Magnetic Microbots Enhance Quantum Sensing in Cells

Cells, as fundamental units of life, present unique challenges for scientific measurements due to their soft and viscous nature. Recent advancements reported by researchers from the Indian Institute of Science (IISc) highlight a novel technique employing magnetic microbots to navigate quantum sensors within living cells. This innovation paves the way for real-time, minimally invasive measurements of biological parameters such as viscosity and temperature.

Understanding the Quantum Sensor

The research led by Ambarish Ghosh, a professor at the Center for Nanoscience and Engineering (CeNSE) at IISc, integrates a nanodiamond containing a nitrogen vacancy (NV) defect with a precisely controlled microbot. An NV defect refers to a specific fault within the diamond lattice, wherein a carbon atom is substituted by a nitrogen atom near an empty space. This defect possesses electrons whose quantum spin states are sensitive to the surrounding environment, making them valuable for detecting changes in physical properties such as temperature and magnetic fields.

The fluorescence emitted when a laser excites the nanodiamond serves as a tool for measuring various internal cellular parameters. Nevertheless, positioning such sensors within cells had been challenging using traditional methods like optical tweezers, which could potentially damage cellular structures due to intense light exposure.

Innovation in Navigation: Magnetic Microbots

The key solution proposed by the IISc team involves attaching the nanodiamond sensor to a magnetically driven microbot that operates similarly to a corkscrew. The microbot, made with iron, aligns with an externally applied rotating magnetic field, translating its rotation into forward motion. This capability enables precise control of the quantum sensor in three-dimensional space without the drawbacks associated with light-based manipulation.

The advantages of this method extend to reducing potential phototoxicity and heating of cells, as light is used exclusively for measurement purposes rather than for moving the sensor. Below is a comparative analysis of both techniques:

Addressing Challenges: Noise and Magnetic Interference

A further complication encountered at the nanoscale is the uncontrollable Brownian motion, which can lead to random orientations of the sensor, increasing measurement noise. The use of magnetic manipulation mitigates this issue, allowing researchers to achieve stable positioning of the nanodiamond while collecting reliable data.

“We are able to counter Brownian motion with magnetic manipulation. This makes this platform more promising than optics or any other techniques,” stated Ghosh.

Designing the Quantum Sensor

The successful integration of the nanodiamond with the magnetic motor required careful consideration to prevent mutual interference between the components. As Eklavy Vashist, the research associate and first author on the study notes, “It was not intuitive because the sensor itself may be affected by the magnetic elements.” This issue was resolved by positioning the nanodiamond approximately one micron away from the microbot's iron head, where the magnetic influence on the sensor is negligible.

Applications of the Sensor

The innovative sensor is capable of performing detailed analyses inside living cells, which include measuring Reactive Oxygen Species (ROS). Understanding ROS is vital to research areas including cancer pathology and aging processes.

Conclusion

The development of magnetic microbots that can steer quantum sensors in living cells marks a significant advancement in biomedical research. This technology promises to enhance our ability to perform minimally invasive measurements, paving the way for enhanced understanding of cellular environments.

Publication Details

Eklavy Vashist et al., “Magnetically Maneuvered Quantum Sensors,” Advanced Functional Materials (2026).

Retrieved March 24, 2026