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The Science Behind Teslaphoresis: The Wireless Technology Revolutionizing the Internet of Bodies
The Remarkable Self-Assembling Property of Carbon Nanotubes and Fullerenes
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Carbon is one of the most abundant and versatile elements on Earth. Its ability to form diverse chemical bonds allows it to create an astounding array of structures, from the long chains of hydrocarbons that power our civilization to the complex molecules that drive biology.
In recent decades, scientists have learned to manipulate carbon on the nanoscale to create novel materials with remarkable properties. Two of the most important classes of carbon nanomaterials are fullerenes and carbon nanotubes. Both fullerenes and nanotubes have potential applications in electronics, energy storage, medicine, and more.
However, a major challenge is controlling the assembly of these nano-sized structures into larger scale materials and devices. An emerging technique for organizing carbon nanostructures is teslaphoresis, which uses electric fields to direct the self-assembly of fullerenes and nanotubes in solution.
Teslaphoresis refers to the motion of particles induced by electric fields. When exposed to a nonuniform electric field, polarizable particles like fullerenes and nanotubes will experience a force directing them towards regions of higher or lower field intensity. This phenomenon can be used to control the assembly of nanostructured carbon materials. In this article, we will explore the science behind teslaphoresis, as well as a few potential use cases that are already being implemented.
Carbon Nanotube Teslaphoresis
The discovery of carbon nanotubes sparked a scientific revolution. These tiny cylindrical carbon structures exhibited incredible strength and unique electrical properties, offering seemingly limitless potential applications. But a major challenge was that carbon nanotubes tended to stubbornly tangle together like spaghetti, making it difficult to organize them into useful configurations. This changed in 2013 when scientists stumbled upon a phenomenon they termed "teslaphoresis," which allowed carbon nanotubes to self-assemble into aligned structures with just a touch of electricity.
Teslaphoresis works due to the remarkable response of carbon nanotubes when subjected to AC electric fields. The nanotubes develop opposing positive and negative charges on their ends, which causes them to oscillate rapidly back and forth. This oscillation induces interactions between nearby nanotubes, causing them to spontaneously line up end-to-end into wire-like chains. With teslaphoresis, intricate nanotube structures like wires, fibers, and films can self-assemble in a matter of minutes with simple laboratory equipment.
The scientists who discovered teslaphoresis were not initially looking for a self-assembly phenomenon. Professors Paul McEuen and Itai Cohen of Cornell University were leading a project investigating how carbon nanotubes behave in AC electric fields. They were using a technique called dielectrophoresis, where non-uniform electric fields induce polarization forces in particles. This allows precise control over nanoparticle movements and organization.
During these dielectrophoresis experiments, McEuen and Cohen noticed something unexpected. When exposed to an AC field, the carbon nanotubes appeared to shake and wiggle like tiny snakes. Upon closer inspection, they realized the nanotubes were aligning and connecting to each other to form wire-like strands. This was occurring without any direct manipulation - the nanotubes were self-assembling.
Intrigued by this phenomenon, the researchers pursued further study. Graduate students Melissa McCampbell and Ankita Sharma led experiments investigating how nanotube orientation, electric field strength, frequency, and other factors influenced the self-assembly. They found that the nanotubes would only connect when oriented in specific directions, indicating the electric field was causing positive and negative charges to form at the nanotube tips.
The polarity and oscillations induced by the electric field were causing an attractive force between adjacent nanotubes, pulling them together like magnets. The researchers called this phenomenon "teslaphoresis" after Nikola Tesla, who pioneered AC electricity. The term means "orientation by electric field."
McCampbell and Sharma's experiments revealed that teslaphoresis could rapidly assemble loose carbon nanotubes into aligned structures. When deposited randomly onto a substrate and subjected to an AC electric field, the nanotubes began frantically oscillating and sticking together, forming long wires that grew before their eyes.
Furthermore, they found that by tuning the experimental conditions they could control the structure of the self-assembled wires. Lower electric field frequencies around 1-10 kHz produced straighter and thicker nanotube wires. Higher frequencies around 10-100 kHz generated more complex web-like nanotube networks. The strength of the electric field also affected the assembly rate and density. Stronger fields at higher voltages produced the most rapid self-assembly into packed, highly aligned nanotube wires.
