Acetylcholinesterase immobilized onto PEI-coated silica nanoparticles

Abstract

Polyethyleneimine (PEI) coated-silica nanoparticles were prepared by the Stöber method. The formation and the structure of the nanoparticles were characterized by ATR-FT-IR spectroscopy and transmission electron microscopy (TEM). TEM images of the silica and PEI-coated nanoparticles revealed that they were well dispersed and that there was no agglomeration. The acetylcholineesterase enzyme was immobilized onto these nanoparticles. The effects of pH and temperature on the storage stability of the free and immobilized enzyme were investigated. The optimum pHs for free and immobilized enzymes were determined as 7.0 and 8.0, respectively. The optimum temperatures for free and immobilized enzymes were found to be 30.0 and 35.0°C, respectively. The maximum reaction rate (Vmax) and the Michaelis-Menten constant (Km) were investigated for the free and immobilized enzyme. The storage stability of acetylcholinesterase was increased when immobilized onto the novel PEI-coated silica nanoparticles. The reuse numbers of immobilized enzyme were also studied. These hybrid nanoparticles are desirable as carriers for biomedical applications.

Monitoring Enzymatic Reactions in Real Time Using Venturi Easy Ambient Sonic-Spray Ionization Mass Spectrometry

“… Our system monitored the reaction as a function of time and provided information both about transient and steady-state conversions. In our studies, acetylcholinesterase was immobilized on an organosiloxane polymer through electrostatic interactions , and was not removed by the relatively low salt concentration (20 mM ammonium bicarbonate) used herein. The flows of the feeding and sampling capillaries were allowed to equilibrate to achieve a steady-state concentration within the liquid junction on the glass microscope slide but outside the area that was functionalized with enzyme.…”

Enhanced Enzyme Activity with Ferritin Nanocages

“…The results were summarized in , respectively. The Km value of immobilized enzyme higher then the free enzyme .It can be due to the changes in the conformation of the enzyme molecules after the immobilization and it may be increased enzyme activity [13].…”

Modification of Branched Polyethyleneimine Using Mesquite Gum for Its Improved Hemocompatibility

“…B-PEI has many potential applications due to its polycationic character and water solubility [ 3 , 4 , 5 ]. In biomedical applications, it has been used as an additive to improve the specificity and efficiency of the polymerase chain reaction (PCR) for DNA amplification [ 6 ]; enzyme immobilization [ 7 , 8 ]; construction of biosensors [ 9 , 10 ]; drug delivery [ 11 , 12 ] and gene therapy [ 13 , 14 ]. For the last application, b-PEI with a molecular weight of 25 kDa has been reported as one of the polymers most used as a non-viral vector for the transport of nucleic acids due to its ability to form polyplexes with nucleic acids through electrostatic interactions between the amino groups of b-PEI and the phosphate groups of nucleic acids [ 15 , 16 , 17 ].…”