Nanostructured flow-diverter and sensor a promising approach for aneurysm management
The soft, stretchable, flexible sensor system is designed to overcome the challenges of cerebral blood vessel navigation. The device is highly stretchable (500 percent radial stretching) and bendable (180 degrees), and capable of measuring intra-aneurysmal haemodynamics. [ACS Nano 2018, doi: 10.1021/acsnano.8b04689]
“The nanostructured sensor system could provide advantages for patients, including a less invasive treatment for aneurysm and an active monitoring capability. The system could provide monitoring after surgery, allowing doctors to follow up with quantitative measurements of how well the flow diverter is working,” said investigator Dr Woon-Hong Yeo.
The flow-diverter system was tested on a porcine artery with an artificial aneurysmal sac. The device was placed at the centre of the neck of the aneurysm with flexible microwires exiting the vessel for data acquisition.
The capacitance fluctuation cause by a deformed dielectric layer is the main mechanism behind the sensor response. Varying degrees of physical deflection of the sensor led to a respective capacitance change.
Various materials were found to be advantageous for sensor construction. These included nitinol, which is hyperelastic, gold, which has been widely accepted for use in biomedical devices, and magnesium, which can be naturally absorbed in the body for transient sensing.
In vitro testing using ovine blood also demonstrated low platelet deposition (ie, haemocompatibility) with the sensors as compared with other graft materials, such as expanded polytetrafluoroethylene (ePTFE) graft and polyethylene terephthalate fabric (Dacron).
The investigators are currently working on the development of a wireless telemetry unit to incorporate with the flow-diverter device for real-time and continuous monitoring of haemodynamics.Post-treatment monitoring for aneurysms is important because of possible complications occurring within 1 month. Flow-diverting devices require both short-term and long-term follow-up after treatment. The most common follow-up method is angiography, which is both costly and invasive. [Neuroradiol J 2015:28;365-375]