India’s First Covalent Magnetic Tweezer At Ashoka University

Ashoka University houses the first Covalent Magnetic Tweezer (CMT) in India, developed by Dr. Shubhasis Haldar, who works in the field of Mechanical Biochemistry. With the help of Prof. Julio Fernandez, Columbia University, the CMT is devised to monitor the effect of force on protein molecules and can also be used for drug testing and drug designing.

File photo of Ashoka University

The Covalent Magnetic Tweezer is so cutting edge because it uses magnetic force to examine molecules. The total cost of the CMT is less than 4 lakhs rupee, whereas a similar instrument abroad will cost millions.

Running or stretching sets force on several muscle proteins in the body. The CMT uses magnetic force to replicate the same occurrence and detect this force on proteins. With the CMT, the unfolding kinetics, refolding kinetics and equilibrium can be assessed on the same plot with a single protein. A similar force spectroscopy instrument would cost millions, while the CMT is estimated at less than 4 lakh rupees. 


The CMT has several advantages over other force spectroscopy devices. The AFM can monitor the protein in the high force range, and the Optical Tweezer can monitor the protein in the low force range. The CMT can monitor proteins both in the high and low force range. The CMT also allows the user to monitor a single protein molecule for 2-3 weeks, whereas the AFM or TEM can hold a protein for a maximum of 100 secs.   

Another exclusive feature of the CMT is the ability to add drugs during the experiment. Once the protein is chosen and its properties checked, a drug target is added. After its effects are analyzed, the first drug can be washed out, and the second drug can be added and so on. By testing several drugs in a short span, the CMT has great potential in the field of drug designing.

It was the 1987 invention of the Optical Tweezer, which allows living cells to be held with laser beam fingers that won Arthur Ashkin the Physics Nobel Prize, in 2018. 


To understand the working of the CMT, an octamer of the same protein is used. One end of the octamer is stitched to the glass using HaloTag Chemistry, while the other end is stitched to a paramagnetic bead using biotin-streptavidin chemistry. The CMT allows the user to increase the force on the protein by changing the position of the magnet. The magnet can move at a constant velocity or can be adjusted instantaneously to best suit the experiment. Pushing the magnet downwards, increases the force on the protein, causing the protein to unfold. If the force is decreased, the protein refolds. When proteins hop between unfolded and refolded states, data about equilibrium is released.  

Sciences at Ashoka University:

The science programme at Ashoka University creates a strong appetite for research in young students. Students are guided by well-renowned faculty and scientists even at the undergraduate level and acquire current and in-depth knowledge of the science subjects. Ashoka University provides students with sophisticated labs and high-end research equipment, which empowers them through hands-on experience. Ashoka University offers Mathematics, Computational Science, Physics and Biology. 

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