Engineering researchers develop breakthrough know-how to measure rotational movement of cells — ScienceDaily


Mechanics performs a basic function in cell biology. Cells navigate these mechanical forces to discover their environments and sense the behaviour of surrounding residing cells. The bodily traits of a cell’s surroundings in flip impression cell capabilities. Subsequently, understanding how cells work together with their surroundings offers essential insights into cell biology and has wider implications in drugs, together with illness prognosis and most cancers remedy.

To this point, researchers have developed quite a few instruments to review the interaction between cells and their 3D microenvironment. Some of the in style applied sciences is traction power microscopy (TFM). It’s a main methodology to find out the tractions on the substrate floor of a cell, offering necessary info on how cells sense, adapt and reply to the forces. Nevertheless, TFM’s utility is proscribed to offering info on the translational movement of markers on cell substrates. Details about different levels of freedom, resembling rotational movement, stays speculative resulting from technical constraints and restricted analysis on the subject.

Engineering consultants on the College of Hong Kong have proposed a novel method to measure the cell traction power subject and deal with the analysis hole. The interdisciplinary analysis crew was led by Dr Zhiqin Chu of the Division of Electrical and Digital Engineering and Dr Yuan Lin of the Division of Mechanical Engineering. They used single nitrogen-vacancy (NV) centres in nanodiamonds (NDs) to suggest a linear polarization modulation (LPM) methodology which may measure each, the rotational and translational motion of markers on cell substrates.

The research offers a brand new perspective on the measurement of multi-dimensional cell traction power subject and the outcomes have been revealed within the journal Nano Letters. The analysis, entitled ‘All-Optical Modulation of Single Defects in Nanodiamonds: Revealing Rotational and Translational Motions in Cell Traction Drive Fields’, can also be featured because the supplementary cowl of the journal.

The analysis confirmed high-precision measurements of rotational and translational movement of the markers on the cell substrate floor. These experimental outcomes corroborate the theoretical calculations and former outcomes.

Given their ultrahigh photostability, good biocompatibility, and handy floor chemical modification, fluorescent NDs with NV centres are glorious fluorescent markers for a lot of organic functions. The researchers discovered that primarily based on the measurement outcomes of the connection between the fluorescence depth and the orientation of a single NV centre to laser polarization course, high-precision orientation measurements and background-free imaging may very well be achieved.

Thus, the LPM methodology invented by the crew helps clear up technical bottlenecks in mobile power measurement in mechanobiology, which encompasses interdisciplinary collaborations from biology, engineering, chemistry and physics.

“Nearly all of cells in multicellular organisms expertise forces which might be extremely orchestrated in house and time. The event of a multi-dimensional cell traction power subject microscopy has been one of many biggest challenges within the subject,” stated Dr Chu.

“In comparison with the standard TFM, this new know-how offers us with a brand new and handy device to research the actual 3D cell-extracellular matrix interplay. It helps obtain each rotation-translational motion measurements within the mobile traction subject and divulges details about the cell traction power,” he added.

The research’s most important spotlight is the flexibility to point each the translational and rotational movement of markers with excessive precision. It’s a huge step in the direction of analysing mechanical interactions on the cell-matrix interface. It additionally gives new avenues of analysis.

By way of specialised chemical compounds on the cell floor, cells work together and join as a part of a course of known as cell adhesion. The best way a cell generates pressure throughout adhesion has been primarily described as ‘in-plane.’ Processes resembling traction stress, actin circulate, and adhesion progress are all linked and present advanced directional dynamics. The LPM methodology might assist make sense of the difficult torques surrounding focal adhesion and separate totally different mechanical hundreds at a nanoscale stage (e.g., regular tractions, shear forces). It might additionally assist perceive how cell adhesion responds to several types of stress and the way these mediate mechanotransduction (the mechanism by which cells convert mechanical stimulus into electrochemical exercise).

This know-how can also be promising for the research of varied different biomechanical processes, together with immune cell activation, tissue formation, and the replication and invasion of most cancers cells. For instance, T-cell receptors, which play a central function in immune responses to most cancers, can generate extraordinarily dynamic forces important to tissue progress. This high-precision LPM know-how could assist analyse these multidimensional power dynamics and provides insights into tissue growth.

The analysis crew is actively researching methodologies to broaden optical imaging capabilities and concurrently map a number of nanodiamonds.

This paper entitled ‘All-Optical Modulation of Single Defects in Nanodiamonds: Revealing Rotational and Translational Motions in Cell Traction Drive Fields’ is revealed within the journal Nano Letters and featured because the supplementary cowl. Hyperlink:

Media Enquiries Ms Celia Lee, College of Engineering, HKU (Tel: 3917 8519; E mail: or Ms Charis Lai, College of Engineering, HKU (Tel: 3917 1924; E mail: