In Situ Observation of Chymotrypsin Catalytic Activity Change Actuated by Nonheating Low-Frequency Magnetic Field

Abstract

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 in situ 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.

Наноиндентирование И Механические Свойства Материалов В Субмикро- И Наношкале. Недавние Результаты И Достижения (О Б З О Р)

“…Так, приложенная сила и созданная ею деформация вызывает разнообразные отклики в живых клетках благодаря механотрансдукции [255], в частности, они меняют проницаемость клеточных мембран и метаболизм клетки, скорость ее роста и деления [253]. Силовое воздействие на биоактивные макромолекулы (ММ) ферментов влияет на их каталитическую активность [256,257]. В анализе взаимодействия различных тканей с имплантами необходимо учитывать весь комплекс биомеханических и физико-химических свойств контактирующих материалов и интерфейсов.…”

“…Г.Р. Державина и Университета Северной Каролины (США) запатентован и развит биомеханический подход к неинвазивной терапии нового поколения, заключающийся в селективной наномагнито-механическиой активации (NMMA) целевых биомолекулярных структур [256,257,[266][267][268][269][270]. Приложение принципов стрейнтроники -управления характеристиками материалов и нанообъектов посредством их контролируемой деформации -позволяет Force , N P 10 -13 10 -12 10 -11 10 -10 10 -9 10 -8 10…”

Enzyme Release from Polyion Complex by Extremely Low Frequency Magnetic Field

“…The spectrometer was calibrated against α-Fe. The transmission electron microscopy (TEM) was carried out as described previously 22 with no staining using JEM 2010(HC), 200 kV (JEOL Ltd., Japan). TEM specimens were prepared by aspirating the samples diluted (1000 times) with DI water onto a copper TEM grid.…”

“…The experimental validations of this phenomenon reported so far appear to provide support for the ability of MNPs to disrupt well-defined molecular structures, such as protein globule conformation, "lock and key" protein complex, lipid bilayer packaging or cell cytoskeleton networks. For example, magnetic field-responsive biocatalytic systems with enzyme molecules or enzyme-inhibitor complex attached to MNPs were shown to change catalytic activity in ELF MF 21,22 . Several studies have focused on applying ELF MF to increase the permeability of magnetic liposomes for dye or drug release 23 .…”

Magnetite-Gold nanohybrids as ideal all-in-one platforms for theranostics

“…While the Fe 3 O 4 part is the MRI contrast agent, it can also be used as a second binding site for functional molecules. Further, its ability for steered guidance along strong field gradients, hyperthermia applications and magneto-mechanical actuation are outstanding and may lead to even more enhanced therapies 7 , 51 – 57 . Due to these properties, targeted delivery based on magnetic NPs to malignant tissues is a promising concept in cancer biology 28 , 57 – 59 .…”