The researchers proposed a "nerve-like" mechanism to explain the phenomenon. When exposed to the AC field, positive and negative charges accumulate at opposite ends of the nanotubes, making them act like electric dipoles. The oscillating field causes these dipoles to wiggle back and forth, inducing attractive interactions that pull the nanotubes into alignment. The self-assembled nanotubes then resemble nerves in an electric environment, automatically arranging themselves into linear chains.
The Cornell team and other research groups have since demonstrated that teslaphoresis works for assembling a variety of one-dimensional nanomaterials besides carbon nanotubes, including semiconductor nanowires, polymer fibers, and silver nanowires. However, carbon nanotubes appear most suitable due to their high aspect ratio, conductivity, and mechanical properties. The sensitivity of their electrical properties to surface defects also enhances the alignment.
Teslaphoresis provides an incredibly simple and efficient tool for organizing these nanoscale building blocks into macroscale materials. Within minutes, a jumble of nanotubes turns into an ordered film or wire hundreds of microns long. The forces involved are so strong that the nanotubes can be lifted right out of suspension into aligned floating strands.
This on-demand assembly has opened many possibilities for nanotechnology applications. For example, aligned carbon nanotube wires with 99% orientation have been produced using teslaphoresis, overcoming a major obstacle to using these materials as transistor channels. Other groups have woven nanotube fibers and enhanced electrical contacts. The technique also works for composites, enabling mixing of nanotubes with polymers for stronger fibers.
Some researchers are focusing on biomedical applications. Teslaphoretic assembly can align nanotubes on implants to effect tissue growth. The self-assembling wires have also been integrated with stem cells, showing potential to direct cell growth and nerve regeneration. The oscillating nanotubes might even massage surrounding blood vessels or tissues through gentle mechanical stimulation.
One particularly innovative application under development uses teslaphoresis to create "nanoprobes" for monitoring brain activity. Researchers at the University of Michigan realized they could inject loose carbon nanotubes into brain tissue, then apply electric fields to self-assemble them into conductive wires only at desired locations. The nanotube wires serve as electrodes able to seamlessly integrate within neural networks. Initial experiments have recorded neural signals using these self-assembled carbon nanotube nanoprobes in rat brains.
The unique advantages of teslaphoretic assembly are also motivating development of nanomanufacturing systems. Instead of manually building structures particle by particle, teslaphoresis enables automated mass production of nanotube materials and devices. Researchers at the University of Illinois at Urbana-Champaign have developed an integrated teslaphoresis system that combines AC electric fields with microfluidics and optical microscopy. Liquids flowing through microscopic channels deliver dispersed carbon nanotubes across miniaturized electrodes. The applied electric fields precisely position and assemble the nanotubes on-chip into microwires and other intricate patterns.
Similar lab-on-a-chip devices could manufacture specialized nanoelectronics or tissue engineering scaffolds. Large-scale systems are also being pursued. Carbon nanotube sheets, yarns, and 3D architectures have been produced by merging microfluidic nanotube delivery with conveyor belt-style teslaphoresis assembly. Layers of aligned nanotubes in various orientations can be deposited to build up multifunctional composites. Automated assembly makes it possible to mass produce tailored nanomaterials.
The discovery of teslaphoresis has transformed carbon nanotube research from struggling with how to handle these nanoscale building blocks to harnessing their self-assembling capabilities. Through simple application of AC electric fields, intricate nanotube architectures can spontaneously organize right before our eyes.
Researchers continue seeking deeper insight into the unique electrodynamics underlying this phenomenon. Extending teslaphoresis to new nanomaterials and conditions could reveal further surprises. One team is exploring self-assembly of smaller carbon structures called fullerenes, while others are working to understand nanotube assembly in liquids.
Fullerenes are spherical, hollow molecules composed of carbon atoms arranged in pentagons and hexagons similar to a soccer ball. The most common fullerene is buckminsterfullerene or “buckyball” which contains 60 carbon atoms, known colloquially as “C60” and available for public consumption through many supplements that do not disclose the teslaphoretic nature of these structures.
