This is one in a series presenting news on technology and innovation, made possible with generous support from the Lemelson Foundation.
Our ears and noses contain a special tissue that’s softer than bone but stiffer than muscle. Reshaping this tissue for medical reasons usually requires “cut-and-sew” surgery. Healing from that type of surgery can be painful and leave scars. Soon, however, surgeons may avoid these problems by using electricity instead of a scalpel.
The special tissue is cartilage (KAR-tih-lidj). It’s difficult to reshape because its inner structure is very strong. It always bounces back into its original shape. The body has different types of cartilage. The form in our ears and nose is less rigid than the type in our joints, tendons and spinal discs.
Brian Wong is a surgeon who works at the University of California, Irvine. He’s also a biomedical engineer. He uses engineering know-how to solve medical problems. A few years ago, Wong was looking for ways to fix a deformed nose without cutting and stitching.
The cartilage that separates the nostrils inside the nose is known as the septum. In some people, this tissue is off-center or crooked. Such a “deviated” septum can make breathing difficult. Some people might be born with the problem. A sports injury or other trauma might also alter the septum’s shape.
Traditional septum surgery is challenging. The area that needs fixing is hard to reach. The space is tiny. Cutting into cells with blades tends to damage or kill the cells, creating scar tissue. The healing can prove painful. And mistakes can be quite visible.
To avoid some of these problems, Wong had tried heating the cartilage with an infrared (Inn-fruh-RED) laser as a new way to reshape the septum without a scalpel. That’s less invasive than cutting into the nose with a knife. And it worked. But the heating still damaged cells. This procedure also was expensive.
Electric current to the rescue
So Wong’s team decided to try heating the cartilage with an electric current. They started by working with a sample of cartilage in a lab dish. The current indeed let Wong reshape the tissue — but with hardly any temperature increase.
That was a big surprise.
To figure out what was going on, Wong contacted Michael Hill. He’s a chemist at Occidental College in Los Angeles, Calif. Hill studies how electricity affects chemical processes. And when he learned that 75 percent of cartilage consists of water, he had a hunch that the water might explain what happened. An electric current can split water into two atoms of hydrogen and one atom of oxygen. Chemists call this process electrolysis (Ee-lek-TRAHL-uh-sihs).
Hill’s hunch turned out to be right. And here’s how that electrolysis softened the tissue. That cartilage in our ears and noses is weblike. Its fibers are made from a protein called collagen (KAHL-uh-jen). Electric bonds between the molecules hold those fibers together. The negatively and positively charged parts of the molecules glom together like the positive and negative poles of two magnets.
So pulling apart the collagen web is like pulling apart two magnets. “If you let go, the molecules snap back together, like the magnets would,” explains Hill. “The electric bonds give cartilage the ability to hold its shape. But if we can briefly turn off the bonds, we can change that shape.”
The energy to turn off those bonds came from splitting the water in cartilage. Exposing a small region of the tissue to an electric current created hydrogen atoms that were positively charged. They canceled out the tissue’s negatively charged molecules. And that broke apart the electric bonds to make the cartilage malleable, like Play-Doh.
Now a surgeon could reshape the tissue. As soon as that doctor turned off the current, the electric bonds would quickly reform. The tissue’s new shape also would become permanent.
Bend an ear
Hill and Wong first tested the process on the ear of a rabbit that had died. Their goal was to permanently bend the ear 90 degrees from its normal, upright shape. To do this, they made a 3-D image of the ear. Using special computer software that the researchers had developed, they analyzed that image and printed a 3-D mold of the new shape they wanted to give that ear.
Their software then showed them the best place in the ear to place two tiny needles. Pulsing an electric current through these needles softened the tissue there. The software also figured out how long to send the current pulsing through those needles.
While delivering the current, the researchers bent the softened tissue into the new shape and then held it in place with the 3-D mold. Turning off the electricity allowed the cartilage to harden. It then kept that new shape after the researchers removed the mold. The entire process took only a few minutes.
