In the burgeoning field of bioactuators, a significant stride has been made by Mizuki Nakamura, a researcher at the Department of Biomedical Engineering at Shinshu University in Japan. Nakamura’s work, published in the journal *Advanced Intelligent Systems* (which translates to *Advanced Intelligent Systems* in English), focuses on enhancing the Hill’s muscle model to better understand and control tissue-engineered skeletal muscle (TESM). This advancement could have profound implications for the energy sector, particularly in the development of biohybrid actuators and energy-harvesting devices.
Nakamura’s research addresses a critical gap in current bioactuator studies: the lack of attention to control engineering aspects. “Many studies focus on constructing muscle tissue, but they often overlook the nuances of controlling these tissues effectively,” Nakamura explains. To bridge this gap, Nakamura developed an enhanced Hill’s muscle model (EHMM) that accounts for the mechanical property changes between the static and contracted states of TESM.
The conventional Hill’s muscle model (CHMM), widely used for native muscle, proved inadequate when applied to TESM. Parameters derived from elongation tests failed to replicate the rapid tension changes observed in isometric contraction tests. To overcome this limitation, Nakamura introduced a seven-element EHMM, incorporating an active viscoelastic branch in parallel with the static branch. This innovation models the actin–myosin interactions that occur during muscle contraction.
“By incorporating viscoelastic changes during contraction, our model provides a more accurate representation of TESM behavior,” Nakamura states. The model was further refined by removing a negligible viscous element, resulting in a six-element EHMM that closely matches experimental data.
The practical applications of this research are substantial. For instance, in the development of reverse-action tweezers driven by TESM, the CHMM significantly overestimated displacement, whereas the six-element EHMM provided precise predictions. This accuracy is crucial for designing and controlling biohybrid actuators, which have potential applications in various fields, including energy harvesting and robotics.
Nakamura’s work not only offers a physiological description of TESM contraction but also lays the groundwork for future research in feedback control and advanced biohybrid actuator development. “Our model provides a foundation for more sophisticated control strategies, which could lead to more efficient and reliable bioactuators,” Nakamura adds.
As the energy sector continues to explore innovative solutions for sustainable and efficient energy production, bioactuators hold promise as a viable option. Nakamura’s enhanced Hill’s muscle model represents a significant step forward in this direction, offering a more accurate and controllable approach to bioactuator development. This research not only advances our understanding of muscle tissue engineering but also paves the way for future advancements in biohybrid technologies, potentially revolutionizing the energy sector.