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The loss of cartilage—the gristly protein pads that keep bones from rubbing on each other in our joints—is as common as aging. As it disappears, everyday movements become painful, especially in hands, hips, and knees.
Cartilage doesn’t restore itself well because it contains no blood vessels to nourish it. When cartilage wears away, doctors usually try to stimulate new growth by scraping or drilling the adjacent bones, hoping that bleeding from the wounds will tell the remaining cartilage to grow.
Now scientists at the University of Connecticut have tried something new that seems to be working.
They started by making a tiny scaffold out of a nontoxic, biodegradable polymer called poly-L lactic acid (PLLA). The scaffold makes a place for cartilage cells and their building blocks, such as collagen, to collect.
The idea of using a scaffold to help cartilage self-regenerate isn’t new. But past attempts have produced no more than mediocre results because the scaffolds tend to break down under the stress of joints’ motion.
PLLA is different: it’s piezoelectric.
A piezoelectric material creates an electric current from the pressures and stresses of motion—and tiny electric currents are well-known to stimulate cell growth in the process of healing wounds and bone fractures.
The idea: the steady electric current produced by routine activities such as walking, squeezing, or kneeling would constantly stimulate the production of new cartilage, leaving a new pad behind when the scaffold finally dissolves.
When the researchers tested their idea on rabbits with bad knees, after a month the rabbits’ knees were growing a good crop of new cartilage. In contrast, rabbits implanted with scaffolds that weren’t piezoelectric showed little new growth.
The developers are planning tests on larger animals.
TRENDPOST: The healing effects of electricity and light inside the body (see “Tuning Up the Brain with Light,” 25 Jan 2022) are only beginning to be harnessed and present a growth area for researchers, developers, and entrepreneurs over at least the next two decades.