Magnetomechanical
modulation of biochemical processes is a promising
instrument for bioengineering and nanomedicine. This work demonstrates
two approaches to control activity of an enzyme, α-chymotrypsin
immobilized on the surface of gold-coated magnetite magnetic nanoparticles
(GM-MNPs) using a nonheating low-frequency magnetic field (LF MF).
The measurement of the enzyme reaction rate was carried out <i>in situ</i> during exposure to the magnetic field. The first
approach involves α-chymotrypsin-GM-MNPs conjugates, in which
the enzyme undergoes mechanical deformations with the reorientation
of the MNPs under LF MF (16–410 Hz frequency, 88 mT flux density).
Such mechanical deformations result in conformational changes in α-chymotrypsin
structure, as confirmed by infrared spectroscopy and molecular modeling,
and lead to a 63% decrease of enzyme initial activity. The second
approach involves an α-chymotrypsin–GM-MNPs/trypsin inhibitor–GM-MNPs
complex, in which the activity of the enzyme is partially inhibited.
In this case the reorientation of MNPs in the field leads to disruption
of the enzyme–inhibitor complex and an almost 2-fold increase
of enzyme activity. The results further demonstrate the utility of
magnetomechanical actuation at the nanoscale for the remote modulation
of biochemical reactions