IIT Mandi Designs Super Resolution For Nanoprobe Imaging

Mandi: Indian Institute of Technology Mandi researchers have designed gold nanoclusters as an efficient fluorescent nanoprobe for lysosome imaging. Out of multiple organelles present in an animal cell, lysosomes play a significant role in cellular processes. A lysosome is a membrane-bound cell organelle that contains digestive enzymes. Lysosomes act as a waste disposal system for the cell by digesting obsolete materials in the cytoplasm, break-down invading viruses or bacteria, digests large structures or cellular debris, and clears them.

The research team is led by Dr. Chayan Nandi, Associate Professor, School of Basic Sciences, IITMandi. The team includes Dr. Amit Jaiswal, Assistant Professor, School of Basic Sciences, IITMandi, and research scholars Mr. Aditya Yadav, Mr. Navneet C. Verma, Ms. Chethana Rao and Mr. Pushpendra M. Mishra. The results of their work have been published in the Journal of Physical Chemistry Letters.

Understanding the functional modalities of lysosomes in live conditions is a very complex phenomenon due to their very small size down to 50-500 nanometres (nm), even with the availability of high-end imaging techniques. The research team took up the challenge to image the real size of lysosomes using super-resolution microscopic imaging technique. The major challenge in super-resolution microscopic imaging is to get an efficient fluorescent probe, which at the same time with its intrinsic optical properties, can image the organelle to its real subnanometer size and also does not damage the cellular structure by posing any toxic effect.

Nanoprobe imaging

In this work, the researchers have designed a bovine serum albumin protein conjugated red emissive gold nanoclusters as an efficient fluorescent nanoprobe for lysosome imaging. With this approach, the diameter of the lysosome is obtained as 59 nm, which is very close to the original diameter of the smallest lysosome in HeLa cells. HeLa is the oldest and most commonly used immortal cervical cancer cell line. They have been instrumental in studying human diseases, especially cancer.

The gold nanoclusters, because of its exciting photoluminescence properties, easy renal clearance from the body, and nontoxic nature, have tremendous biomedical applications. “Unfortunately, gold nanoclusters have never been explored for super-resolution microscopic imaging, we are the first to report its applicability as a fluorescent probe for single-molecule localization-based microscopic technique”, says Dr. Chayan Nandi. “Because of its extremely small size, intrinsic fluorescence properties suitable for super-resolution microscopic imaging and the non-toxic nature, the gold nanocluster could be universally used for high-end optical imaging”, he added.

The next step of this research is to make these gold nanoclusters as a universal probe for other multimodal and correlative bioimaging techniques.

“Owing to its high electronic contrast the developed nanoclusters, along with the use in super resolution optical microscopy, could also be used as a probe for transmission and scanning electron microscope in a correlative manner and thus will unveil a huge number of unresolved biological problems in live cell condition,” says Dr. Chayan Nandi.

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