Scientists can spot inflammatory cells in fat using quantum dots, which shine brightly

Doctors and researchers need to see into bodies to diagnose and cure diseases accurately. Medical imaging tools have come a long way from the simple X-ray, but most of the current tools are still too coarse to estimate the number of cells or specific types of cells deep within the body's tissues.

According to new studies conducted in mice by the University of Illinois, quantum dots can accomplish this.

"Quantum dots can detect and measure things in the body that are extremely active and difficult to observe. They allow us to count cells, pinpoint their exact locations, and track changes over time. I believe it is a significant step forward. "According to Andrew Smith, a professor in the University of Iowa's Department of Bioengineering and a co-author on the ACS Nano paper,

Quantum dots are small, lab-grown nanoparticles with unique optical properties that may be detected using standard microscopy, tomography (e.g., PET/CT scanners), and fluorescence imaging. Bioengineers like Smith can make them glow in specific colors and produce light in the infrared range depending on their size and composition.

"It's unusual to emit infrared light. Tissues emit extremely little light in the infrared; therefore, they look brilliant when placed in the body. We can see deeper into the body and quantify things more precisely than we could with visible-range technologies, "Smith explains.

Smith and colleagues used quantum dots on macrophages in their ACS Nano work.

Macrophages are activated when our systems need to eat infections or clear up cellular trash. One of its responsibilities is to cause inflammation, making the environment hostile to dangerous microorganisms. However, they might occasionally be too good at what they do. Chronic inflammation caused by macrophage activity can lead to diabetes, cardiovascular problems, malignancies, and more, depending on their tissue.

The macrophages in fat, or adipose tissue, were particularly interesting to the University of Illinois scientists.

"The number of macrophages in adipose tissue increases with weight gain and obesity. They tend to shift toward an inflammatory phenotype, which leads to the development of insulin resistance and metabolic syndrome. The number and location of macrophages in adipose tissue, particularly in vivo, are little understood. "Kelly Swanson, a co-author of the study and the Kraft Heinz Company Endowed Professor in Human Nutrition in the Department of Animal Sciences at the University of Illinois, agrees.

"The quantum dots developed by our lab enable improved measurement and characterization of the cells in adipose tissue and their geographic distribution," he says.

Quantum dots coated with dextran, a sugar molecule that similarly targets macrophages in fat tissue, were developed by the researchers. They injected these quantum dots into obese mice as a proof-of-concept and compared imaging findings to dextran alone, the current standard for imaging macrophages.

Quantum dots beat dextran alone across all imaging platforms, including simple optical approaches.

"Quantum dots emit a tremendous quantity of light, allowing us to quantify individual cell types and pinpoint their location more precisely," Smith explains. "Because of the high light output, optical techniques can be used far more accessible than other imaging technologies. They are inexpensive tools that may be used in a small clinic compared to MRI and PET scanners. Anyone could own one."

Although quantum dots have yet to be employed in people, Swanson envisions a future in which a simple optical technique such as ultrasonography may be used to non-invasively diagnose and track inflammatory macrophages in obese individuals.

"Even if a patient's weight hasn't changed, a doctor could use a gadget like an ultrasound to scan them and see if their cell types are changing. More inflammatory cells could help predict insulin resistance and other problems. According to new research, "he declares, "I'm interested in it because of its diagnostic properties."

Quantum dots aren't utilized in people since they're often created with heavy metals like cadmium and mercury, and scientists aren't sure how they're digested and eliminated. Smith and his colleagues are developing quantum dots built with safer elements, but they are still a vital research tool in the meanwhile. For example, their long circulation period—nine times longer than dextran in the current study—could provide diagnosticians with a technique to move beyond a snapshot in time.

"Even within a single day, macrophages have many variations." "In the middle of the day, adipose tissue may have a very high value, and then it declines dramatically," Smith explains. "We can sacrifice animals at the start and end of a day to investigate animal research trends, but with quantum dots, we might not have to." You may follow the progress of a single animal over time.

"Quantum dots have a lot of potential in animal research." So even if quantum dots never reach people, if we never figure out how to make them non-toxic, the value is still enormous.