sodium-dodecyl-sulfate and ammonium-peroxydisulfate

A colorimetric assay for acid phosphatase (ACP) was constructed that is based on in situ polymerization of aniline catalyzed by gold nanoparticles (AuNPs). Aniline can be polymerized by ammonium persulfate (APS) in acidic condition and form gold-polyaniline core-shell nanoparticles (Au@PANI NPs) in the presence of AuNPs with the assistance of sodium dodecyl sulfate (SDS). AuNPs were also found to accelerate the polymerization process of aniline and thus shorten the reaction time. Upon the introduction of ascorbic acid (AA), the oxidant APS was consumed via the redox reaction. That led to the suppression of the formation of PANI. Consequently, ACP activity can be supervised on the basis of hydrolysis of 2-phospho-L-ascorbic acid trisodium salt (AAP) catalyzed by ACP to release AA. With the increase of ACP activity, the intensity ratio of the absorbance at λ

Topics: Acid Phosphatase; Ammonium Sulfate; Aniline Compounds; Catalysis; Colorimetry; Gold; Humans; Limit of Detection; Metal Nanoparticles; Polymerization; Sodium Dodecyl Sulfate

Microgels are colloidally stable, hydrogel microparticles that have previously been used in a range of (soft) material applications due to their tunable mechanical and chemical properties. Most commonly, thermo and pH-responsive poly(N-isopropylacrylamide) (pNIPAm) microgels can be fabricated by precipitation polymerization in the presence of the co-monomer acrylic acid (AAc). Traditionally pNIPAm microgels are synthesized in the presence of a crosslinking agent, such as N,N'-methylenebisacrylamide (BIS), however, microgels can also be synthesized under 'crosslinker free' conditions. The resulting particles have extremely low (<0.5%), core-localized crosslinking resulting from rare chain transfer reactions. AFM nanoindentation of these ultralow crosslinked (ULC) particles indicate that they are soft relative to crosslinked microgels, with a Young's modulus of ∼10 kPa. Furthermore, ULC microgels are highly deformable as indicated by a high degree of spreading on glass surfaces and the ability to translocate through nanopores significantly smaller than the hydrodynamic diameter of the particles. The size and charge of ULCs can be easily modulated by altering reaction conditions, such as temperature, monomer, surfactant and initiator concentrations, and through the addition of co-monomers. Microgels based on the widely utilized, biocompatible polymer polyethylene glycol (PEG) can also be synthesized under crosslinker free conditions. Due to their softness and deformability, ULC microgels are a unique base material for a wide variety of biomedical applications including biomaterials for drug delivery and regenerative medicine.

Topics: Acrylamides; Acrylates; Acrylic Resins; Ammonium Sulfate; Cross-Linking Reagents; Hydrogels; Isocyanates; Polyethylene Glycols; Rheology; Silanes; Sodium Dodecyl Sulfate

Studies on Salmonella typhi and Salmonella typhimurium outer membrane proteins have shown that the relative position of OmpC porin in sodium dodecyl sulfate.polyacrylamide gel electrophoresis undergoes an important shift when the concentration of ammonium persulfate in the running gel is increased from 6 to 12 mM. The apparent molecular mass at these concentrations was estimated to be 34 and 40 kDa, respectively. Under similar electrophoretic conditions the apparent molecular mass estimated for OmpF was 37.6 and 38.2 kDa. Therefore, OmpC moves from a leading position to a position behind OmpF. For Escherichia coli OmpC the shift observed is less pronounced than that occurring in Salmonellae.

Topics: Ammonium Sulfate; Bacterial Outer Membrane Proteins; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Molecular Weight; Porins; Salmonella typhi; Salmonella typhimurium; Sodium Dodecyl Sulfate