp. 2722-2727
Author(s):  
Chunliang Li ◽  
Norio Murase ◽  
Wei Li
Keyword(s):  
Aqueous Solution ◽  
Cell Culture ◽  
Quantum Dots ◽  
Culture Medium ◽  
Carboxyl Group ◽  
Cell Culture Medium ◽  
Typical Cell ◽  
The Stability ◽  
Silica Nanocapsules ◽  
Photoluminescence Efficiency

Optical properties and morphology of silica nanocapsules (ca. 40 nm of size) incorporated with multiple InP/ZnS quantum dots (QDs, ca. 3.5 nm of size) have been investigated systematically in a typical cell culture medium (Dulbecco Modified Eagle Medium, DMEM buffer) over a period of time. The stability of silica nanocapsules with multiple QDs are found to be more robust, compared to the original aqueous pristine QDs over a period of 6 h. However, their photoluminescence efficiency is decreased after 8 h, accompanied by a change in morphology of the silica capsules. This change in morphology is caused by the dissolution of silica by alkali, and alkali-earth cations in the buffer. Our results confirm that the silica nanocapsule surface modification occurs in aqueous solution, resulting in a change from hydroxyl to carboxyl group. We also discuss possible methods to further increase the stability of the silica nanocapsules in physiological solutions.

scholarly journals Antimicrobial Activities of Hydrophobically Modified Poly(Acrylate) Films and Their Complexes with Different Chain Length Cationic Surfactants

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 244
Author(s):  
Ioana Cătălina Gîfu ◽  
Monica Elisabeta Maxim ◽  
Ludmila Otilia Cinteza ◽  
Marcela Popa ◽  
Ludmila Aricov ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Cationic Surfactants ◽  
Antimicrobial Properties ◽  
Multilayer Films ◽  
Antimicrobial Activities ◽  
Layer By Layer ◽  
Antimicrobial Efficiency ◽  
Hydrophobically Modified ◽  
Multilayered Systems ◽  
The Stability

Multilayer films from hydrophobically modified poly(acrylic acid) (HMPA) and their complexes with cationic surfactants were successfully prepared using the layer-by-layer (LbL) method. Alkyl trimethylammonium bromide derivatives with various lengths of the hydrophobic chain (C10–C18) were used to interact with the HMPA polymer, generating highly hydrophobic domains in the films and contributing to the antimicrobial properties of the prepared coating. The antimicrobial efficiency against common pathogens such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans was investigated in relationship with the morphology and composition of the thin films. The wettability and roughness of the multilayered systems were evaluated using atomic force microscopy (AFM) and contact angle measurements. The effects of the microbial exposure on the surface properties of the prepared films were investigated in order to assess the stability of the HMPA-deposited multilayers and the durability of the antimicrobial activity. The hydrophobically modified films exhibited antimicrobial activity against the studied pathogens. The best efficiency was registered in the case of S. aureus, which showed an inhibition of growth up to 100% after 2 h. C. albicans proved to be less sensitive to the effect of the multilayers deposited from HMPA–surfactant complexes. These results suggest that HMPA and HMPA–surfactant complex LbL multilayer films can be used as promising materials in antimicrobial surface coatings with increased resistance to pathogens during exposure.

Thermodynamics of the micellization of quaternary based cationic surfactants in triethanolamine-water media: a conductometry study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Medinat O. Osundiya ◽  
Segun E. Olaseni ◽  
Rasaq A. Olowu ◽  
Olanrewaju Owoyomi
Keyword(s):  
Free Energy ◽  
Cationic Surfactants ◽  
Mixed Micelles ◽  
Elevated Temperatures ◽  
Electrical Conductance ◽  
Hexadecyltrimethylammonium Bromide ◽  
Conductance Method ◽  
Water Media ◽  
The Stability ◽  
Free Energy Of Micellization

Abstract The effect of triethanolamine, a solvent with wide technical and industrial benefit on the micellization of an aqueous mixture of cationic surfactants, dodecyltrimethylammonium bromide (DETAB) and hexadecyltrimethylammonium bromide (HATAB) was studied to examining the stability of the mixed micelles at 298.1, 303.1, 308.1 and 313.1 K using the electrical conductance method. The values of the critical micelle concentration (C*) were found to decrease with an increase in the concentration of triethanolamine (TEA). The values of the free energy of micellization (ΔGm) were negative at a particular temperature, and the extent of spontaneity was discovered to increase when the concentration of TEA was increased. However, an increase in temperature was observed to have a negative linear relationship with the spontaneity of the process. The formation of the mixed micelles was an exothermic process, and it was also TEA and temperature-dependent with a trend similar to those observed in the free energy of micellization (ΔGm). The degree of disorderliness of the system was also found to be entropy driven at a higher concentration of TEA. The synergistic interaction between the molecules of DETAB–HATAB in the presence of TEA (0.4% v/v) and the spontaneity of the system was at the maximum at 0.1:0.9 mol fraction ratio and the energetics of the system was discussed based on hydrophobic–solvophobic interaction of the monomers in TEA at elevated temperatures.

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