Quantum dots (QDs) have recently found their applications in different areas such as industrial inspection, surveillance, and spectroscopy. These man-made crystals are actually semiconductor nanoparticles which exhibit both optical and electronic properties. In a new study, scientists proved the possibility of synthesizing quantum dots in the nucleus of live cells.
Cellular Transport Mechanism
In eukaryotic organisms, the nucleus is considered as the largest and most important organelle. This cellular component serves as the main site for the storage, replication, and transcription of genetic materials. Because of this capability, the nucleus plays an important role in cell growth, metabolism, proliferation, differentiation, and other biological functions.
The transport of materials in and out of the nucleus relies on an enclosure called nuclear membrane. This layer separates the material within the nucleoplasm from the cytoplasm, which controls the exchange of information and materials inside and outside the nucleus.
As a result, the synthesis of substances within the nucleus is typically rhythmic and regular. It is also under tight regulation according to an organism's physiological needs.
There have been many studies which reported the synthesis and related mechanisms of important biological substances in the nucleus. However, experts have not yet reported the in-situ synthesis of nanoparticles in the nucleus of live cells, let alone the associated regulatory mechanisms of such synthesis.
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In-Situ Synthesis in Cell Nucleus
In a recent study, researchers from Nankai University attempted to conduct an in-situ synthesis of quantum dots in the nucleus of living cells. Their findings are discussed in the paper "In-situ synthesis of quantum dots in the nucleus of live cells".
Led by Dr. Hu Yusi, the research team attempted to explore the molecular mechanism of quantum dot synthesis in the nucleus of live cells. During the investigation of quantum dot synthesis in mammalian cells, the scientists discovered that the treatment containing glutathione (GSH) improved the reducing capacity of the cell.
The generated quantum dots were not distributed uniformly within the cell but concentrated in a specific area. Through a series of experiments, the team confirmed that this area is indeed the nucleus of the cell. It was found that the nucleus contains Bcl-2, a GSH transport protein which delivers GSH into the nucleus in large quantities. This enhances the reducing ability within the nucleus.
Meanwhile, GSH was also found to expose thiol groups on proteins, leading to conditions that would generate Cd precursors. Combining these factors allowed the abundant synthesis of quantum dots in the cell nucleus.
According to Professor Pang Dai-Wen, their research achieves the precise synthesis of quantum dots in live cells at the subcellular level. This can be very beneficial in synthetic biology which mainly focuses on live cell synthesis of organic molecules through reverse genetics.
Scientists rarely observe the live cell synthesis of inorganic functional materials. This study does not involve complex genetic modifications, but instead achieves the target synthesis of inorganic fluorescent nanomaterials in cellular organelles. This was done by regulating the content and distribution of GSH within the cell. This approach addresses the flaws in synthetic biology concerning the synthesis of inorganic materials.
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