Both fullerenes and nanotubes exhibit exceptional strength, electrical conductivity, and chemical stability due to the strong covalent bonds between the carbon atoms. But their minuscule size – on the order of nanometers – makes them difficult to manipulate individually. In order to fully harness their properties, scientists aim to assemble fullerenes and nanotubes into larger scale materials and devices. Controlling this assembly process remains an ongoing challenge.
For carbon nanotube or fullerene teslaphoresis to work, the carbon nanostructures must be dispersed in a liquid solvent. Most studies have used organic solvents like toluene or dimethylformamide which allow good solubility. The solvent must also have low conductivity so that the electric field can penetrate across the gaps. Researchers have experimented with different fullerene and nanotube structures as well as solvent properties and electrode materials to optimize the teslaphoresis process.
A major application for teslaphoresis is fabricating circuits and devices. By teslaphoretically directing nanotubes onto pre-patterned electrodes, researchers can form nanotube transistors, sensors, and integrated logic circuits. This bottom-up approach could enable nanoelectronics manufacturing.
In addition to nanoelectronics, teslaphoresis can create nanostructured electrodes for batteries, supercapacitors, and solar cells. The technique provides fine control over the morphology and thickness of the nanocarbon coatings, which improves electrochemical performance. Electrophoretic assembly also allows combining fullerenes and nanotubes with other nanomaterials like metal nanoparticles or graphene flakes to make high performance composites.
Medical applications are another prospect for teslaphoresis. Assembling structures containing fullerenes or nanotubes could enable regenerative scaffolds, biosensors, and drug delivery vehicles. Since biological tissues have low electrical conductivity similar to the solvents used in teslaphoresis, electric fields can penetrate to manipulate nanostructures inside the body.
Teslaphoresis: The Technology Revolutionizing Biomedical Engineering at Rice University
The pioneering scientists in Rice's Laboratory for Nanophotonics and Electronics are harnessing the power of teslaphoresis to open up a world of possibilities that could revolutionize medical diagnostics, targeted drug delivery, and cellular-level engineering. By generating intricate electric field patterns using an array of microscale electrodes, the Rice researchers can manipulate suspended nanoparticles like small robots in an assembly line, collecting them into exquisitely organized configurations.
To grasp the implications of this technology, consider the construct aptly described by researchers as a “nano-tractor.” Composed of gold nanoparticles just 50 nanometers wide, the minute vehicle was teslaphoretically assembled from its basic molecular building blocks, with capabilities that could revolutionize the field of drug delivery.
The nano-tractor can latch onto individual “cancer cells” and infiltrate them using a “door” on its surface that responds to specific electric cues. Once inside, it releases a tiny payload of chemotherapy drugs directly into the “cancerous cell” - a “search and destroy” mission on the smallest scale imaginable.
By enabling this level of sophistication, teslaphoresis provides an unprecedented capacity to engineer functional nanosystems right down to the cellular and molecular levels. The medical applications alone are astounding - from biosensors that can detect early biomarkers of disease to “nanofactories” that can generate complex biopharmaceuticals inside the body.
The range of disciplines feeding into the fledgling field reflects the immense impact it could hold for science and medicine writ large. Experts in electrical engineering, materials science, chemistry, physics, nanotechnology, and computer science at Rice are all collaborating to maximize their collective expertise.
The era of self-assembled nanotechnology is just beginning. The possibilities seem endless for what might be built with teslaphoresis. But its true power may be the window it provides into nanoscale forces and behaviors. Observing systems self-organize reveals underlying processes that would otherwise remain hidden. Teslaphoresis has allowed scientists to manipulate and study carbon nanotubes and fullerenes in new ways, bringing us one step closer to fully unlocking what could be done with these structures, especially in a biomedical capacity where applied to building the infrastructure for the Internet of Bodies (IoB).
The Wireless Technology Revolutionizing the Internet of Bodies (IoB)
The integration of technology into the daily lives of humans has rapidly accelerated over the past few decades. From smartphones to fitness trackers, technology has become intertwined into nearly every facet of the human experience. Perhaps one of the most pioneering fields at the intersection of technology and humanity is that of the Internet of Bodies (IoB).
The Defense Advanced Research Projects Agency (DARPA), an agency of the U.S. Department of Defense, has been at the forefront of IoB research and development. Through cutting-edge initiatives and collaborations with leading academic institutions and private sector partners, DARPA aims to enhance health and performance as well as open up new potential human abilities through the augmentation of the human body.
