Sometimes our bodies need a lift. Hundreds of thousands of Americans depend on pacemakers — small devices that regulate the electrical impulses of the guts so as to keep it beating easily. But to scale back complications, researchers would really like to make these devices even smaller and fewer intrusive.
A team of researchers with the University of Chicago has developed a wireless device, powered by light, that might be implanted to control cardiovascular or neural activity within the body. The featherlight membranes, thinner than a human hair, might be inserted with minimally invasive surgery and contain no moving parts.
Published Feb. 21 in Nature, the outcomes could help reduce complications in heart surgery and offer latest horizons for future devices.
“The early experiments have been very successful, and we’re really hopeful concerning the future for this translational technology,” said Pengju Li, a graduate student on the University of Chicago and first creator on the paper.
‘A brand new frontier’
The laboratory of Prof. Bozhi Tian has been developing devices for years that may use technology just like solar cells to stimulate the body. Photovoltaics are attractive for this purpose because they wouldn’t have moving parts or wires that may break down or grow to be intrusive — especially useful in delicate tissues like the guts. And as an alternative of a battery, researchers simply implant a tiny optic fiber alongside to supply power.
But for one of the best results, the scientists needed to tweak the system to work for biological purposes, somewhat than how solar cells are frequently designed.
“In a solar cell, you need to collect as much sunlight as possible and move that energy along the cell regardless of what a part of the panel is struck,” explained Li. “But for this application, you need to find a way to shine a lightweight at a really localized area and activate only that one area.”
For instance, a typical heart therapy is referred to as cardiac resynchronization therapy, where different parts of the guts are brought back into sync with precisely timed charges. In current therapies, that is achieved with wires, which might have their very own complications.
Li and the team got down to create a photovoltaic material that might only activate exactly where the sunshine struck.
The eventual design they settled on has two layers of a silicon material referred to as P-type, which reply to light by creating electrical charge. The highest layer has many tiny holes — a condition referred to as nanoporosity — which boost the electrical performance and concentrate electricity without allowing it to spread.
The result’s a miniscule, flexible membrane, which might be inserted into the body via a tiny tube together with an optic fiber — a minimally invasive surgery. The optic fiber lights up in a precise pattern, which the membrane picks up and turns into electrical impulses.
The membrane is only a single micrometer thin — about 100 times smaller than the best human hair — and a couple of centimeters square. It weighs lower than one fiftieth of a gram; significantly lower than current state-of-the-art pacemakers, which weigh a minimum of five grams. “The more lightweight a tool is, the more comfortable it typically is for patients,” said Li.
This particular version of the device is supposed for temporary use. As an alternative of one other invasive surgery to remove the pacemaker, it simply dissolves over time right into a nontoxic compound referred to as silicic acid. Nevertheless, the researchers said that the devices might be engineered to last to different desired lifespans, depending on how long the guts stimulation is desired.
“This advancement is a game-changer in cardiac resynchronization therapy,” said Narutoshi Hibino, professor of surgery on the University of Chicago Medicine and co-corresponding creator on the study. “We’re on the cusp of a brand new frontier where bioelectronics can seamlessly integrate with the body’s natural functions.”
Light use
Though the primary trials were conducted with heart tissue, the team said the approach might be used for neuromodulation as well — stimulating nerves in movement disorders like Parkinson’s, for instance, or to treat chronic pain or other disorders. Li coined the term ‘photoelectroceuticals’ for the sphere.
Tian said the day after they first tried the pacemaker in trials with pig hearts, that are very just like those of humans, stays vivid in his memory. “I keep in mind that day since it worked within the very first trial,” he said. “It’s each a miraculous achievement and a reward for our extensive efforts.”
A screening method developed by Li to map the photoelectrochemical output of assorted silicon-based materials could even have uses elsewhere, Tian identified, equivalent to in fields like latest battery technologies, catalysts, or photovoltaic cells.
