Magnetically Actuated Biohybrid Microswimmers for Precise Photothermal Muscle Contraction

Abstract

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.

In vivoapplications of micro/nanorobots

“…Reproduced with permission. 128 Copyright 2022, American Chemical Society. (c) Functionalization of algae with drug-loaded nanoparticles using click chemistry and their intratracheal administration for the treatment of lung infections.…”

“…To overcome this limitation, researchers proposed the use of magnetic microrobots. 128 The microrobots were prepared by dip-coating a microalgae species ( C. pyrenoidosa ) with Fe 3 O 4 nanoparticles. In addition to enabling magnetic navigability under the guidance of rotating magnetic fields, Fe 3 O 4 nanoparticles could increase the local temperature upon NIR irradiation.…”

On Nanomachines and Their Future Perspectives in Biomedicine

“…A different example exploited the use of magnetic motors for targeting the precise locations in a rat leg. [ 100 ] The motors consisted of Chlorella pyrenoidosa coated with magnetite nanoparticles that serve to magnetic guidance and eventual heat dissipation upon NIR illumination. Chlorella pyrenoidosa was chosen as it is widely commercialized as a nutritional supplement.…”

Microrobots for Targeted Delivery and Therapy in Digestive System

“…Since researchers first reported the chemical-driven motor in 2002, miniature robots have captivated the attention of researchers from copious fields, including robotics, materials science, chemistry, and translational biomedicine due to their high potential as promising and versatile tools in a variety of biomedical, sensing, and decontamination applications. − Recently, the journal Science released the article entitled “New 125 scientific questions: exploration and discovery”. One of these questions is “Will injectable, disease-fighting nanobots ever be a reality?” Particularly, in vivo applications, such as targeted drug and cell delivery as well as therapy, have aroused attention due to the fact that micro/nanorobots enable high-precision and efficient delivery of payloads to the target site, enabling lower doses compared with conventional drug delivery systems based on passive particles and agents. − …”