UC San Diego

Mechanosensing, the transduction of extracellular mechanical stimuli into intracellular biochemical signals, is a fundamental property of living cells. Mechanosensing is also important in engineering applications for detecting mechanical stimulation in wearable electronics, human-machine interfaces, and soft robotics. Mechanoluminescence, a representative type of mechanosensing, converts mechanical stimuli into light emission, showing promise in interactive devices, stress sensors, optical communication, structural health monitoring, and biomechanical imaging. However, current mechanoluminescent materials fall short in sensitivity, response time, energy efficiency, and lifespan compared to biological systems. Additionally, the manufacturing strategies, theoretical modeling, and novel applications of mechanoluminescent materials haven’t been fully explored yet.This thesis aims to utilize bioinspired and biohybrid approaches to develop mechanoluminescent materials and structures with improved performance and to explore their innovative manufacturing, quantitative modeling, and potential applications. First, we create bioinspired metamaterials composed of mechanoluminescent ZnS:Cu2+/PDMS composites and leverage snap-through bistability to significantly amplify strain rate and light intensity under slow loadings. These metamaterials sustain light intensity for over 1,000 cycles with minimal degradation. Second, we integrate bioluminescent cells with elastomeric chambers to develop biohybrid mechanoluminescent devices with ultra-high sensitivity (Pa~kPa), near-instantaneous response (~20 ms), and a lifetime of ~1 month. These devices are applicable in soft robotics for visualizing mechanical perturbations, illuminating dark environments, and optical signaling. Third, we embed bioluminescent cells into biocompatible hydrogels, creating mechanoluminescent living composites with ultra-high sensitivity (Pa~kPa), fast response (~20 ms), and a lifespan of ~5 months. These composites are not only 3D-printable but also exhibit remarkable mechanical toughness. We also propose a mathematical model to quantitatively predict mechanoluminescence under various loading conditions for stress sensing applications. In summary, this thesis combines bioinspired and biohybrid principles to innovate mechanoluminescent materials with superior properties, offering insights into combining the functions of both biological and engineering systems to design advanced mechanosensing materials for applications in interactive devices, stress sensors, soft robotics, and human-machine interfaces.