Magnetic-Plasmonic Hybrid Nanoparticles Isolate Lysosomes from Cells

Researchers at the Japan Advanced Institute of Science and Technology have developed a method to isolate intact lysosomes from cells. The technique is rapid and produces samples of high purity. Lysosomes are the garbage-disposal organelles within a cell, and they are involved in numerous diseases, from lysosomal storage diseases to autoimmune disorders, certain cancers, and neurodegenerative diseases. However, they are difficult to study, as current techniques to isolate lysosomes from cells result in samples with poor purity and damaged or altered lysosomes. This new approach uses nanotechnology to rapidly extract a high-purity lysosome sample from cells.

Lysosomes digest large molecules within cells and produce metabolites. When this process goes awry, serious disease can result, something that researchers are trying to study in detail. However, isolating these tiny organelles is a challenge. One approach involves centrifuging samples from lysed cells very fast, which separates the lysosomes out based on their density. However, this a fairly crude way to isolate lysosomes, and many other organelles often get mixed into the isolate. It is also pretty slow.

Another technique involves using magnetic beads covered in antibodies that bind lysosomes, allowing researchers to isolate them with a magnet. This results in a purer isolate, but alters the proteins in the lysosomes, affecting any protein analysis that scientists may wish to conduct. To address these issues, the researchers in Japan have developed a new method to isolate lysosomes.

They have created magnetic-plasmonic hybrid nanoparticles that contain an iron-cobalt alloy and silver. The particles are also coated with amino dextran, and unlike other magnetic particles used for lysosome isolation, cells are happy to endocytose them, meaning they are ingested and ultimately end up in an intact lysosome. The technique then involves rupturing the cells and harvesting the intact lysosomes using a magnet.

The particles can also be visualized using plasmon imaging, letting researchers track their progress through a cell until they are bound within a lysosome. This imaging meant that the researchers were able to calculate the best time to lyse the cells and harvest the lysosomes, as they knew precisely when they were within the lysosomes. The method is very fast and results in highly pure lysosome samples.

“We found that the maximum time required to isolate lysosomes after cell rupture was 30 minutes, which is substantially shorter than the time required using centrifugation-based techniques, which typical require a minimum separation time of several hours,” said Shinya Maenosono, a researcher involved in the study. “Given the profound relation of lysosomes with many cellular metabolites, a deeper understanding of lysosomal function is necessary to determine its regulation in different cell states. Therefore, our technique can contribute to better understanding and treatment of lysosomal diseases in the future.”

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