Young Kevin W, Kuo Bill P-P, O'Connor Shawn M, Radic Stojan, Lieber Richard L
Department of Bioengineering, University of California, San Diego, La Jolla, California; VA San Diego Healthcare System, San Diego, California.
Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California.
Biophys J. 2017 Feb 28;112(4):805-812. doi: 10.1016/j.bpj.2016.12.046.
Muscle force is dictated by micrometer-scale contractile machines called sarcomeres. Whole-muscle force drops from peak force production to zero with just a few micrometers of sarcomere length change. No current technology is able to capture adequate dynamic sarcomere data in vivo, and thus we lack fundamental data needed to understand human movement and movement disorders. Methods such as diffraction, endoscopy, and optical coherence tomography have been applied to muscle but are prohibitively invasive, sensitive to motion artifact, and/or imprecise. Here, we report dynamic sarcomere length measurement in vivo using a combination of our recently validated resonant reflection spectroscopy method combined with optical frequency domain interferometry. Using a 250-μm-wide fiber optic probe, we captured nanometer sarcomere length changes from thousands of sarcomeres on the sub-millisecond timescale during whole-muscle stretch and twitch contraction. We believe that this demonstrates the first large-scale sensing of sarcomere dynamics in vivo, which is a necessary first step to understand movement disorders and to create patient-specific surgical interventions and rehabilitation.
肌肉力量由称为肌节的微米级收缩机器决定。随着肌节长度仅改变几微米，整块肌肉的力量就会从峰值力量产生降至零。目前没有技术能够在体内获取足够的动态肌节数据，因此我们缺乏理解人体运动和运动障碍所需的基础数据。诸如衍射、内窥镜检查和光学相干断层扫描等方法已应用于肌肉，但具有侵入性过大、对运动伪影敏感和/或不精确等问题。在此，我们报告了使用我们最近验证的共振反射光谱法与光学频域干涉测量法相结合，在体内进行动态肌节长度测量。使用一个250微米宽的光纤探头，我们在整块肌肉拉伸和抽搐收缩的亚毫秒时间尺度上，从数千个肌节中捕捉到了纳米级的肌节长度变化。我们认为，这展示了首次在体内对肌节动力学进行大规模传感，这是理解运动障碍以及创建针对患者的手术干预和康复方法的必要第一步。