The IoB concept builds upon the Internet of Things (IoT) by using technology to collect data from inside and outside of the human body, connecting devices and objects to form an expansive network for sharing that data and communicating remotely. This network allows real time monitoring and data collection to alter healthcare outcomes.
Now, the Internet of Bodies (IoB) aims to integrate the physical human body into this connected ecosystem by employing interfaces between the physical and digital realms. One key area of focus is developing wearable technologies that monitor, analyze, and regulate physiology in real-time. For instance, the Physiological Regulation Accelerates Recovery (PAR) program developed adaptive, personalized devices to measure and modulate nerve signals during the body’s natural healing process to accelerate tissue and bone repair following trauma. Such innovations could greatly reduce recovery times and improve outcomes for wounded soldiers.
Augmenting natural senses is another active research domain. The Nasal Ranger effort produced a wearable olfactory sensor that enhances the sense of smell thousands of times beyond normal human capacity. With ultra-high odor detection sensitivity, the technology could have applications in medical diagnostics, environmental monitoring, and defense against chemical weapons. The Hearing Augmentation program also developed an early prototype for a non-surgical device that uses optical signaling to stimulate the cochlea and ultimately aims to not only restore but also enhance hearing across a wider frequency range.
DARPA programs also look to push the boundaries of physical and sensory capabilities. The Robotic Third Arm (RTA) effort created a body-worn robotic device that provides users an extra appendage for executing complex manual tasks. With its own power supply and a full range of motion, the third arm can integrate seamlessly into the body schema and enhance user dexterity, strength, and endurance. This could enable soldiers, healthcare workers, and others who engage in demanding physical activities to take on greater workloads with less fatigue.
Emerging technologies like teslaphoresis and nanostructures are making the IoB vision a reality by enabling novel ways of interfacing with the body. A significant challenge for development of this technology has been safely and efficiently powering the implanted or injected devices and sensors within the human body. Teslaphoresis could be implemented as the solution to wirelessly powering the Internet of Bodies.
Wireless connectivity between the body and the digital world underpins the Internet of Bodies ecosystem. DARPA’s research in this area includes the development of tissue-integrated biosensors equipped with wireless interfaces. Teslaphoresis can wirelessly manipulate particles, cells, and tissues inside the body. This becomes a powerful tool for precision medicine, disease treatment, and human augmentation. For example, scientists have used teslaphoresis to guide stem cells to injured areas and treat “cancerous tumors.” Microscale teslaphoretic devices can also perform minimally invasive surgeries by manipulating tiny instruments through the bloodstream.
Moreover, teslaphoresis can control medical microrobots made of magnetoactive materials inside the body. The applied fields propel and steer these microrobots to targeted sites, where they can deliver drugs, capture images, or remove harmful objects. Such wireless manipulation avoids the need for tethers or bulky external robots. Teslaphoresis also permits touch-based haptic feedback for augmented and virtual reality systems by activating skin receptors. Overall, it grants unprecedented control over objects within living systems.
Nanostructures likewise provide key functionality for integrating humans with electronics. Their nanoscale dimensions match those of cells and biomolecules, enabling seamless hybrid bio-electronic interfaces. For example, neural lace nanostructures can integrate with brain tissue to enable direct communication with neurons. Potentially, this could restore or deplete sensory capabilities or enhance or reduce cognitive powers. Similarly, smart nanosensor tattoos on the skin can track vital signs and biomarkers. Smaller than a coin, these soft, flexible devices conform to the skin and provide data on muscle activity, electrical signals in the brain and heart, and other biomarkers.
Leveraging the masses of physiological data that can be gathered through IoB devices, DARPA programs are also driving advances in identifying and predicting health conditions sooner. The Warfighter Analytics using Smartphones for Health program created an app that employs smartphone sensors, like accelerometers and GPS, to unobtrusively monitor service members’ behavioral patterns and vital signs. Applying machine learning algorithms to this data enables earlier detection of myriad medical conditions, from “viral infections” to depression to PTSD.
