A new tool is emerging in the fight against antibiotic-resistant bacterial disease. Beyond the global efforts to limit overuse and abuse of antibiotic drugs, nanomedicine is finding additional ways to attack these superbugs. Nanoparticles, a million times smaller than a millimeter, are proving to be stable, easy to deliver, and readily incorporated into cells.
In recent work, a group of researchers at the University of Colorado, of which I am a member, have used nanoscale quantum dots—minuscule semiconductor particles with specific light-absorption properties—to kill drug-resistant superbugs without harming the surrounding healthy tissue.
[quote position="left" is_quote="true"]Superbugs, or bacteria that are resistant to more than one antibiotic drug kill more than 700,000 people each year.[/quote]
Once introduced into the body, the quantum dots do nothing until they are activated by having a light shined on them. Any visible light source (a lamp, room light or even sunlight) can be used for this. So far our research has focused on topical infections on the skin; deeper inside the body, brighter lights or more nanoparticles may be needed.
When activated by light, the quantum dots start generating electrons that attach to dissolved oxygen in the cells, creating radical ions. Those ions interrupt biochemical reactions which cells rely on for communication and basic life functions. In this way, we can target and kill very specific bacterial cells that cause illnesses.
The superbug threat
Antibiotics are used not just to treat active bacterial infections; they are also routinely given to patients undergoing surgery and to people with compromised immune systems from diseases like HIV and cancer.
Bacteria that are resistant to more than one antibiotic drug—or “superbugs,” as they are commonly called—infect more than 2 million Americans a year and kill 23,000 of them. Globally, they kill more than 700,000 people each year.
Projections by a United Kingdom government research panel suggest that, if unchecked, superbugs could kill more than 10 million people each year by 2050. That would far outpace all other major causes of death—including diabetes, cancer, diarrhea and road accidents. The economic cost is estimated at $100 trillion by 2050.
Focusing on a target
There are other nanoscale medicines for fighting infectious bacteria. When exposed to light, they heat up, killing all cells around them—not just the disease-causing ones. They, therefore, require special tools such as proteins or antibodies that selectively stick to desired cell types, to deliver them to very specific locations. That, in turn, requires the ability to accurately identify target cells.
Our method is an improvement because it allows more specific targeting of cells to be treated. Quantum dots with different sizes and electrical properties can help create different disruptive ions. That can allow doctors to choose disruptors to kill invading bacteria without harming nearby healthy tissue.
The activated quantum dots upset the balance of chemical processes, called “reduction-oxidation” (“redox” for short) in disease-causing bacteria in order to kill them.
Using this method and only a normal light bulb, we were able to eliminate a broad range of antibiotic-resistant bacteria. The bacteria were provided to us in the form of actual clinical samples from the University of Colorado School of Medicine. They included some of the most dangerous drug-resistant infections: methicillin-resistant Staphylococcus aureus; extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium; multi-drug-resistant Escherichia coli; and carbapenem-resistant Escherichia coli.
We were also able to make nanoparticles with different reactions to light, including having no response or even improving cellular reproduction. Increasing the growth of superbugs is not desirable, but this discovery may allow us encourage the growth of useful bacteria, such as in bioreactors, which can help manufacture of biofuels and antibiotic drugs.
Taking the next steps
So far our work has been in test tubes in controlled labs; our next step is to study this technique in animals. If successful, this technology could boost the fight against multi-drug-resistant bacteria in the short term and well out into the future.
It might, for example, spur the creation of a new class of light-activated drugs, lead to development of special fabrics with LED lights for phototherapy, and even form the basis of self-disinfecting surfaces and medical equipment.
And while the bacteria will continue to evolve to seek survival, our ability to control the specific reaction of the quantum dots, once activated, could let us move more quickly in this fight where defeat is not an option.
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Will your current friends still be with you after seven years?
Professor shares how many years a friendship must last before it'll become lifelong
Think of your best friend. How long have you known them? Growing up, children make friends and say they’ll be best friends forever. That’s where “BFF” came from, for crying out loud. But is the concept of the lifelong friend real? If so, how many years of friendship will have to bloom before a friendship goes the distance? Well, a Dutch study may have the answer to that last question.
Sociologist Gerald Mollenhorst and his team in the Netherlands did extensive research on friendships and made some interesting findings in his surveys and studies. Mollenhorst found that over half of your friendships will “shed” within seven years. However, the relationships that go past the seven-year mark tend to last. This led to the prevailing theory that most friendships lasting more than seven years would endure throughout a person’s lifetime.
In Mollenhorst’s findings, lifelong friendships seem to come down to one thing: reciprocal effort. The primary reason so many friendships form and fade within seven-year cycles has much to do with a person’s ages and life stages. A lot of people lose touch with elementary and high school friends because so many leave home to attend college. Work friends change when someone gets promoted or finds a better job in a different state. Some friends get married and have children, reducing one-on-one time together, and thus a friendship fades. It’s easy to lose friends, but naturally harder to keep them when you’re no longer in proximity.
Some people on Reddit even wonder if lifelong friendships are actually real or just a romanticized thought nowadays. However, older commenters showed that lifelong friendship is still possible:
“I met my friend on the first day of kindergarten. Maybe not the very first day, but within the first week. We were texting each other stupid memes just yesterday. This year we’ll both celebrate our 58th birthdays.”
“My oldest friend and I met when she was just 5 and I was 9. Next-door neighbors. We're now both over 60 and still talk weekly and visit at least twice a year.”
“I’m 55. I’ve just spent a weekend with friends I met 24 and 32 years ago respectively. I’m also still in touch with my penpal in the States. I was 15 when we started writing to each other.”
“My friends (3 of them) go back to my college days in my 20’s that I still talk to a minimum of once a week. I'm in my early 60s now.”
“We ebb and flow. Sometimes many years will pass as we go through different things and phases. Nobody gets buttsore if we aren’t in touch all the time. In our 50s we don’t try and argue or be petty like we did before. But I love them. I don’t need a weekly lunch to know that. I could make a call right now if I needed something. Same with them.”
Maintaining a friendship for life is never guaranteed, but there are ways, psychotherapists say, that can make a friendship last. It’s not easy, but for a friendship to last, both participants need to make room for patience and place greater weight on their similarities than on the differences that may develop over time. Along with that, it’s helpful to be tolerant of large distances and gaps of time between visits, too. It’s not easy, and it requires both people involved to be equally invested to keep the friendship alive and from becoming stagnant.
As tough as it sounds, it is still possible. You may be a fortunate person who can name several friends you’ve kept for over seven years or over seventy years. But if you’re not, every new friendship you make has the same chance and potential of being lifelong.