Impossible no more: ACES researchers “get a grip” on cell adhesion

ACES researchers have made possible a technique that allows them to study the interaction between an implantable device and biological tissue, which presents exciting opportunities for those working with biomaterials.

Critical to the performance of an implantable electrode device is the communication of physical, chemical or electrical signals across the electrode/biological tissue interface.

The biological-electrode interface is engineered to attract certain types of cells (and defend against others), or instruct cells to divide and grow, or even become other cell types. The instructions from the material are understood by the cells through chemical recognition, electrical signals, and sensing of physical forces – the cells have molecular-sized components on their outer surface – that remarkably act as transducers to direct information to the inside of the cell.

To date, there have been no methods to measure the signals as they pass across the interface – notwithstanding that it is very difficult to insert a physical measurement probe into a gap that is less than 50 nanometres wide.

Researchers typically need to employ a reductionist approach, effectively “stripping away” parts of the cell, to gain access to the molecular components. Ideally, it would be better to probe the molecular components in their rightful environment – embedded in the membrane of a living cell that is taking instructions from an electromaterial.

PhD student Hongrui Zhang and researchers at the ARC Centre of Excellence for Electromaterials Science have now made it possible to directly probe the cell/electromaterial interface by developing a technique based on Bio-Atomic Force Microscopy, with the work published in the Nature Online Journal, Scientific Reports.

The technique, referred to as Electrochemical-Single Cell Force Spectroscopy, involves attaching a single live cell onto a probe, which is brought into contact with an electrode surface, to measure its molecular forces of adhesion. Electrochemical capabilities enable the real-time detection of single molecule interactions under electrical control and, in doing so, the research provides the first molecular level insights into this fascinating phenomenon for living cells in a biologically relevant environment.

A/Prof. Michael Higgins, who is a co-author, believes the work will have a significant impact on those concerned with the design of electronic surfaces in biology and amplifying effects arising from electrical stimulation.

“We have no doubt this approach will be embraced not just by those involved in the development of the electromaterials used in this study but any surface wherein electrical stimulation is used,” he said.

Significantly, the research is expected to provide a fundamental understanding of single receptor binding and formation of their complexes at material surfaces with ultra-high sensitivity and resolution. The work is already gaining significant attention in the immense field of biomaterials.

The work is supported through the Chinese Scholarship Council, ARC Australian Research Fellowship of A/Prof. Michael Higgins, ARC Laureate Fellow of Prof. Gordon Wallace, and ARC Centre of Excellence for Electromaterials Science.

Published Article: H. Zhang, P. J.  Molino, G. G. Wallace, M. J. Higgins (2015). Quantifying Molecular-Level Cell Adhesion on Electroactive Conducting Polymers using Electrochemical-Single Cell Force Spectroscopy. Scientific Reports.