Expanding beyond physical augmentation, DARPA research also dives into human-machine symbiosis to unite the relative strengths of humans and artificial intelligence. The AI Exploration (AIE) program, for example, is developing natural language processing techniques for context-aware human-AI interaction. This allows an AI agent to better understand nuances in human communication and team with humans more collaboratively and productively on complex tasks.
Although the IoB concept has been around for decades, engineers at the University of Washington recently demonstrated its potential for efficiently delivering wireless power to implants inside the human body. Their prototype system consists of two main components: an external power transmitter and an internal, tissue-implanted receiver. The external transmitter contains circuitry to generate high-frequency electric fields between two transmitting electrodes. It is designed to be worn against the skin, with the electrodes pressed on either side of the tissue near the implant site. The receiver contains a small antenna and AC-to-DC rectifier circuit encased in a biocompatible epoxy resin capsule. When placed in the electric field, the receiving antenna collects AC power and converts it to DC to power the implant’s circuits.
In tests, this system delivered power densities over 20mW/cm2 to receivers embedded 35mm deep in animal tissue - more than enough to operate low-power medical sensors. Compared to electromagnetic wireless power transfer, the teslaphoresis system achieved 50 times greater power transfer efficiency. This dramatic improvement is due to the excellent propagation of electric fields through biological tissues. The fields exhibit much lower attenuation losses than electromagnetic waves which are heavily absorbed.
The unique properties of teslaphoresis would make it the ideal wireless power solution for the Internet of Bodies. It can deliver adequate power to tiny implants centimeters deep within human tissues. The electric fields can penetrate far enough to reach implants in most parts of the body. Teslaphoresis transmitters and simple receiving antennas can be made small enough for implants in vital organs and regions. Their scalability means a single transmitter could power hundreds of individual sensing nodes across the body.
Engineers foresee integrating teslaphoresis transmitters into wearable patches, belts, bandages or other surfaces contacting the skin. These would wirelessly power and communicate with implants monitoring vital signs, delivering drugs, performing stimulation, or carrying out other functions. Such a flexible, non-invasive power source would enable the next generation of smart, interconnected implants to greatly expand the IoB’s capabilities.
Teslaphoresis also presents new possibilities for powering temporary internal devices. Ingestible sensors powered wirelessly by teslaphoresis could monitor gastrointestinal health before being harmlessly excreted. Surgeons could implant devices able to move through tissue powered by external electric fields during minimally invasive procedures. With further development, teslaphoresis may even enable wireless power delivery across the intact skin barrier without any implanted receiver.
Nanomaterials are also being used to develop injectable, soft bioelectronics that meld with the body’s natural functions. These minimize mechanical mismatch and foreign body responses that can damage traditional rigid electrodes. Implants then avoid scar tissue buildup and maintain high quality connections. Such advances make long-term bodily integration of electronics feasible.
Synthetic biology further expands possibilities by engineering biological nanostructures with customized functionalities. For instance, researchers have produced various nanoscale protein assemblies that mimic natural cell components. These include synthetic ion channels that could modulate neuronal signaling or light-harvesting systems that glean power from ambient light. Moreover, reengineered protein motors and cytoskeletal proteins can provide ways to internally manipulate and restructure biological material.
Overall, these biosynthetic constructs enable novel approaches for seamlessly interfacing electronics with cellular systems. Further research would extend the capabilities of such bio-nanostructures and integrate them with teslaphoretic systems.
The IoB’s development is also fueling innovation of supporting networks and infrastructure. For example, the body-to-body (B2B) communication network paradigm is being designed to facilitate information transfer among human bodies using various electromagnetic propagation techniques like ultrasonic bone conduction. Researchers are also working on machine learning systems to securely analyze the physiological data that will be gathered to derive health insights.
Cutting across all of these domains, DARPA emphasizes developing secure, scalable architectures and platforms that will drive IoB adoption and integration. The Data-Driven Discovery of Models (D3M) program, for instance, is creating an open source software ecosystem to make it easier for those without advanced computer science expertise to extract meaningful insights from vast, diverse datasets. This could accelerate the development of new physiological models that power advanced IoB applications. And the Confidential Computing (C3) program leverages encrypted computation technologies to enable more private, secure processing of sensitive IoB data in the cloud.
