Self‐sustainable energy generation represents a new frontier to significantly extend the lifetime and effectiveness of implantable biomedical devices. In this work, a piezoelectric energy harvester design is employed to utilize the bending of the lead of a cardiac pacemaker or defibrillator for generating electrical energy with minimal risk of interfering with cardiovascular functions. The proposed energy harvester combines flexible porous polyvinylidene fluoride–trifluoroethylene thin film with a buckled beam array design for potentially harvesting energy from cardiac motion. Systematic in vitro experimental evaluations are performed by considering complex parameters in practical implementations. Under various mechanical inputs and boundary conditions, the maximum electrical output of this energy harvester yields an open circuit voltage (peak to peak) of 4.5 V and a short circuit current (peak to peak) of 200 nA, and that energy is sufficient to self‐power a typical pacemaker for 1 d. A peak power output of 49 nW is delivered at an optimal resistor load of 50 MΩ. The scalability of the design is also discussed, and the reported results demonstrate the energy harvester's capability of providing significant electrical energy directly from the motions of pacemaker leads, suggesting a paradigm for biomedical energy harvesting in vivo.
Biomedical self‐sustainable energy generation represents a new frontier of power solution for implantable biomedical devices (IMDs), such as cardiac pacemakers. However, almost all reported cardiac energy harvesting designs have not yet reached the stage of clinical translation. A major bottleneck has been the need of additional surgeries for the placements of these devices. Here, integrated piezoelectric‐based energy harvesting and sensing designs are reported, which can be seamlessly incorporated into existing IMDs for ease of clinical translation. In vitro experiments validate the energy harvesting process by simulating the bending and twisting motion during heart cycle. Clinical translation is demonstrated in four porcine hearts in vivo under various conditions. Energy harvesting strategy utilizes pacemaker leads as a means of reducing the reliance on batteries and demonstrates the charging ability for extending the lifetime of a pacemaker battery by 20%, which provides a promising self‐sustainable energy solution for IMDs. The additional self‐powered blood pressure sensing is discussed, and the reported results demonstrate the potential in alerting arrhythmias by monitoring the right ventricular pressure variations. This combined cardiac energy harvesting and blood pressure sensing strategy provides a multifunctional, transformative while practical power and diagnosis solution for cardiac pacemakers and next generation of IMDs.
more » « less- NSF-PAR ID:
- 10458040
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Healthcare Materials
- Volume:
- 9
- Issue:
- 11
- ISSN:
- 2192-2640
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
more » « less
Abstract Self‐sustainable energy generation represents a new frontier to greatly extend the lifetime and effectiveness of implantable biomedical devices, such as cardiac pacemakers and defibrillators. However, there is a lack of promising technologies which can efficiently convert the mechanical energy of the beating heart to electrical energy with minimal risk of interfering with the cardiovascular functions. Here a unique design is presented based on existing pacemaker leads tailored for compact energy harvesting. This new design incorporates flexible porous polyvinylidene fluoride‐trifluoroethylene thin film within a dual‐cantilever structure, which wraps around the pacemaker lead with two free ends sticking out for harvesting energy from the heart's motion. Under various anchor methods of the lead, the maximum electrical output yields 0.5 V and 43 nA under the frequency of 1 Hz. It is found that adding a proof mass of 31.6 mg on the dual‐cantilever tip results in a 1.82 times power enhancement. The scalability of the design is also demonstrated, e.g., by connecting two such units in parallel, their simultaneous vibration can together contribute to energy conversion. Collectively, this study implies that sufficient electrical energy can be converted from the kinetic energy of a pacemaker lead especially at low frequencies to sustain operations.
-
more » « less
Abstract Harvesting biomechanical energy to power implantable electronics such as pacemakers has been attracting great attention in recent years because it replaces conventional batteries and provides a sustainable energy solution. However, current energy harvesting technologies that directly interact with internal organs often lack flexibility and conformability, and they usually require additional implantation surgeries that impose extra burden to patients. To address this issue, here a Kirigami inspired energy harvester, seamlessly incorporated into the pacemaker lead using piezoelectric composite films is reported, which not only possesses great flexibility but also requires no additional implantation surgeries. This lead‐based device allows for harvesting energy from the complex motion of the lead caused by the expansion‐contraction of the heart. The device's Kirigami pattern has been designed and optimized to attain greatly improved flexibility which is validated via finite element method (FEM) simulations, mechanical tensile tests, and energy output tests where the device shows a power output of 2.4 µW. Finally, an in vivo test using a porcine model reveals that the device can be implanted into the heart straightforwardly and generates voltages up to ≈0.7 V. This work offers a new strategy for designing flexible energy harvesters that power implantable electronics.
-
more » « less
Abstract Every heartbeat originates from a tiny tissue in the heart called the sinoatrial node (SAN). The SAN harbors only ≈10 000 cardiac pacemaker cells, initiating an electrical impulse that captures the entire heart, consisting of billions of cardiomyocytes for each cardiac contraction. How these rare cardiac pacemaker cells (the electrical source) can overcome the electrically hyperpolarizing and quiescent myocardium (the electrical sink) is incompletely understood. Due to the scarcity of native pacemaker cells, this concept of source–sink mismatch cannot be tested directly with live cardiac tissue constructs. By exploiting TBX18 induced pacemaker cells by somatic gene transfer, 3D cardiac pacemaker spheroids can be tissue‐engineered. The TBX18 induced pacemakers (sphTBX18) pace autonomously and drive the contraction of neighboring myocardium in vitro. TBX18 spheroids demonstrate the need for reduced electrical coupling and physical separation from the neighboring ventricular myocytes, successfully recapitulating a key design principle of the native SAN. β‐Adrenergic stimulation as well as electrical uncoupling significantly increase sphTBX18s' ability to pace‐and‐drive the neighboring myocardium. This model represents the first platform to test design principles of the SAN for mechanistic understanding and to better engineer biological pacemakers for therapeutic translation.
-
Electrode-based electrical stimulation underpins several clinical bioelectronic devices, including deep-brain stimulators and cardiac pacemakers. However, leadless multisite stimulation is constrained by the technical difficulties and spatial-access limitations of electrode arrays. Optogenetics offers optically controlled random access with high spatiotemporal capabilities, but clinical translation poses challenges. Here we show tunable spatiotemporal photostimulation of cardiac systems using a non-genetic platform based on semiconductor-enabled biomodulation interfaces. Through spatiotemporal profiling of photoelectrochemical currents, we assess the magnitude, precision, accuracy and resolution of photostimulation in four leadless silicon-based monolithic photoelectrochemical devices. We demonstrate the optoelectronic capabilities of the devices through optical overdrive pacing of cultured cardiomyocytes (CMs) targeting several regions and spatial extents, isolated rat hearts in a Langendorff apparatus, in vivo rat hearts in an ischaemia model and an in vivo mouse heart model with transthoracic optical pacing. We also perform the first, to our knowledge, optical override pacing and multisite pacing of a pig heart in vivo. Our systems are readily adaptable for minimally invasive clinical procedures using our custom endoscopic delivery device, with which we demonstrate closed-thoracic operations and endoscopic optical stimulation. Our results indicate the clinical potential of the leadless, lightweight and multisite photostimulation platform as a pacemaker in cardiac resynchronization therapy (CRT), in which lead-placement complications are common.more » « less
