Enhancing the Reusability of Endoglucanase-Gold Nanoparticle Bioconjugates by Tethering to Polyurethane Microspheres

Abstract

The synthesis of polyurethane microsphere-gold nanoparticle "core-shell" structures and their use in the immobilization of the enzyme endoglucanase are described. Assembly of gold nanoparticles on the surface of polymer microspheres occurs through interaction of the nitrogens in the polymer with the nanoparticles, thereby precluding the need for modifying the polymer microspheres to enable such nanoparticle binding. Endoglucanse could thereafter be bound to the gold nanoparticles decorating the polyurethane microspheres, leading to a highly stable biocatalyst with excellent reuse characteristics. The immobilized enzyme retains its biocatalytic activity and exhibits improved thermal stability relative to free enzyme in solution. The high surface area of the host gold nanoparticles renders the immobilized enzyme "quasi free", while at the same time retaining advantages of immobilization such as ease of reuse, enhanced temporal and thermal stability, etc.

Polyurethane-gold and polyurethane-silver nanoparticles conjugates for efficient immobilization of maltogenase

“…It is also known that primary amines bind to colloidal gold through nitrogen atoms. This indicates binding of colloidal gold particles to the PU microparticles through nitrogen atoms in polyurethane [10,22,23]. For comparison reason, PU carrier was modified with silver nanoparticles also.…”

“…Synthesized PU/Au-NPs composites also were applied for immobilization of enzymes. High catalytic activity, reusability and pH/temperature stability for immobilized enzymes were observed [22,23].…”

“…However, both Au-NPs and Ag-NPs are widely used for immobilization of various enzymes due to their high surface area to volume ratio, biocompatibility and the unique chemical and physical properties [22,23]. The modification of nanoparticles with enzyme molecules provides a unique biofunctionality of surface [24].…”

Polyurethane as Carriers of Antituberculosis Drugs

“…The synthesis of PU microsphere-gold nanoparticle "core-shell" structures and their use in the immobilization of the enzyme endoglucanase are described (Phadtare et al, 2004). Assembly of gold nanoparticles on the surface of polymer microspheres occurs through interaction of the nitrogens in the polymer with the nanoparticles, thereby precluding the need for modifying the polymer microspheres to enable such nanoparticle binding.…”

Production of Extracellular Isoamylase and Endoglucanase by Entrapped Spores of Rhizopus oryzae PR7

“…Although a number of amylase and cellulase producing microbes were immobilized [12,16,17], a few reports are available on immobilization of microbial cells for using amylase as well as endoglucanase producing machinery of the same cell.…”