Medical sutures could provide a conduit to deliver anti-inflammatory treatments directly into damaged tissue. Recent research has demonstrated that drugs can be drawn along the threads of the stitches themselves before being widely dispersed into soft tissue models.

This enticing approach to targeted wound treatment has recently been trialled by researchers from the ARC Centre of Excellence for Electromaterials Science (ACES) utilising electricity, standard sutures, anti-inflammatory medicines and a hydrogel testbed.

The team, led by Professor Brett Paull and including scientists from ACES’ University of Tasmania (UTAS) and University of Wollongong (UOW) sites, has shown that their electrofluidic method allowed the drug to spread across the full 3D space of the testbed, and after two hours of electrical stimulation, over 80 per cent of the drug was retained within the target area.

To provide effective delivery of treatment in this way, medicine needs to travel quickly along the suture, but then slow down once it arrives in the target tissue to allow uptake of the drug into the body.

Professor Paull and his colleagues have shown that their electrofluidic approach enables them to vary the speed that bioactive molecules are carried along a typical absorbable suture by employing an electric field to manipulate the medicine.

Most water-soluble species carry some sort of charge and will therefore migrate towards either positive or negative electrodes when exposed to an electric current.

The principle of driving medicine along a fibre using a current in this way has been demonstrated previously, but it’s never been tested in a biological model. To see if the approach could work in the wild, the ACES researchers turned to ANFF Materials experts to create a testbed tissue using a hydrogel called GelMA.

GelMA is a fantastic replica of natural tissue ¬ñ it’s made of denatured collagen, a protein vital to building connective tissue within the body, and can be cured to varying degrees by exposing it to different amounts of UV light to produce different mechanical properties.

Using this highly accurate model allowed the researchers to investigate aspects of how the delivery approach could work with live cell cultures.

The researchers use the electrophoresis phenomenon to drive bioactive molecules rapidly along the thread towards the desired distribution area by placing electrodes at either end of the suture and passing a small current through it. Once within the target tissue, the current is dropped, causing the flow to slow and allowing uptake of the drug into the biological model. Once the required time has passed, the current is ramped up again to sweep out the remaining bioactive and potentially any resultant cell metabolites of interest.

“The fascinating aspect of this work lies within its simplicity,” Professor Paull said. “We can actually be highly quantitative in delivery of these bioactive species using some very simple materials, and not only deliver from A to B, but anywhere in-between.”

“Our work, supported by ANFF Materials, showed that more than 80 per cent of the anti-inflammatory stayed within the hydrogel, and therefore indicates distinct promise for use in real tissue.

We look forward to taking this research further.”