Biomedical Engineering

Bioelectric implants designed to augment the body’s natural electric impulses? Developments in bioelectronic technology make that reality increasingly available. One of the most cutting-edge sectors of medical device research, bioelectric implants seem like the stuff of science fiction. Drawing from biology, electrical engineering, nanotechnology, medicine, biomedical engineering, and other fields, bioelectronic technology blurs the boundaries of the human / mechanical divide. For U.S. Translation Company, the bioelectronics frontier offers yet another exciting development in the life sciences sector — an industry that continues to intrigue and reward us.

Cyborg humans via medical devices

Merriam-Webster tells us that a cyborg is “a bionic human,” and that bionic means “having artificial body parts, especially electromechanical ones.” Though not as sensational as pop-culture augmented humans (e.g., Robocop, Inspector Gadget, The Six Million Dollar Man), cyborgs indeed walk among us. A lot of them. They’re not exotic in the least: they’re our grandmas and cousins and the person down the block. In fact, we’ve been getting cyborg-ized for decades. Pacemakers. Prosthetic limbs. Artificial hearts. Hearing aids. Implantable insulin pumps. Even the ubiquitous contact lens could be construed as an “artificial body part.” Whether one finds the idea terrifying or exciting, more and more of us depend on increasingly complex and varied bionic solutions. With nanotechnology and biomedical engineering innovations, those technologies grow ever smaller. And more sophisticated.

The tiniest medical devices of all

At the first Center for Electrochemical Engineering Workshop in 1991, the field of bioelectronics was formally defined as “the use of biological materials and biological architectures for information processing systems and new devices.” Researchers went on to describe the field, especially the subgenre of biomolecular electronics, as

the research and development of bio-inspired (i.e. self-assembly) inorganic and organic materials and of bio-inspired (i.e. massive parallelism) hardware architectures for the implementation of new information processing systems, sensors and actuators, and for molecular manufacturing down to the atomic scale.

If you’re not an expert in bioinformatics or some such field, don’t worry. “Molecular manufacturing down to the atomic scale” is the main takeaway. Using matter at its most granular, biomolecular engineers construct minuscule machines that process information. Itty bitty computers. And, when these wee computers are implanted into us, the theory goes, they’ll function with our body’s own nanomachines and energy systems. Because they’re “bio-inspired,” built with biomaterials and “biological architectures.” (What are biological architectures? Here’s an article that may clear it up. Or it may leave you even more confused.).

The problem of power for bioelectronic technology

Researchers and engineers already possess most of the constituent technologies needed, but major barriers remain. Such as figuring out how to power bioelectric implants. Because they’re designed to go into small spaces for long periods of time, internal batteries are less than ideal. If you’re not going to power the device from inside, the only other option is to power it from without. As it turns out, this is really hard to do. So far, viable biomedical engineering solutions have proven difficult, though progress has been made.

Bioelectronic disco?

The most promising solution to power bioelectric implants: wireless juicing with “near-infrared-ray (nIR) irradiation.” As a Nanowerk article explains, this involves a “flashing light” which can “penetrate into human tissue” as much as 10 cm deep. The bioelectronic technology absorbs this flashing nIR and experiences “temperature fluctuations” as a result. Apparently, these rapid changes in temperature produce “voltage/current pulses” that a team at Xi’an Jiaotong University has used to successfully stimulate the sciatic nerve of a frog as well as a rat heart.

While the team’s stimulation of rodent and amphibian nerves is certainly impressive, one can’t help but imagine a future of strobe-lit citizens crowding onto subways or sitting down for dinner in upscale restaurants, their implants gyrating to the rhythm of incoming radiation.

Electricity on a plate

In another development, a Stanford team sent an electrical current through a “flat plate adorned with a specially designed…conductive material.” With this plate — measuring 6 cm on each side — mounted on a hapless rabbit, they powered a rice-sized pacemaker in the bunny’s heart. Again, impressive, but more progress is needed. Even if other constraints with the plate-powering system were overcome, the appearance would solicit plenty of objections. Assuming I needed a tiny stimulator in the parietal region of my frontal lobe, I don’t know that I’d be thrilled to have a metal square fastened to my forehead. Then again, depending on my ailment, the relief just might justify the Frankensteinian aesthetic. Perhaps such skull plates might spawn a new fashion trend. Medi-goth, anyone? Biomedical engineering researchers continue to probe this avenue for more workable bioelectronic technology power sources. Let’s continue to watch their progress.

