Packaging actomyosin-based biomolecular motor-driven devices for nanoactuator applications

Biomolecular motors such as the muscle protein myosin with its partner protein actin hold great promise for actuation in hybrid nanoscale biomicroelectromechanical systems devices (bio-MEMS), particularly for future biomedical applications that involve highly localized delivery of biomolecules over short distances (e.g., micrometers) to specific tissue or cellular locations. Two fundamental issues in the construction and packaging of actomyosin-based nanoactuators are the ability to electrically insulate microelectrical components while maintaining both biocompatibility and also compatibility with our functional assays for prototype development and identification of conditions for storage of assembled devices. Here, we show that sputter coating with SiO₂ provides a straightforward method for electrical insulation that can be readily integrated into existing assays of myosin function in a bio-MEMS setting. We also report using in vitro motility analysis that both rabbit skeletal muscle heavy meromyosin (HMM) and fish (Fundulus heteroclitus) myosin remained functional for at least six days in a bio-MEMS setting when hydrating conditions were maintained. The speed of actin sliding was faster after six days when rabbit HMM was stored in 10% DMSO than in its absence, but there was no effect of DMSO during storage on fish myosin. The speed of actin translocation by fish myosin was significantly increased when adenosine 5´-triphosphate (ATP), the chemical energy source for myosin function, was replaced by the analog 2´ deoxy-ATP, as has been previously reported for rabbit HMM. Taken together, these results provide new direction for modulation and control of actomyosin-based nanoactuators and also for long-term storage of assembled nanoactuators.