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The Shadow of Heavy Metals: Why Are Researchers Rushing to Find Cadmium-Free Quantum Dots?
Quantum Dots (QDs) are semiconductor nanoparticles smaller than 10 nanometers and are valued for their unique optical absorption and photoluminescence properties. The fluorescence emission peaks of these nanoparticles are size-dependent on their diameters. Common quantum dot materials include cadmium series (such as CdTe, CdSe, CdS), indium series (such as InP, InAs) and lead series (such as PbSe, PbS). wait. However, most commercial quantum dots are still based on cadmium-containing products, and the toxicity of cadmium ions to living organisms has attracted widespread attention. With the increasing awareness of environment and health, many researchers began to focus on the development of Cadmium-Free Quantum Dots (CFQDs) in the 2010s.
Applications and prospects of cadmium-free quantum dots
With the development of cadmium-free quantum dots, many new materials such as doped zinc-sulfur/zinc-selenium quantum dots, graphene quantum dots and silicon quantum dots have demonstrated low toxicity and high stability, becoming ideal alternatives for biological applications. Taste. These cadmium-free quantum dots can be used for imaging of target cells and tissues and for precise drug delivery monitoring with DNA/peptide functionalized quantum dots. Using different imaging techniques, such as confocal microscopy and multi-photon microscopy, through these stable fluorescent labels, researchers can observe cells and tissue structures with higher resolution and better biocompatibility.
The flexibility of cadmium-free quantum dots is also reflected in the possibility of combining with other reagents such as metal nanoparticles, radioactive labels and Raman tags to achieve multi-modal imaging.
In addition, the designed cadmium-free quantum dots also have the potential to serve as nanoplatforms for non-invasive treatments and diagnostics (i.e., theranostics). In recent years, the potential of cadmium-free quantum dots in next-generation solar cells and display applications has also attracted the attention of the scientific research community. The discovery and application of these new materials could revolutionize our understanding of quantum dots.
Cadmium-free quantum dots revolutionize medicine
As the field of biomedicine develops, scientists are constantly looking for new ways to treat cancer. Traditional chemotherapy uses a full range of toxic chemicals, but the treatment of disease symptoms is often accompanied by more off-target injuries. Therefore, finding more effective and non-toxic alternatives has become an urgent task. In this regard, cadmium-free quantum dots show great potential.
Michael Sailor and his team at the University of California, San Francisco, have developed the first cadmium-free quantum dots that can shine bright enough for doctors to examine internal organs, and the drugs can quickly degrade into harmless by-products after release.
The core of this research lies in the silicon wafer material used. When these quantum dots are degraded in the body, the silicic acid produced is harmless to the body and helps the growth of bones and tissues. This is undoubtedly a cancer treatment opens up a new direction.
Technical cases and applications
Practical applications of cadmium-free quantum dots also include the development of a variety of materials. For example, zinc-sulfur quantum dots have been used to detect food toxins, specifically aflatoxin–B1, a toxin that causes liver failure. These well-designed zinc-sulfur quantum dots can not only effectively detect environmental pollutants, but can also be used to decompose industrial pollutants, such as naphthalene and other harmful molecules, in photocatalytic reactions.
Another type of cadmium-free quantum dot based on indium, such as CuInS2, has been proven to be a safe fluorescent label and can emit light in the near-infrared region.
This type of quantum dots also performs well in releasing anti-cancer drugs. Studies have shown that while releasing anti-cancer drugs, these quantum dots can also provide real-time imaging of cancer cells and affect cells with low toxicity.
In addition, silicon quantum dots are also a highly valued option. They can be used in photochemical and biological applications and have even improved the energy conversion efficiency of solar cells in some experiments. Silicon quantum dots can emit light stably under a variety of chemical conditions, showing their versatility in biochemical detection.
Ending Thoughts
In summary, with the rising demands for environmental protection and health, the development of cadmium-free quantum dots is not only a step forward in science and technology, but also an exploration of future medicine. How will these new materials affect our lives and the direction of treatment? Is it worthy of our consideration and expectation?
