The device could lead to quicker and less invasive sealing of tears and holes in blood vessels, the team believes, holding potential to replace the need for open keyhole surgery on internal blood vessel defects.
Voltaglue was created by NTU associate professor Terry Steele in 2015. Patented by NTU and MIT (Massachusetts Institute of Technology) scientists, Voltaglue is an adhesive that works in wet environments and hardens when a voltage is applied to it.
The new device was jointly developed by Steele with former NTU PhD student Dr Manisha Singh, now at MIT, and associate professor Ellen Roche from MIT’s department of mechanical engineering and institute for medical engineering and Science.
It is made up of two components: an adhesive patch containing Voltaglue, and a modified balloon catheter with retractable wires that can carry electrical current. After inserting the catheter into a blood vessel, the patch can be guided through the body to where the tear is located and be activated using retractable electrodes to glue it shut in a matter of minutes according to the team.
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Dr Singh said that Voltaglue’s stability in wet environments and ability to stick onto soft tissue makes it suitable and effective for repairing blood vessels.
“By combining it with existing, commercially available catheters, we have developed a new delivery mechanism that is minimally invasive, yet flexible and adaptable,” Singh added. “This system shows promise for a diverse range of medical applications, as the suitability of the patch could be tailored according to the needs of the patient.”
Lab experiments on a pig’s heart suggested that the Voltaglue patch can be safely and effectively administered in a variety of situations including withstanding the high pulsatile pressure of blood in arteries like the aorta.
At the site of the break, the catheter balloon expands so that the injury is covered by the Voltaglue patch. A process called electrocuring — adjusting the glue’s hardness by changing the amount of voltage applied to it — allows the patch to adapt to different types of tissue surfaces.
The patch starts to set after 20 seconds and fully hardens between three to five minutes, effectively ‘gluing’ the broken vessel together. The wires, deflated balloon and catheter are then withdrawn.
During the lab experiments, the device was used to close a 3mm defect in an explanted pig aorta connected to a mock heart under continuous blood flow of 10ml per minute.
The team said that the patch was left on for 1,000 physiological stress/strain cycles (heartbeats) — around 15 minutes at 70 bpm. The patch was reportedly found to still be successfully sealing the gap when the aorta was examined after the experiment.
Suited for use in vessels ranging from 7.5 to 30mm in size, researchers said the device could seal defects in organs such as kidneys and oesophagus as well as aorta. Both Voltaglue and the patch are made with entirely degradable bioresorbable material which dissolves in weeks, making the catheter suitable for applications such as vascular grafting, a common surgical procedure used to redirect or seal off blood flow to tumours to kill them off.
It is hoped that one day the device could also deliver patches to repair birth defects such as holes in the heart’s wall. The research has been published in Science Advances.
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