Targeted cell delivery by a magnetically actuated microrobot with a porous structure is a promising technique to enhance the low targeting efficiency of mesenchymal stem cell (MSC) in tissue regeneration. However, the relevant research performed to date is only in its proof-of-concept stage. To use the microrobot in a clinical stage, biocompatibility and biodegradation materials should be considered in the microrobot, and its efficacy needs to be verified using an in vivo model. In this study, we propose a human adipose–derived MSC–based medical microrobot system for knee cartilage regeneration and present an in vivo trial to verify the efficacy of the microrobot using the cartilage defect model. The microrobot system consists of a microrobot body capable of supporting MSCs, an electromagnetic actuation system for three-dimensional targeting of the microrobot, and a magnet for fixation of the microrobot to the damaged cartilage. Each component was designed and fabricated considering the accessibility of the patient and medical staff, as well as clinical safety. The efficacy of the microrobot system was then assessed in the cartilage defect model of rabbit knee with the aim to obtain clinical trial approval.
Nanorobots are safe
and exhibit powerful functionalities, including
delivery, therapy, and diagnosis. Therefore, they are in high demand
for the development of new cancer therapies. Although many studies
have contributed to the progressive development of the nanorobot system
for anticancer drug delivery, these systems still face some critical
limitations, such as potentially toxic materials in the nanorobots,
unreasonable sizes for passive targeting, and the lack of several
essential functions of the nanorobot for anticancer drug delivery
including sensing, active targeting, controlling drug release, and
sufficient drug loading capacity. Here, we developed a multifunctional
nanorobot system capable of precise magnetic control, sufficient drug
loading for chemotherapy, light-triggered controlled drug release,
light absorption for photothermal therapy, enhanced magnetic resonance
imaging, and tumor sensing. The developed nanorobot system exhibits
an in vitro synergetic antitumor effect of photothermal
therapy and chemotherapy and outstanding tumor-targeting efficiency
in both in vitro and in vivo environments.
The results of this study encourage further explorations of an efficient
active drug delivery system for cancer treatment and the development
of nanorobot systems for other biomedical applications.
Targeted drug delivery using a microrobot is a promising technique capable of overcoming the limitations of conventional chemotherapy that relies on body circulation. However, most studies of microrobots used for drug delivery have only demonstrated simple mobility rather than precise targeting methods and prove the possibility of biodegradation of implanted microrobots after drug delivery. In this study, magnetically guided self‐rolled microrobot that enables autonomous navigation‐based targeted drug delivery, real‐time X‐ray imaging, and microrobot retrieval is proposed. The microrobot, composed of a self‐rolled body that is printed using focused light and a surface with magnetic nanoparticles attached, demonstrates the loading of doxorubicin and an X‐ray contrast agent for cancer therapy and X‐ray imaging. The microrobot is precisely mobilized to the lesion site through automated targeting using magnetic field control of an electromagnetic actuation system under real‐time X‐ray imaging. The photothermal effect using near‐infrared light reveals rapid drug release of the microrobot located at the lesion site. After drug delivery, the microrobot is recovered without potential toxicity by implantation or degradation using a magnetic‐field‐switchable coiled catheter. This microrobotic approach using automated control method of the therapeutic agents‐loaded microrobot has potential use in precise localized drug delivery systems.
We
described a magnetic chitosan microscaffold tailored for applications
requiring high biocompatibility, biodegradability, and monitoring
by real-time imaging. Such magnetic microscaffolds exhibit adjustable
pores and sizes depending on the target application and provide various
functions such as magnetic actuation and enhanced cell adhesion using
biomaterial-based magnetic particles. Subsequently, we fabricated
the magnetic chitosan microscaffolds with optimized shape and pore
properties to specific target diseases. As a versatile tool, the capability
of the developed microscaffold was demonstrated through in
vitro laboratory tasks and in vivo therapeutic
applications for liver cancer therapy and knee cartilage regeneration.
We anticipate that the optimal design and fabrication of the presented
microscaffold will advance the technology of biopolymer-based microscaffolds
and micro/nanorobots.
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