Chemodynamic
therapy (CDT) is an emerging strategy for cancer treatment
based on Fenton chemistry, which can convert endogenous H2O2 into toxic ·OH. However, the limited endocytosis
of passive CDT nanoagents with low penetrating capability resulted
in unsatisfactory anticancer efficacy. Herein, we propose the successful
fabrication of a self-propelled biodegradable nanomotor system based
on hollow MnO2 nanoparticles with catalytic activity for
active Fenton-like Mn2+ delivery and enhanced CDT. Compared
with the passive counterparts, the significantly improved penetration
of nanomotors with enhanced diffusion is demonstrated in both the
2D cell culture system and 3D tumor multicellular spheroids. After
the intracellular uptake of nanomotors, toxic Fenton-like Mn2+ is massively produced by consuming overexpressed intracellular glutathione
(GSH), which has a strong scavenging effect on ·OH, thereby leading
to enhanced cancer CDT. The as-developed MnO2-based nanomotor
system with enhanced penetration and endogenous GSH scavenging capability
shows much promise as a potential platform for cancer treatment in
the near future.
Inducing neural stem cells to differentiate and replace degenerated functional neurons represents the most promising approach for neural degenerative diseases including Parkinson's disease, Alzheimer's disease, etc. While diverse strategies have been proposed in recent years, most of these are hindered due to uncontrollable cell fate and device invasiveness.Here, we report a minimally invasive micromotor platform with biodegradable helical Spirulina plantensis (S. platensis) as the framework and superparamagnetic Fe 3 O 4 nanoparticles/piezoelectric BaTiO 3 nanoparticles as the built-in function units. With a low-strength rotational magnetic field, this integrated micromotor system can perform precise navigation in biofluid and achieve single-neural stem cell targeting. Remarkably, by tuning ultrasound intensity, thus the local electrical output by the motor, directed differentiation of the neural stem cell into astrocytes, functional neurons (dopamine neurons, cholinergic neurons), and oligodendrocytes, can be achieved. This micromotor platform can serve as a highly controllable wireless tool for bioelectronics and neuronal regenerative therapy.
Micro/nanomotors are attracting booming research enthusiasm with their revolutionary potential in biomedicine, sensing, and nanoengineering. Among the motors proposed, magnetic micro/nanomotors are of great interest with their high controllability and field biocompatibility. Yet the fabrication of magnetic actuated especially helical motors requires expensive and complicated instruments, 3D printing or glancing angle deposition, etc. Here, a soft and biocompatible helical poly(vinyl alcohol) (PVA) hydrogel motor via a versatile set-up is engineered. The obtained helical hydrogel motor offers high capacity for chemokine CXCL12 and superparamagnetic iron oxide (Fe 3 O 4 ) nanoparticles, which can then allow magnetic manipulation. With a low strength rotating magnetic field, the system is able to perform 3D precision navigation, necessary to steer the robotic system to a model diseased area. The chemokine cues from the hydrogel motor, acting as the synthetic leader cell, then directs immune T cell chemotactic migration. In a previously reported cell manipulating motor system, towing or pushing a single/two cell was demonstrated, with limited efficiency. This motor platform represents a novel approach for directing endogenous cell chemotaxis and organizing immune response.
Various
strategies have been designed for myotube contraction and
skeletal muscle stimulation in recent years, aiming in the field of
skeletal muscle tissue engineering and bionics. However, most of the
current approaches lack controllability and adaptability for precise
stimulation, especially at the microlevel. Herein, wireless and precise
activation of muscle by using magnetic biohybrid microswimmers in
combination with near-infrared (NIR) laser irradiation is successfully
demonstrated. Biohybrid microswimmers are fabricated by dip-coating
superparamagnetic Fe3O4 nanoparticles onto the chlorella microalgae, thus endowing robust navigation in
various biological media due to magnetic actuation. Under the guidance
of a rotating magnetic field, the engineered microswimmer can achieve
precise motion toward a single C2C12-derived myotube. Upon NIR irradiation,
the photothermal effect from the incorporated Fe3O4 nanoparticles results in local temperature increments of
approximately 5 °C in the targeted myotube, which could efficiently
trigger the contraction of myotube. The mechanism underlying this
phenomenon is a Ca2+-independent case involving direct
actin–myosin interactions. In vivo muscle
fiber contraction and histological test further demonstrate the effectiveness
and biosafety of our design. The as-developed biohybrid microswimmer-based
strategy is possible to provide a renovation for tissue engineering
and bionics.
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