One of the more unlikely premises for a movie was the idea behind the 1966 film Fantastic Voyage. A scientist who plays a crucial role in the Cold War is stricken by a blood clot, and his own invention—a way to shrink objects to microscopic size for only an hour—is applied to a submarine full of people who then travel through his bloodstream to save him.
Science fiction has a way of becoming reality, and while nobody has yet figured out how to shrink people and submarines, a recent New Yorker profile of the work of chemist James Tour and his colleagues describes microscopic light-powered jackhammers that can penetrate bacteria cell walls.
In the first place, living cells are fantastically complex machines in their own right, so there is nothing intrinsically new about tiny machines. The innovation claimed by Tour and his team is that they have developed a way to control the action of tiny jackhammer-like molecules by irradiating them with a specific wavelength of near-infrared light. The molecules have what are called plasmons in them. The details are complicated, but basically the plasmon acts like a kind of molecular tuning fork that resonates at one particular wavelength. When light of that wavelength hits the molecule, it absorbs a great deal of energy and begins to vibrate vigorously, punching a hole in the bacterial wall and initiating the bacteria's demise. And in contrast to shorter wavelengths of light in the visible range, near-infrared light can penetrate an inch or two into the body, allowing access to fairly deep regions under the skin.
So far, no human tests have been done. Some moth larvae in Tour's lab have been treated with molecular jackhammers to save them from a terrible death from MRSA bacteria, but that's about it so far. Years of testing with increasingly complicated organisms—mice, pigs, and so on—lies ahead before any practical applications to humans can be expected. And there may be some bump in the road ahead that will prevent this technology from finding any application in humans at all. But so far it looks promising, and I'm sure Prof. Tour will have no problem finding funding for more research, and commercial applications too if he's interested.
The article's author Dhruv Khullar mentions that some researchers are concerned about the inherent dangers of molecular machines. He describes the "gray-goo" problem posed by an early futurist, K. Eric Drexler, who speculated that if a nanomachine was programmed to turn every living thing into more of itself, it might infect the whole biosphere. This reminds me of what happened to some goldfish my mother bought us when we were kids, after giving in to our continual begging for them. The fish were fine for a while, but one morning we got up and instead of goldfish, there were just floating lumps of whitish gunk in the tank. She got rid of the aquarium soon after that, and we never had any more fish unless they were cooked first.
Tour's devices don't seem to pose such a hazard, because without the special near-IR wavelength of light shining on them, they don't do anything. So that seems to be a pretty safe way to control them, unless you start speculating about how you might sneak some molecular jackhammers into a victim's drink, and then take them into a room bathed with the requisite wavelength of near-IR light, which is invisible, of course. And there you go with another science-fiction suspense film.
It seems to me that activities such as Tour's are pretty harmless compared to, for instance, tinkering with existing coronaviruses with gain-of-function research. For whatever reason, nature has produced (or God has allowed, depending on your point of view) some really nasty viruses that use mechanical means to take over cells and turn them into virus factories, with the byproduct of making the host ill or dead. I was unable to locate the details, but someone once told me that the rabies virus is precisely designed with a kind of spear that penetrates neurons to infect them. So in developing his molecular jackhammers, Prof. Tour isn't inventing as much as he is co-opting a technique and powering it by other means, namely light waves. And arranging things so that the molecules can't do anything without external illumination is a nice fail-safe feature that allows the researcher to exert control.
This work is only one example of the discoveries scientists and engineers can make when provided with enough resources and cultural favor. Not every country in the world is hospitable to scientific research of this type. And it takes money and smart people, which are both limited resources. We should not take such activities for granted, because they don't happen automatically. It's easy to assume that medical technology will just keep on advancing on its own without anybody other than the researchers paying much attention.
But there is a big threat to all U. S.-government-funded research looming on the horizon. While the U. S. has never experienced a fiscal crisis such as the one that struck Germany in the early 1920s, nothing says we are immune from it. As interest rates rise and the population ages, two money sinks—interest on the national debt and entitlements such as Social Security and Medicare—threaten to take over the Federal budget and squeeze out just about everything else. While private funding has increasingly taken up the slack vacated by declining government support for research, it's hard to imagine a healthy private sector persisting if the government has gone bankrupt.
And such events are not that predictable. Neither major political party currently has the intestinal fortitude to address this issue with anything near the seriousness it deserves. As things stand, there is still enough research money available to support impressive efforts such as the things Prof. Tour and his group are doing. But if we are to see any practical benefits from it, there are years of work ahead, work that somebody has to do and somebody else has to pay for. Smart young people will have to decide that research is worth doing, and the public will have to decide that it's worth paying for, and worth having a fiscally sound government to pay for it. So far, it's all working, but whatever can't go on forever eventually has to stop.
Sources: The New Yorker of June 24, 2024 carried Dhruv Khullar's article "Small Wonder" on pp. 20-23. I also referred to a Rice University post on Prof. Tour's research at https://news.rice.edu/news/2023/molecular-jackhammers-good-vibrations-eradicate-cancer-cells
and Wikipedia articles on plasmons and molecular machines.
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