Enzyme-Immobilized Chitosan Nanoparticles as Environmentally Friendly and Highly Effective Antimicrobial Agents

Abstract

Highly effective and minimally toxic antimicrobial agents have been prepared by immobilizing glucose oxidase (GOx) onto biocompatible chitosan nanoparticles (CS-NPs). CS-NPs were prepared via ionotropic gelation and used for the immobilization of GOx via approaches of covalent attachment (CA), enzyme coating (EC), enzyme precipitate coating (EPC), and magnetic nanoparticle-incorporated EPC (Mag-EPC). EPC represents an approach consisting of enzyme covalent attachment, precipitation, and cross-linking, with CA and EC being control samples while Mag-EPC was prepared by mixing magnetic nanoparticles (Mag) with enzymes during the preparation of EPC. The GOx activities of CA, EC, EPC, and Mag-EPC were 8.57, 17.7, 219, and 247 units/mg CS-NPs, respectively, representing 26 and 12 times higher activity of EPC than those of CA and EC, respectively. EPC improved the activity and stability of GOx and led to good dispersion of CS-NPs, while Mag-EPC enabled facile magnetic separation. To demonstrate the expandability of the EPC approach to other enzymes, bovine carbonic anhydrase was also employed to prepare EPC and Mag-EPC samples for their characterizations. In the presence of glucose, EPC of GOx generated H 2 O 2 in situ, which effectively inhibited the proliferation of Staphylococcus aureus in both suspended cultures and biofilms, thereby demonstrating the potential of EPC-GOx as environmentally friendly and highly effective antimicrobial materials.

Approaches for the inhibition and elimination of microbial biofilms using macromolecular agents

“…Using the same GOx active species, Kim and Dordick et al developed a strategy for GOx immobilization onto the surface of chitosan nanoparticles. 199 In one formulation, the enzyme was immobilized onto the chitosan surface via precipitation, along with magnetic iron oxide nanoparticles to produce biohybrid nanocomposites with both oxidative activity and magnetic properties for simple extraction from solution (Fig. 8B).…”

“…8B, insets I and II). 199 Other antimicrobial enzymes have been incorporated into biohybrid systems. For example, Han and co-workers immobilized dispersin B within hydrogel nanoparticles formed by linoleic acidmodified carboxymethyl chitosan through a sonication method.…”

Agricultural and Biomedical Applications of Chitosan-Based Nanomaterials

“…Glucose oxidase (GOx) immobilized on CSNPs via covalent attachment (CA), enzyme coating (EC), enzyme precipitation coating (EPC), and magnetic nanoparticle-incorporated EPC methods were tested for the inhibition of S. aureus by enzymatically produced H 2 O 2 in the presence of glucose. From these formulations, EPC and magnetic nanoparticle-incorporated enzyme-nanoparticles demonstrated good inhibition of the bacteria in both suspension cultures and biofilms [ 106 ].…”

Antibacterial Therapeutic Agents Composed of Functional Biological Molecules

“…e molecular weight of chitosan is between 3,800 and 20,000 Da, and the ratio of D-glucosamine to N-acetyl-Dglucosamine in polymer chain is known to be the degree of deacetylation (DD) that determines most of properties of chitosan [122]. As a polycationic polymer, chitosan has been investigated as an antimicrobial material against a wide range of target organisms like algae, bacteria, yeasts, and fungi [123][124][125]. e use of chitosan is limited because of its insolubility in water, high viscosity, and tendency to coagulate with proteins at high pH.…”