“The chemistry couldn’t be simpler,” Hill says. “Not so simple,” he notes, “was figuring out how to zoom in on the small region we want to treat.”
The researchers first described this process three years ago in the journal Angewandte Chemie: International Edition. (The first part of the journal’s name is German and means applied chemistry.)
It took much longer to develop the computer software and test the reshaping of cartilage in live rabbits. The process killed very few cartilage cells, which proved a big advantage over traditional surgery. Hill reported his team’s new test data this past April at the American Chemical Society spring annual meeting in Orlando, Fla.
Those animal tests were really important, says Taylor Lawson, who was not involved with the research. He works at Boston University, where he studies knee and hip cartilage.
“You want to avoid injuries around the needle-insertion site,” he says. “You also need to know how much voltage to apply for a desired new shape. And you have to learn how to limit the electric current to just the area of interest.”
These are some of the things the researchers will now test in larger animals. Eventually, Hill and Wong hope to extend their team’s tests to humans. First, they have to ensure the new method will be safe to use in people. New medical procedures require many rounds of tests. Some are known as clinical trials.
If approved for humans, the new technique might be used to fix a deviated septum and other nose problems. It also could adjust ears that stick out. (This would help kids who get teased about “Dumbo” ears, says Hill.)
Eyes on the future
Hill and Wong wonder if their molecular surgery might have even broader uses, such as fixing vision problems. If it also works in people, Hill and Wong think their technique could help millions of people who are nearsighted, farsighted or have trouble reading as they get older.
Eyeballs aren’t made of cartilage. But like cartilage, the transparent layer on top of the eyeball — the cornea (KOR-nee-uh) — is made from a web of collagen fibers. In nearsighted people, the eyeball has grown too long, so the cornea is overly curved. That makes far-away objects appear blurry. Flattening the cornea fixes this problem. And electrolysis may be one way to do this.
So far, working in a lab dish, the researchers have only tried the technique on a rabbit’s cornea. They printed a mold for a contact lens and then painted electrodes onto it. After they put the mold onto the cornea, the researchers applied an electric current. This succeeded in changing the cornea’s shape.
The researchers have yet to try this on living animals. That means it will take many years to assess whether it is safe enough for people. But if it is, it one day might replace glasses and contact lenses in those who choose to have the procedure. The researchers think their method might pose fewer risks and side effects for correcting vision problems than laser surgery now does. That surgery “shaves off” thin layers of the cornea, instead of reshaping its tissue.
Hill and Wong are also working toward their original goal. Wong hopes he can soon fix ear and nose problems in a five-minute, low-cost procedure that can be done in a doctor’s office without causing pain or scars.
Chemist Stefanie Sydlik, who was not involved in the work, thinks that is a realistic goal. She studies cartilage and other body tissues at Carnegie Mellon University in Pittsburgh, Penn. This new technique should have great potential, she says, if the researchers can prove that it’s safe.
“The science behind it is really cool because it’s such a simple concept,” Sydlik says. “You use the water inside your own tissue to create the energy for changing its shape.”
3-D Short for three-dimensional. This term is an adjective for something that has features that can be described in three dimensions — height, width and length.
atom The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.
biomedical engineer An expert who uses science and math to find solutions to problems in biology and medicine; for example, they might create medical devices such as artificial knees.
bond (in chemistry) A semi-permanent attachment between atoms — or groups of atoms — in a molecule. It’s formed by an attractive force between the participating atoms. Once bonded, the atoms will work as a unit. To separate the component atoms, energy must be supplied to the molecule as heat or some other type of radiation.
cartilage A type of strong connective tissue often found in joints, the nose and ear. In certain primitive fishes, such as sharks and rays, cartilage provides an internal structure — or skeleton — for their bodies.
cell The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall.
chemical A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.
chemistry The field of science that deals with the composition, structure and properties of substances and how they interact. Scientists use this knowledge to study unfamiliar substances, to reproduce large quantities of useful substances or to design and create new and useful substances.
clinical trial A research trial that involves people.