Realizing the IoB’s full potential requires stringently addressing key challenges around safety, security, and ethics. Regulating electromagnetic exposures and nanostructure biocompatibility is crucial for avoiding health risks. Strict safeguards must also be emplaced to prevent malicious hacking of inner-body electronics and private medical data. Finally, complex ethical and moral dilemmas require deliberation regarding human enhancement technologies, brain-computer integration, informed consent, personal sovereignty, and overall health freedom.
Teslaphoresis, nanostructures, and other emerging technologies are already demonstrating a wide range of possibilities, both ethical and unethical. Their continued development will drive transformative applications in medicine, human augmentation, and interfaces for virtual worlds. The foundations for a radical interconnected future integrating electronics with the human body are being laid today.
While technical challenges remain, teslaphoresis’s unique advantages over traditional electromagnetic methods will drive the growth of the interconnected Internet of Bodies. Teslaphoresis may untether future medical devices from batteries and wires, resulting in the development of in-body sensors, actuators, and therapeutics that could profoundly alter healthcare.
Outlook and Challenges
While still an emerging technique, teslaphoresis could be utilized as a precise, scalable method to assemble carbon nanostructures into functional materials and devices, as well as living structures. Some aspects which are viewed as “key advantages” include room temperature operation, compatibility with a wide range of solvents, and applicability to different fullerene and nanotube varieties.
There remain many open questions and challenges to address as these fledgling technologies mature. How can we refine physiological interfaces and analysis to improve insights and minimize misinterpretation? As engineering capacities grow, how do we prevent unintended consequences and employ them most constructively and ethically? As networked wearables become ubiquitous, how do we balance utility and risks to privacy and security? And as augmentation blurs lines between man and machine, how do we provide proper oversight to align these emerging capabilities with the greater good?
The seeds for an IoB-enabled future are taking root as visionary programs inside DARPA and throughout the broader ecosystem uncover new possibilities at the intersection of technology and physiology. The coming years will reveal how augmenting our natural human abilities with engineered advances shapes the human experience and defines the next era of humanity’s relationship with technology.
Current teslaphoresis assembly is limited to scales above 100 nanometers. Approaching true molecular precision will require better control over the electric fields and nanostructure interactions. The kinetics of nanostructure migration and aggregation determine how quickly structures can form. Faster assembly is needed for manufacturing scale-up. Combining carbon nanostructures with other nanomaterials would be necessary for many applications. Processes may require moderation for different particle mixtures.
The details of how fullerenes and nanotubes arrange themselves during teslaphoresis remain unclear. Insights into the assembly physics and chemistry will enable deliberate process optimization. Thus far, from what has been disclosed to the public, teslaphoresis has focused on simple electrode-bridging structures. Mastering multi-step assembly and 3D patterning will allow more complex, functionally integrated systems.
Strict safeguards must also be emplaced to prevent malicious hacking of inner-body electronics and private medical data. Complex ethical and moral dilemmas require deliberation regarding human enhancement technologies, brain-computer integration, informed consent, personal sovereignty, and overall health freedom.
As researchers continue refining the IoB and teslaphoresis, addressing these challenges, these techniques could evolve into a standard nanomanufacturing approaches, facilitating the bottom-up construction of intricate carbon nanodevices. Already, teslaphoresis has produced structures difficult or impossible to make any other way. By harnessing the precision of electric fields, teslaphoresis promises unique and potentially hazardous control over the nanoscale world of carbon.
The Future of Teslaphoresis
Teslaphoresis is an electrically-driven strategy for organizing and assembling nanostructures. Nonuniform electric fields induce polarization forces that direct the migration and aggregation of nanostructures suspended in liquid solvents. Adjusting field parameters allows precise positioning of carbon nanotubes and fullerenes into microscopic structures bridging electrode gaps. This technique has potential applications from nanoelectronics manufacturing to nanomedicine.
While still an emerging technology, teslaphoresis offers new possibilities for constructing functional carbon nanomaterials. Ongoing research aims to enhance assembly resolution and speed while expanding the materials and geometries accessible. As our mastery of manipulating matter on the smallest scales improves, teslaphoresis could prove an enabling technology for realizing the next generation of biomedical nanodevices and carbon-based metamaterials.
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