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.
Ultrasound of human baby.Image via 
IVF animated process.Image via 
A couple speaks with a fertility professional.Image via 
Love, Mom.Photo from Heidi Johnson 
A teen boy having a hard time. 
Hands hold a digital representation of the brain.Image via 
Mother and daughter work a puzzle.Image via 
Man and woman connect under the sunshine.Image via 
The obituary paints a comic, if bleak, picture. 
A Facebook post about the obituary.
Why do some folks use social media but don't engage?
Psychologist says people who never comment on social media share these 5 positive traits
For over 20 years, social media has developed into a staple in many people’s day-to-day lives. Whether it’s to keep in communication with friends and family, following the thoughts of celebrities, or watching cat videos while sipping your morning coffee, there seem to be two types of social media users: commenters and lurkers.
The term “lurker” sounds equally mysterious and insidious, with some social media users writing them off as non-participants at best or voyeurs at worst. However, mindfulness expert Lachlan Brown believes these non-commenters have some very psychologically positive and healthy traits. Let’s take a look at how each one of these traits could be beneficial and see how fruitful lurking might be even though it can drive content creators crazy.
1. Cautious about vulnerability
Consciously or not, making a post online or commenting on one puts you and your words out there. It’s a statement that everyone can see, even if it’s as simple as clicking “like.” Doing so opens yourself up to judgment, with all the good, bad, and potential misinterpretation that comes with it. Non-commenters would rather not open themselves up to that.
These silent users are connected to a concept of self-protection by simply not engaging. By just scrolling past posts or just reading/watching them without commentary, they’re preventing themselves from any downsides of sharing an opinion such as rejection, misunderstanding, or embarrassment. They also have more control on how much of themselves they’re willing to reveal to the general public, and tend to be more open face-to-face or during one-on-one/one-on-few private chats or DMs. This can be seen as a healthy boundary and prevents unnecessary exposure.
Considering many comment sections, especially involving political topics, are meant to stir negative emotional responses to increase engagement, being extra mindful about where, when, and what you comment might not be a bad idea. They might not even take the engagement bait at all. Or if they see a friend of theirs post something vulnerable, they feel more motivated to engage with them personally one-on-one rather than use social media to publicly check in on them.
2. Analytical and reflective mindset
How many times have you gone onto Reddit, YouTube, or any other site and just skimmed past comments that are just different versions of “yes, and,” “no, but,” or “yes, but”? Or the ever insightful, formerly popular comment “First!” in a thread? These silent browsers lean against adding to such noise unless they have some valid and thoughtful contribution (if they bother to comment period).
These non-posters are likely wired on reflective thinking rather than their initial intuition. Not to say that all those who comment aren’t thoughtful, but many tend to react quickly and comment based on their initial feelings rather than absorbing the information, thinking it over, researching or testing their belief, and then posting it. For "lurkers," it could by their very nature to just do all of that and not post it at all, or share their thoughts and findings privately with a friend. All in all, it’s a preference of substance over speed.
3. High sense of self-awareness
Carried over from the first two listed traits, these silent social media users incorporate their concern over their vulnerability and their reflective mindset into digital self-awareness. They know what triggers responses out of them and what causes them to engage in impulsive behavior. It could be that they have engaged with a troll in the past and felt foolish. Or that they just felt sad after a post or got into an unnecessary argument that impacted them offline. By knowing themselves and seeing what’s being discussed, they choose to weigh their words carefully or just not participate at all. It’s a form of self-preservation through restraint.
4. Prefer to observe rather than perform
Some folks treat social media as information, entertainment, or a mix of both, and commenting can feel like they’re yelling at the TV, clapping alone in a movie theater when the credits roll, or yelling “That’s not true!” to a news anchor that will never hear them. But contrary to that, social media is a place where those yells, claps, and accusations can be seen and get a response. By its design, social media is considered by experts and the media as performative, regardless of whether it is positive or negative. Taking all of the previously mentioned traits into account, one can see why they would prefer to “observe the play” rather than get up on the stage of Facebook or X.
On top of that, these non-commenters could be using social media differently than those who choose to fully engage with it. Using this type of navigation, there may be nothing for them to comment about. Some commenters are even vying for this for their mental health. There are articles about how to better curate your social media feeds and manipulate algorithms to create a better social media experience to avoid unnecessary conflict or mentally tiring debate.
If you go on a blocking spree on all of your accounts and just follow the posters that boost you, it could turn your social media into a nice part of your routine as you mainly engage with others face-to-face or privately. In terms of commenting, if your curated Instagram is just following cute dogs and all you have to offer for a comment is “cute dog,” you might just enjoy the picture and then move on with your day rather than join in the noise. These non-commenters aren’t in the show and they’re fine with it.
5. Less motivated by social validation
The last trait that Brown showcases is that social media users who browse without posting tend to be independent from external validation, at least online. Social media is built to grow through feedback loops such as awarding likes, shares, and reposts of your content along with notifications letting you know that a new person follows you or wants to connect. This can lead many people to connect their activity on social media with their sense of self worth, especially with adolescents who are still figuring out their place in the world and have still-developing brains.
Engaging in social media via likes, shares, comments, and posts rewards our brains by having them release dopamine, which makes us feel good and can easily become addictive. For whatever reason, non-commenters don’t rely on social media as a means to gauge their social capital or self worth. This doesn’t make them better than those who do. While some non-commenters could have healthier ways to boost their self worth or release dopamine into their systems, many get that validation from equally unhealthy sources offline. That said, many non-commenters’ silence could be a display of independence and self confidence.
Whether you frequently comment online or don’t, it’s good to understand why you do or don’t. Analyzing your habits can help you determine whether your online engagement is healthy, or needs to be tweaked. With that information, you can then create a healthy social media experience that works for you.