Nature Sub-Journal: Comparable to optogenetics, magnetic thermal nanotechnology non-invasive treatment of Parkinson's

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Deep brain stimulation (DBS) is used in the treatment of Parkinson's, depression and other diseases
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However, since the emergence of DBS technology 30 years ago, the improvement of its hardware system and software system has not made much progress.
The need for wired devices and long-term implanted devices has been called the biggest pain point
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Non-invasive brain stimulation methods include repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and focused ultrasound techniques
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However, these non-invasive stimuli still have some side effects: high-intensity magnetic fields are required to stimulate deep brain regions during rTMS stimulation, which may cause facial pain and contraction of facial and neck muscles; ultrasound and electromagnetic waves are scattered and absorbed in brain tissue, so The penetration depth does not meet the needs of deep brain regions
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With the rapid development of science and technology, magnetic nanoparticles are widely used in biomedicine
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Magnetic nanoparticles release energy due to hysteresis in an alternating magnetic field, which increases the temperature of a local area
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The heat generation efficiency of magnetic nanoparticles directly affects the effect of their magnetic hyperthermia.
Generally, the specific power loss (SLP) measures the thermal conversion ability of magnetic nanoparticles.
The higher the SLP, the stronger the magnetic induction heating capacity
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Simply put, the magnetocaloric DBS (mDBS) technology is a method of applying a magnetic field to magnetic nanoparticles to perform deep brain stimulation.
The magnetic nanoparticles activate the transient receptor potential cation channel (TRPV1) and other heat-sensitive channels in the brain to open the TRPV1 channel.
And allow calcium ions to flow in, causing nerve excitement
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On September 22, 2021, Maastricht University Medical Center Yasin Temel's research team used non-invasive magnetic thermal deep brain stimulation technology to improve the motor symptoms of Parkinson's model mice
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The researchers optimized the alternating magnetic field coils through experiments so that these magnetic nanoparticles can exhibit high SLP in a short period of time and improve the magnetocaloric effect
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First, the researchers used genetic engineering to wrap TRPV1 in a viral vector with a neuron promoter, so that the neurons have the ability to express heat-activated ion channel proteins
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Subsequently, special magnetic nanoparticles are injected into the same area of ​​the brain.
These nanoparticles are attached to the surface of the target neuron.
When the mouse is in an alternating magnetic field, the magnetic field will quickly flip the magnetization of the nanoparticles and generate heat.
Energy
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The heat forces the temperature-sensitive ion channels to open and stimulate neurons
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Through the above experimental operations, the researchers can promote the rotational motor function of the mice after magnetic thermal stimulation of the subthalamic nucleus.
Subsequent immunofluorescence experiments found that the primary motor cortex neurons were activated, but the non-motor-related amygdala brain areas did not appear.
This activation
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Subsequently, in two Parkinsonian mouse models, magnetic stimulation of the subthalamic nucleus can quickly and lastingly improve the motor dysfunction of the mice
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Previous optogenetic experiments (activating or inhibiting) neurons in the subthalamic nucleus did not affect Parkinson's dyskinesia
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This article reveals that magnetic activation of the neural circuits in the subthalamic nucleus significantly improves dyskinesia, and at the same time, the motor cortex neurons are also activated.
This indicates that the effect of magnetic stimulation of the subthalamic nucleus is not limited to this brain area, but will spread.
To the brain area associated with the subthalamic nucleus, it exerts the above-mentioned therapeutic effect
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[References] 1.
https://doi.
org/10.
1038/s41467-021-25837-4 The pictures in the text are from the references