Session 8

Harvesting energy directly from the human body offers a new paradigm to power wearable electronics and implantable biomedical devices without the need to replace batteries. For patients with implantable devices such as cardiac pacemakers, there is an urgent need to improve the quality of patients' post-implantation life by eliminating the risks and costs associated with battery replacement surgeries. Here, we demonstrate the designs, characterizations, and pre-clinical studies of compact implantable devices showing significant improvement in the electro-mechanical conversion efficiency. The proposed energy harvesting designs combine the thin film piezoelectric materials development with geometric mechanics towards seamless integration with existing medical implants such as the pacemakers. Various energy harvesting device prototypes have been developed using piezoelectric composite films made of mesoporous PVDF-TrFE including Kirigami-inspired energy harvester, Bioinspired helical energy harvesting device with cardiac sensing function, multi-buckled-beam energy harvester, Dual-cantilever energy harvester, and lead-in-tube design. The results based on those five geometrically designed thin film energy harvesting prototypes showed great promise to provide electrical energy for powering implantable devices. Moreover, in vivo studies demonstrated feasible clinical translation in porcine models. A sealed energy harvesting device was inserted, together with the pacemaker leads, using a standard implantation procedure. Evaluations under different anchoring positions, different heart rates, and drug treatment conditions were performed in right ventricles of porcine models. Both in vitro and in vivo results demonstrate the energy harvesters' capability to provide significant electrical energy directly from the motion of a pacemaker lead. In conclusion, the proposed implantable cardiac energy harvesting strategy can be extended to power other medical implants and wearable devices alike without the limit of the battery.

To perform their function, biological systems need to operate across multiple scales. Current techniques in structural and cellular biology lack either the resolution or the context to observe the structure of individual biomolecules in their natural environment and are often hindered by artifacts. My lab builds tools to observe molecular structures in their native cellular environment. Using the power of cryo-electron tomography to image biomolecules at molecular resolution in situ, we are building tools to make compatible with, and directly comparable to, biophysical and cell biology experiments, capturing the structural behavior of macromolecules in action under controlled conditions. I will show how we used these techniques to reveal the structure of LRRK2, the greatest known genetic contributor to Parkinson's disease, and to unveil the molecular architecture of processes in bacterial cell biology.