One reason we don't yet have powerful cyborgs roaming our streets is the batteries needed to power the electromechanical side. They are bulky and prone to running out of juice. Interestingly, the biological side – our bodies – run 24/7 on inherent chemical, mechanical, and electrical energy. Scientists have now developed a way to harness some of the body's energy to power wearables and implants.
Researchers at the University of Massachusetts Amherst have developed an ultrathin, flexible electronic mesh that integrates with living human heart cells and converts their mechanical movements into electricity.
The device, called a biohybrid mesh harvester, features numerous tiny piezoelectric generators distributed across a flexible network that living cells can grow into and around. As the cells contract, they deform these generators, producing electricity. In laboratory tests, researchers say the technology achieved more than 10 times the effective energy density of conventional energy-harvesting approaches. The research was published in the journal Science Advances.
Electronic implants and wearables such as cochlear implants, bionic prostheses, neurostimulators, cardiac implants, and diabetes-management devices are indispensable to improving the lives of hundreds of millions of people globally.
Beyond necessary medical assistive and restorative devices, health tracking has exploded in recent years, with roughly 120 million US adults, about 46% of the adult population, owning wearable devices such as smartwatches and smart rings, according to Rock Health's 2025 Consumer Adoption Survey. Then there's the long-standing fascination with augmenting human capabilities with electronics.
Almost every device in these fields has one inherent limitation: reliance on batteries. Batteries take up valuable space, add weight and rigidity, and eventually run out of charge. While recharging a smartwatch is a minor inconvenience, replacing the battery in a medical implant can require another surgery, adding costs and medical risks. Smaller or thinner batteries help address some of these problems, but they also store less energy, potentially limiting how long devices can operate.
Scientists have therefore explored alternative ways to power electronics by harvesting energy from the body itself, such as thermoelectric generators that exploit temperature differences between the body and its surroundings, and piezoelectric generators that convert mechanical movements into electricity. Researchers have also recently developed a printable textile that harvests dielectric charges from its wearer’s movements.
Piezoelectric generators are particularly attractive for implants because the body is constantly moving, from the expansion and contraction of the lungs to the rhythmic beating of the heart. When certain piezoelectric materials are compressed or stretched, they develop an electrical charge that can be collected and used to power electronic devices. They have already been tested in experimental medical implants, including pacemakers powered by the beating hearts of animals.
However, conventional piezoelectric energy harvesters are typically individual devices attached to the surface of living tissue. This centralized approach presents several challenges. For one, their mechanical properties can differ considerably from those of soft, flexible biological tissue, making seamless integration difficult. Their contact with the tissue is also largely limited to the surface, restricting how closely the harvesting elements can interact with cellular movements. Increasing the size or number of these devices can introduce additional bulk and mechanical constraints.
To overcome these limitations, the UMass Amherst researchers adopted a different approach, inspired by how living organisms distribute energy production throughout their tissues. They began by fabricating arrays of tiny ribbons of lead zirconate titanate (PZT), a piezoelectric ceramic commonly used in sensors and actuators. The material produces an electrical charge when subjected to mechanical deformation, making it suitable for harvesting energy from the movements of living cells.
The researchers then incorporated these ribbons into an ultrathin, highly flexible polymer mesh, creating a network of interconnected energy-harvesting units. Unlike conventional solid substrates, the open mesh structure provides spaces through which living cells can grow and interact with the embedded electronics. To demonstrate this, the researchers seeded the platform with human cardiac cells, which gradually grew into and around the mesh, integrating the electronic network into the developing tissue.
The resulting biohybrid structure could move and deform with the living cells, allowing the electronics to operate in close mechanical contact with the biological system. As the cardiac cells contracted, they mechanically deformed the embedded PZT ribbons, generating electrical energy through the piezoelectric effect at multiple locations across the tissue.
The distributed architecture is the research’s main innovation. Rather than relying on a relatively large energy harvester attached to one part of the tissue, the mesh integrates numerous miniature generators directly into the tissue's structure, enabling energy harvesting across a larger network of cellular interactions while maintaining the flexibility needed to accommodate biological movements. The researchers also believe that the closer integration could improve biocompatibility by reducing the mechanical mismatch between electronic components and living tissue.
According to the study, the system achieved an effective energy density more than an order of magnitude higher than existing centralized energy-harvesting approaches. In other words, the new architecture demonstrated more than a tenfold improvement in harvested energy relative to the device's effective volume.
Another potential advantage is scalability. Because the mesh is extremely thin and flexible, the researchers suggest stacking multiple layers to increase the total electricity generated without substantially increasing the device's bulk. This could eventually allow engineers to tailor the energy-harvesting capacity to the power requirements of different electronic systems.
The technology could ultimately find applications in medical implants such as pacemakers, cardiac monitoring systems, neurostimulators, and other low-power biointegrated electronics. It could also inspire new approaches to powering wearable sensors and electronic systems designed to operate in close contact with living tissue.
“Our bodies want to reject systems that come with bulk batteries, but when the device exists at the cellular level, you get vastly improved biocompatibility,” says Jun Yao, the paper’s senior author and associate professor in UMass Amherst’s Riccio College of Engineering. “The beauty of this system is how noninvasive and powerful it is.”
However, the technology remains early-stage. So far, the researchers have demonstrated it only in laboratory-grown cardiac tissue and have yet to test it in a living organism or show that it can independently power a functional medical implant. Questions also remain about long-term durability, electrical output, and biocompatibility, particularly because PZT contains the bioenemy number one – lead – and would need to be safely isolated from surrounding tissue. That said, the research lays a promising foundation for integrating electronics with biological tissue.
