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Tiny, spherical “robots” could be the solution to the longstanding pharmaceutical dilemma of targeted drug delivery. A multinational team of researchers published a paper last week detailing a multistage system that they envision being used for the treatment of localized gastrointestinal diseases, including cancer.
Chemotherapy is one of best weapons we have for fighting cancer, but its side effects can be almost as bad as the disease itself. Unfortunately, in most chemotherapy treatments, only about 1% of the drug being administered actually reaches the tumor it’s meant to treat. That means current dosages are 100 times what they could be if the drugs were applied directly to the problem area.
While pharmaceutical research advanced by leaps and bounds in the 20th century, very little changed when it came to delivery. Whether injecting or ingesting the drugs, patients had to rely on their body’s natural systems for dispersal.
New technologies in the 21st century have made drug delivery the cutting-edge frontier. Because of the microscopic scales involved, it’s a world that sits at the intersection of cellular biology and engineering.
Previous advancements took place at the nanoscale, taking cues from the body’s own cells to find ways to make medications adhere to the specific tissues they target. This team has moved the focus back out one step to the microscale, creating 3D-printed vehicles to carry infinitesimal droplets of medication through the cut to their target, guided by magnetic fields.
Magnetism, 3D-Printing, and pH-Sensitive Encapsulation
Talk of nanotechnology and robots conjures to mind sci-fi imagery: invisibly tiny metallic spiders bearing equally tiny syringes, perhaps.
The actual “robots” we’re talking about are much simpler in design. They are, essentially, hollow plastic balls the size of a speck of dust, filled with medicine and a ferromagnetic substance that makes them responsive to magnetic fields. At the top is a grid of circular holes, each perhaps 10 or 20 micrometers in diameter, which allow them to be filled.
Yet, although the design would look trivial if scaled up to everyday sizes, the precision necessary to execute it at micrometer scales is a recent development. The team used a process called two-photon polymerization, which works a bit like resin-based home 3D printers, but with a twist.
Printing resin cures when it absorbs light in the ultraviolet spectrum. The “two-photon” version uses intersecting lasers at infrared wavelengths, which combine to produce the necessary energies only where they cross.
After printing these tiny spheres, the team filled them with neodymium-iron-boron particles and the drug payload, separated by a thin barrier. They then coated each sphere with a pH-responsive polymer layer that will hold up against stomach acid but dissolve in the slightly different chemical environment of the intestine.
A patient would injest a dose of these spheres, and doctors could then use electromagnetism to track the neodymium-iron-boron particles inside the spheres and, essentially, roll them around inside the patient to get them where they need to go. Then the coating would dissolve in the intestinal juices, and the medicine would escape through the holes only once it’s at its destination.
Microtechnology and Nanotechnology Working Together
The researchers describe their system as “multistage,” because targeting doesn’t end once the medicine escapes the microrobots. The second stage is the earlier nanoscale innovation mentioned above.
The drug payload proposed by the researchers is coated with natural cell membranes derived from blood platelets. The chemical structure of these membranes has been found to bind especially well to cancer cells, while being able to penetrate other types of tissue.
In other words, the 3D-printed microscale stage of the delivery system gets the drug to its destination, while the biomemetic nanoscale second stage keeps it there until it does its job.
While this technology appears extremely promising, it may be a while before it sees use in real human patients. The researchers tested their microrobots in the stomach and intestines of a dissected pig, but the technology hasn’t yet progressed to the point of an in vivo trial.
Also in Science News
AI Improves CRISPR’s ‘Molecular Scissors’ for Gene Modification
Genetic modification is another area in which modern technology has allowed for nanoscale breakthroughs. Here, however, there is a different problem: the complexity of protein geometry, which has historically forced scientists into a tedious process of trial and error.
CRISPR is a technology that repurposes the chemistry of bacterial immune systems, borrowing the “mechanical scissors” they use to snip out sections of viral DNA. Genetic researchers are constantly trying to improve on nature’s solutions, but modifying the enzymes in question produces unpredictable results once they’re applied to DNA. There are a lot of failures for every success.
Now, AI is helping to speed up that process by simulating how hypothetical enzymes will interact with DNA strands. In principle, that should allow researchers to reject solutions that are unlikely to function, without needing to go through the process of physically producing the enzymes to test them.
Satellites, Sensors on the Front Lines of the Battle Against Wildfires
Wildfire prevention has historically relied on networks of manned observation towers, but advancements in satellite technology are bringing the battle to space. Ground-based sensors also help, but can miss fires when the wind is blowing in the wrong direction.
The trouble with satellites is that if they’re too high up, they can’t catch small fires before they turn into big ones. Meanwhile, lower-orbiting satellites travel faster, meaning they’ll only catch a quick glimpse of a fire, then need to complete an orbit before they can provide an update.
The answer is going to be “constellations” of low-orbiting satellites working together and compiling time-lapse data on a fire as each passes over it in turn.
The Long Journey of Earth’s Largest Diamonds
Sometimes science is used to deepen our understanding of the planet we live on, and sometimes it’s just used to make people rich. Occasionally, it can do both things at once.
Geologists have made a breakthrough in understanding how the largest and rarest type of diamond — known as a CLIPPIR — occurs. Specifically, how they make it back to the surface, since it was already known that they form deep in the mantle, much further away from the surface from other types of diamond.
CLIPPIR diamonds can weigh up to thousands of carats and sell for tens of millions of dollars. Finding them, however, has been largely a matter of luck until now. But a group of geologists from Cape Town say that they’ve determined that they only form when iron-rich sea floor basalt gets subducted into the mantle. Since the resulting rocks are denser than the rest of the mantle, they only make it back to the surface if carried by mantle plumes — upward currents of superheated magma.
That combination of findings is of academic value to the scientific community, but might also help diamond-hunters narrow their search for the next CLIPPIR.
