Light sheet optical tweezers as a force transducer for biological tissues

The dynamic changes in tissue mechanics are crucial in distinguishing between healthy and diseased biological states. Atomic force microscopy (AFM) currently serves as the gold standard for local stiffness measurement. However, AFM has limitations such as potential damage from its sharp tip, low repeatability, and high force noise. Optical tweezers (OT) is an alternative technique capable of indenting cells with piconewton forces, capturing the reversible elastic responses. Despite these advantages, traditional OT requires high-power continuous wave lasers and exhibits low throughput, as it can only trap one indenting probe at a time. Here, we introduce a novel approach using ultra-low power light sheet-based optical tweezers with a femtosecond pulsed laser source. This innovation allows for the simultaneous indentation of bovine tendon tissues at multiple locations, facilitating the capture of both local and average elastic properties.