9 research outputs found
In-vivo Studies of Ultrasound-activated Drug-loaded Porous Silicon Nanoparticles for Cancer Therapy Application
It is investigated the therapeutic efficacy of combined action of ultrasound and porous silicon nanoparticles loaded with anticancer drug doxorubicin by using an experimental cancer model of lung Lewis carcinoma in vivo. Time dependences of growth of the primary tumor with introduced nanoparticles and without them, as well as the life span of mice after exposure to therapeutic ultrasound with intensity of 1W/cm2 and frequency of 1 MHz were studied. The obtained results show the effectiveness of inhibiting the growth of primary tumor site, as well as slowing the process of metastasis, in the case of combined action of ultrasound and drug-loaded porous silicon nanoparticles that indicates the prospect of latter as sonosensitizers and nanocontainers for the delivery and controlled release of drugs in sonodynamic therapy of malignant tumors.
Keywords: silicon nanoparticles, nanocontainers, medical ultrasound, sonodynamic therapy, sonosensitizer
<i>In Situ</i> Observation of Chymotrypsin Catalytic Activity Change Actuated by Nonheating Low-Frequency Magnetic Field
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