collagen A fibrous protein found in bones, cartilage, tendons and other connective tissues.
cornea The transparent front section of the eye. The shape of the cornea allows our eyes to bring objects at many distances into focus.
current (in electricity) The flow of electricity or the amount of charge moving through some material over a particular period of time.
degree (in geometry) A unit of measurement for angles. Each degree equals one three-hundred-and-sixtieth of the circumference of a circle.
develop To emerge or come into being, either naturally or through human intervention, such as by manufacturing.
deviated septum A medical condition where the nasal septum — a thin wall in the center of the nasal interior, separating the breathing passages on each side — has been moved, or deviated, toward one side. In severe cases, it can make it hard to breathe by reducing how much air can flow through the nose.
electric current A flow of electric charge — electricity — usually from the movement of negatively charged particles, called electrons.
electricity A flow of charge, usually from the movement of negatively charged particles, called electrons.
electrode A device that conducts electricity and is used to make contact with non-metal part of an electrical circuit, or that contacts something through which an electrical signal moves. (in electronics) Part of a semiconductor device (such as a transistor) that either releases or collects electrons or holes, or that can control their movement.
electrolysis The use of an electric current to separate chemicals in a solution. The current forces ions to move towards electrodes — either a cathode or anode — at either end of the system.
engineering The field of research that uses math and science to solve practical problems.
fiber Something whose shape resembles a thread or filament.
hydrogen The lightest element in the universe. As a gas, it is colorless, odorless and highly flammable. It’s made of a single proton (which serves as its nucleus) orbited by a single electron.
infrared A type of electromagnetic radiation invisible to the human eye. The name incorporates a Latin term and means “below red.” Infrared light has wavelengths longer than those visible to humans. Other invisible wavelengths include X-rays, radio waves and microwaves. Infrared light tends to record the heat signature of an object or environment.
invasive An adjective that refers to something that can invade some environment (such as an invasive species) or alter some environment (such as invasive medical procedures).
laser A device that generates an intense beam of coherent light of a single color. Lasers are used in drilling and cutting, alignment and guidance, in data storage and in surgery.
lens (in biology) A transparent part of the eye behind the colored iris that focuses incoming light onto the light-absorbing membrane at the back of the eyeball.
magnet A material that usually contains iron and whose atoms are arranged so they attract certain metals.
malleable Something whose shape can be altered, usually by hammering or otherwise deforming with pressure.
molecule An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).
muscle A type of tissue used to produce movement by contracting its cells, known as muscle fibers. Muscle is rich in protein, which is why predatory species seek prey containing lots of this tissue.
nearsighted An inability to focus anything that isn’t nearby. It’s due to an elongation of the eyeball. Many factors can contribute to this inappropriate elongation, and so the cause of nearsightedness is still under debate.
oxygen A gas that makes up about 21 percent of Earth's atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).
protein A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Among the better-known, stand-alone proteins are the hemoglobin (in blood) and the antibodies (also in blood) that attempt to fight infections. Medicines frequently work by latching onto proteins.
risk The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)
scalpel A type of special knife used to open the body, usually to perform surgery.
side effects Unintended problems or harm caused by a procedure or treatment.
software The mathematical instructions that direct a computer’s hardware, including its processor, to perform certain operations.
tendon A tissue in the body that connects muscle and bone.
tissue Made of cells, it is any of the distinct types of materials that make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues.
trauma (in medicine) An injury, often a fairly severe one. This term also can refer to a severely disturbing incident (such as witnessing a battlefield death) or memory.
voltage A force associated with an electric current that is measured in units known as volts. Power companies use high-voltage to move electric power over long distances.
Journal: B.M. Hunter et al. Controlled-potential electromechnical reshaping of cartilage. Angewandte Chemie: International Edition. Vol 55, April 2016, p. 5497. doi: 10.1002/anie.201600856.
Meeting: M.G. Hill et al. Electrochemical tissue reconstruction. Spring 2019 National Meeting, American Chemical Society. March 31-April 4, 2019. Orlando, Fla.