Magnetic Iron Oxide Nanoparticle Seeded Growth of Nucleotide Coordinated Polymers

Abstract

Introducing functional molecules to the surface of magnetic iron oxide nanoparticles (NPs) is of critical importance. Most previously reported methods were focused on surface ligand attachment either by physisorption or covalent conjugation, resulting in limited ligand loading capacity. In this work, we report the seeded growth of a nucleotide coordinated polymer shell, which can be considered as a special form of adsorption by forming a complete shell. Among all the tested metal ions, Fe 3+ is the most efficient for this seeded growth. A diverse range of guest molecules including small organic dyes, proteins, DNA, and gold NPs can be encapsulated in the shell. All these molecules were loaded at a much higher capacity compared to that on the naked iron oxide NP core, confirming the advantage of the coordination polymer (CP) shell. In addition, the CP shell provides better guest protein stability compared to simple physisorption, while retaining guest activity as confirmed by the entrapped glucose oxidase assay. The use of this system as a peroxidase nanozyme and as a glucose biosensor was demonstrated, detecting glucose down to 1.4 µM with excellent stability. Together, this work describes a new way of functionalizing inorganic materials with a biocompatible shell.

Nanozyme applications in biology and medicine: an overview

“…Carbon-based nanomaterial, such as fullerene, graphene, carbon nanotubes and their derivatives, mimic various natural enzymes [97]. The peroxidase-like activity of CNTs have reported in another study [98].…”

Self‐Assembly of Nucleobase, Nucleoside and Nucleotide Coordination Polymers: From Synthesis to Applications

“…While the nature of these interactions was relatively well‐known, its self‐assembly behavior was not investigated until recently. We explored Fe 3+ /AMP CPs in a similar way to the above Zn 2+ experiment . It was found that pH was important and CP nanoparticle formation was inhibited at acidic pH.…”

“…In addition to proteins, it is also possible to entrap nanomaterials in such CPs. An interesting example is the growth of Fe 3+ /AMP on magnetic iron oxide nanoparticles (Figure A) . In this case, the surface of magnetic nanoparticles can be coated with a thin CP layer of a few nm as shown in Figure B–C.…”

In-Situ Self-Assembly of Zinc/Adenine Hybrid Nanomaterials for Enzyme Immobilization

“…To solve these issues, immobilization techniques are considered, because binding of free enzymes to supports limits their mobility [8]. What is more, some immobilized enzymes could show more robust activity than free enzymes [9][10][11][12].…”

“…Because of their mild polymerization conditions, porosity and high guest-entrapment efficiency [11], CPs could play important roles in many fields, including catalysis [12], biological detection [28], imaging [29,30], gas storage [31] and drug delivery [32].…”