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Light emitting dots to image lysosomes

Researchers have synthesised light-emitting graphene quantum dots that can be used to selectively track and image lysosomes, an enzyme-rich cellular organelle that breaks down a cell’s waste products1.

The dots are potentially useful for monitoring and diagnosing diseases that have been linked to the dysfunction of lysosomes.

Existing imaging techniques can image lysosomes. Most of these techniques, however, fail to clearly distinguish lysosomes from other cellular organelles such as mitochondria.

In search of a better imaging technique, scientists from the CSIR-Central Salt and Marine Chemicals Research Institute in Bhavnagar, Gujarat, prepared the quantum dots from neem root extract using a simple water-based heating method. They then tested the efficiency of the quantum dots in tracking and imaging lysosomes in cultured mice cells and zebrafish.

They incubated specific mice cells with the dots and then exposed them to infrared light. On being exposed to such radiation, the cells emitted a bright green light, indicating the presence of the dots inside the cells. The dots selectively entered the cells’ lysosomes.

The researchers then soaked zebrafish embryos and larvae in a solution containing the quantum dots. Three days later, the dots were found inside the lysosomes of the zebrafish larvae’s digestive system.

The team, led by Sumit Kumar Pramanik and Amitava Das, says that the dots also have the potential to image lysosomes in liver cells. In the next phase of research, they plan to synthesise quantum dots that can enter a cell’s nucleus – an innovation that could pave the way to cancer diagnosis.



  1. Singh, H. et al. Two photon excitable graphene quantum dots for structured illumination microscopy and imaging applications: lysosome specificity and tissue-dependent imaging. Chem. Commun. (2018) doi: 10.1039/C8CC08610A

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