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Scalable process to form magnetic nanoparticles with immobilized enzymes

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University of Idaho: Researchers from the University of Idaho have developed a novel scalable technique to produce magnetic nanoparticles containing immobilized enzymes for eventual use in applications such as pharmaceutical production and environmental remediation. 

A new process that is capable of creating enzymatically active magnetic nanoparticles with potentially high production rates has been developed by University of Idaho researchers.  Enzymes, catalysts of biological origin, enhance the rate at which chemical reactions take place, and are used industrially to produce specialized chemical products.  Researchers and chemical manufacturers already immobilize enzymes on substrates to easily separate them from reaction products for enzyme reuse and stabilization of enzyme activity.  Nanoparticles have been researched as potential substrates due to their high surface area to volume ratio, which allows a higher enzyme loading rate. Attaching enzymes to magnetic nanoparticles results in catalytically active materials with a particularly useful property: magnetic fields can controllably move these structures or hold them in place.  Previously studied methods to produce magnetic nanoparticle-enzyme complexes (MNP-Es) have been challenged with loss of enzyme activity or leaching of the enzyme from the MNP after immobilization.  The University of Idaho team has recently developed a novel, highly efficient process to create MNP-Es showing promise for improved enzyme activity, reduced leaching, and high production rates.

These researchers demonstrated that an enzyme could be modified to increase its affinity for silica or iron oxide MNPs and that the modified enzyme could be attached easily to the MNP.  Further, they were able to genetically alter E. coli bacteria to biologically produce the modified enzyme, which was efficiently separated from the bacteria and immobilized on the MNPs in a single step process, showing potential for simplified scale-up.  One complication observed in this last procedure is the undesired immobilization of E. coli biomolecules other than the target enzyme onto the MNPs.  The authors indicate that further study will be required to overcome this challenge, as well as to obtain a better understanding of the effects of NMP surface type and morphology on enzyme-MNP affinity.

According to this research report, commercial applications where MNP-Es could be particularly useful include separation and recovery of the MNP-Es from pharmaceutical products, which have a low tolerance for product contamination due to potential side effects.  MNP-Es could also act as nano-remediation tools for cleanup of large area contaminated environments such as aquifers.  The magnetic functionality would allow for precise delivery to the contaminated area, thus minimizing the amount of MNP-Es needed, and would also enable recovery of the MNP-Es for future use.   Magnetic nanoparticles could also be used as tags to trace biomolecules as they travel through natural and human-controlled environments like acquifers, sewage treatment plants and soils. 

Johnson, A.K., Zawadzka, A.M., Deobald, L.A., Crawford, R.L., Paszczynski, A.J. “Novel method for immobilization of enzymes to magnetic nanoparticles” Journal of Nanoparticle Research 10(6), 1009, 2008.