Fabrication and activity of silicate nanoparticles and nanosilicate-entrapped enzymes using polyethyleneimine as a biomimetic polymer.
In nature, some peptides induce precipitation of silicic acid into silica nanoparticles such as is found in marine algae called diatoms. However, polybasic polymers can act as peptide mimics; one such polymer, polyethyleneimine (PEI), has the advantage that it is stable at room temperature and is inexpensive, in comparison with synthetic peptides. We describe the fabrication and characterization of biosilicate nanoparticles formed by mimicking the peptides using PEI. Brownian motion nanoparticle tracking analysis and field emission gun scanning electron microscopy have been used for the first time to characterize nanoparticles made with tetramethyl orthosilicate (TMOS) and PEI to investigate the fundamental factors that affect particle properties. These factors include the effect of phosphate concentration, PEI molecular weight, TMOS concentration, and species of alkoxy-silane used. The properties of the particles are compared with other particles made with polymers that induce silication. Our results show that using PEI gives differences in particle size compared with previous work using other polymers that induce silication. The entrapment of enzymes during the silication process, rationale for using nonphosphate and phosphate buffers during enzyme entrapment, and the analysis of enzyme activity are also presented. Because enzymes can be entrapped during fabrication, it means that there are many future possibilities for the use of silicate nanoparticles containing enzymes, such as biosensors and biocatalytic reactors.
Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, United Kingdom. Frances.Neville@newcastle.edu.au
Frances
F
Neville
Michael J F
MJ
Broderick
Tim
T
Gibson
Paul A
PA
Millner
D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism; D040761:Biomimetic Materials / Q000737:chemistry*; D002021:Buffers; D003124:Colorimetry; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D033401:Microscopy, Acoustic; D008970:Molecular Weight; D009038:Motion; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D017646:Organosilicon Compounds / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry
D002021:Buffers; D004800:Enzymes, Immobilized; D017646:Organosilicon Compounds; D010710:Phosphates; D012821:Silanes; D017640:Silicates; C500739:tetramethyl orthosilicate; D012822:Silicon Dioxide; D011094:Polyethyleneimine; D000110:Acetylcholinesterase