Magnetic field remotely controlled selective biocatalysis

Abstract

M aterials that efficiently release biological molecules or therapeutic chemicals on demand using exposure to remotely controlled and safe external sources of energy, such as magnetic fields, could find applications for drug delivery 1 , biotechnology 2,3 and biosensors 4 . Because live tissue and synthetic polymers are not responsive to weak magnetic fields, the development of magnetic-field-responsive soft materials has been reported by combining magnetic nanoparticles and stimuli-responsive soft materials 5 . Magnetic nanoparticles interact with magnetic fields and transduce magnetic field energy into physical or chemical changes in the soft material. Materials that control enzymatic processes are one example of such soft materials. Enzymes are extensively used to change or degrade colloidal particles, capsules, and their assemblies to trigger release of the cargo via biocatalytic reactions 6,7 .In all eukaryotes, metabolic pathways are precisely organized and regulated. This precise control is based in part on the high selectivity of biocatalytic reactions and controlled transport of chemicals and biomacromolecules across membranes that compartmentalize cells, organelles and organs. Highly selective biocatalysis alone cannot orchestrate complex systems of biochemical reactions without the supporting role of signal-triggered synthesis, release, secretion, conversion and degrading processes that take place in different compartments in cells and organs. Despite being highly selective, enzymes cannot provide 100% selectivity. In particular, enzymes could interact with a number of substrates of a similar chemical structure (for example, proteases are highly promiscuous catalysts), be degraded by other enzymes or even by self-digestion upon secretion into a complex biological environment, or undergo undesired aggregation, crystallization or nonspecific adsorption, which would strongly damage the efficiency of the biocatalytic process. However, the overall high specificity of biocatalytic processes is strengthened by localizing the enzymatic reactions within a specific environment and spatial compartments.Inspired by this hierarchical design in live systems, diverse stimuli-responsive functional materials have been reported, involving various architectures that respond to changes in magnetic fields [8][9][10] . However, it remains challenging to create a reactive system that preserves enzyme molecules from destructive environments and undesired interactions while being able to initiate the designated reaction when needed. Different approaches have been developed to preserve enzymes for storage and delivery before activating them on demand in a magnetic field at the targeted location. A number of studies aimed at controlling the kinetics of biocatalytic reactions in model systems [11][12][13][14][15] have explored magnetic-field-triggered changes of the local concentration and mobility of enzymes. However, it is difficult to apply many of such approaches to live tissue because of limitations associated with degradat...

Nanocomposite Polymer Scaffolds Responding under External Stimuli for Drug Delivery and Tissue Engineering Applications

“…The drawbacks are the complexity of use, the cost and the specific implementation for a surgeon. The typical ranges of use in frequency of the magnetic field goes from 100 < f < 437 kHz; 30 < time < 60 min; B < 100 mT . Current issues with the use of magnetic nanomaterials as stimuli‐responsive systems is that they should be as least cytotoxic as possible.…”

“…The typical ranges of use in frequency of the magnetic field goes from 100 < f < 437 kHz; 30 < time < 60 min; B < 100 mT. [42,43] Current issues with the use of magnetic nanomaterials as stimuli-responsive systems is that they should be as least cytotoxic as possible. Even if metallic NPs or cobalt or zinc-doped ferrites would be highly preferred for their high saturation magnetization, they would induce important toxicity because of the release of heavy metals.…”

Multifunctional and Stimuli‐Responsive Magnetic Nanoparticle‐Based Delivery Systems for Biomedical Applications

“…Zakharchenko et al. investigated the magnetic field–responsive compartmentalization of biocatalytic reactions for the remotely controlled release of drugs or (bio)chemicals . The concept is implemented by fabricating two distinctive magnetic core–shell nanoparticles, E and S, where E‐particles are grafted with PAA‐b‐PPEGMA and conjugated with the enzyme, and S‐particles are similarly decorated with PAA‐b‐PPEGMA and then loaded with the substrate.…”

On the shape of invading population in anisotropic environments

“…In particular, the presence of oriented factors in environment lead to occurrence of directed movement patterns, different from pure diffusion (Armsworth and Bode 1999, Belgacem and Cosner 1995, Cantrell et al 2006. In this concern, it is worthwhile to mention also the modern technologies of controlled drug delivery, using an external oriented magnetic field (Zakharchenko et al 2018), and the implants based on arrays of oriented TiO 2 nanotubes, which control the directed release of drugs (Losic et al 2015, Wang et al 2017.…”