Blood, sweat, and tears power bioelectronic technology

Human bodies produce energy, and another avenue of research aims to harness it to power devices. We burn 2000-3000 calories per day; we’d need only to tap a tiny fraction of that to run a small implant.

Turns out, our bodily fluids contain a lot of energy for the taking. Enzymatic biofuel cells (EFCs) are already undergoing animal tests for their ability to metabolize energy-rich molecules for electricity generation. Via oxidation, the enzymes in the EFC force electrons into an electrode, which generates a small current. Plasma (the colorless, liquid component of blood) contains dissolved glucose, which many EFCs have been designed to use. Sweat contains lactate, which can power EFCs, but most of us don’t sweat continuously. So, that avenue may fizzle. Tears, however, contain a cocktail of energy-rich molecules —and our eyes produce them constantly in minute amounts. Already, bioengineers at the University of Utah have developed an electrode-containing contact lens that “maintained a power output of over one microwatt for three hours” when exposed to “a synthetic tear solution.”

Kinetic energy and piezoelectric materials

In addition to molecular energy contained in our fluids, we produce kinetic energy whenever we move. Even our internal organs produce enough motion that a group of Chinese and American researchers succeeded in harvesting a microwatt of power from “the beating hearts, lungs and diaphragms of (sedated) cows and sheep.” The mechanism used? Each slumbering beast had an “ultra-thin piezoelectric material” attached to the respective organ of study.

Piezoelectric (the Greek piezo means to squeeze or press) materials generate a charge when placed under stress. How? Such materials have an atomic lattice structure. Normally, the symmetrical structure of the lattice results in an energetic equilibrium. No difference in potential, thus, no electricity generation. However, when a force deforms the lattice — piezo — a difference in electrical potential emerges. An electrical charge.

In another experiment, researchers lined shoes with “an elastomer-based piezoelectric fabric.” They powered thirty LED lights from the energy generated by walking. The same group charged a lithium-ion battery by moving a shirt that had piezoelectric fabric applied to it.

Though their application to biomedicine is relatively new, piezoelectric materials have long been used in a number of industrial applications, from optics to motors to robotics. Typically, they reside in a fixed location in crystal form, creating an electrical charge when mechanically stimulated. In addition to their industrial utility, researchers have tried to scale piezoelectric technologies for macro power generation. These efforts have not been successful. Piezoelectric phenomena, it seems, operate under energetic size constraints. Which is fine for developers of bioelectronic implants.

Theoretically, then, nothing prevents us from powering our bioelectric implants with hi-tech fabric attached to our organs. Or piezoelectric clothing that somehow — and here lies the big knowledge gap — transmits electricity to the insides of our bodies. One way or another, piezoelectric materials will almost certainly have prominent applications in the coming bioelectronic revolution.

Google and GlaxoSmithKline bet on bioelectric implants

British pharmaceutical giant GlaxoSmithKline has joined forces with Google’s life sciences division, Verily. Their joint company, Galvani, will operate independently from both Google and GSK, and will focus solely on bioelectronic medicine and bioelectric implants. Galvani will explore the role of nerve signals in various health disorders. And how bioelectronic technology can modulate those signals. As the only pharma company with a biomedical engineering division devoted to bioelectronic technology, GSK is hoping to get far ahead of the pack by the time these tiny implants become mainstream.

Biomedical engineering will continue to advance

With such attention and resources behind the devolopment of bioelectric implants, we can expect even more breakthroughs. Each of the barriers to functional bioelectronic devices can be individually solved, given enough research. Power sources. Interfaces between bioelectric implants and the targeted nerves. Durable, non-degrading materials. Sufficiently sophisticated computers within bioelectronic technologies to read and process nerve signals and adjust output accordingly. These are major biomedical engineering challenges. However, in the scope of human invention, they’re far from insurmountable.

If, in the future, we’ve got these small medical devices inside of us, assisting our bodies with control of function, does that make us cyborgs? Invisible cyborgs, perhaps, because we’d lack the external post-apocalyptic cyborg accouterments of pop film. Does it really matter? Probably not. It’s fun to think about, however. Philosophical questions abound. Such as, for example, if we systematically add one piece of electromechanical equipment after another to modify our bodies, at what point do we stop being human and become mechanical? Or are we still human, even after every component of us has been replaced? Fascinating thought experiments. For now, however, if tiny medical devices can signal our nerves and help us reverse neurological disorders, we’ve accomplished a very good thing. Biomedical engineering research has already produced a plethora of technological marvels. No doubt it will continue to do so.