| 1. |
- Pirozzi, I., et al.
(författare)
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Electrohydraulic Vascular Compression Device (e-VaC) with Integrated Sensing and Controls
- 2023
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Ingår i: Advanced Materials Technologies. - : Wiley. - 2365-709X. ; 8:4, s. 2201196-
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Tidskriftsartikel (refereegranskat)abstract
- Right ventricular (RV) failure remains a significant clinical burden particularly during the perioperative period surrounding major cardiac surgeries, such as implantation of left ventricular assist devices (LVADs), bypass procedures or valvular surgeries. Device solutions designed to support the function of the RV do not keep up with the pace of development of left-sided solutions, leaving the RV vulnerable to acute failure in the challenging hemodynamic environments of the perioperative setting. This work describes the design of a biomimetic, soft, conformable sleeve that can be prophylactically implanted on the pulmonary artery to support RV ventricular function during major cardiac surgeries, through afterload reduction and augmentation of flow. Leveraging electrohydraulic principles, a technology is proposed that is non-blood contacting and obviates the necessity for drivelines by virtue of being electrically powered. In addition, the integration of an adjacent is demonstrate, continuous pressure sensing module to support physiologically adaptive control schemes based on a real-time biological signal. In vitro experiments conducted in a pulsatile flow-loop replicating physiological flow and pressure conditions show a reduction of mean pulmonary arterial pressure of 8 mmHg (25% reduction), a reduction in peak systolic arterial pressure of up to 10 mmHg (20% reduction), and a concomitant 19% increase in diastolic pulmonary flow. Computational simulations further predict substantial augmentation of cardiac output as a result of reduced RV ventricular stress and RV dilatation.
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| 2. |
- Kight, Ali, et al.
(författare)
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Decoupling Transmission and Transduction for Improved Durability of Highly Stretchable, Soft Strain Sensing : Applications in Human Health Monitoring
- 2023
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a modular approach to the development of strain sensors for large deformations. The proposed method separates the extension and signal transduction mechanisms using a soft, elastomeric transmission and a high-sensitivity microelectromechanical system (MEMS) transducer. By separating the transmission and transduction, they can be optimized independently for application-specific mechanical and electrical performance. This work investigates the potential of this approach for human health monitoring as an implantable cardiac strain sensor for measuring global longitudinal strain (GLS). The durability of the sensor was evaluated by conducting cyclic loading tests over one million cycles, and the results showed negligible drift. To account for hysteresis and frequency-dependent effects, a lumped-parameter model was developed to represent the viscoelastic behavior of the sensor. Multiple model orders were considered and compared using validation and test data sets that mimic physiologically relevant dynamics. Results support the choice of a second-order model, which reduces error by 73% compared to a linear calibration. In addition, we evaluated the suitability of this sensor for the proposed application by demonstrating its ability to operate on compliant, curved surfaces. The effects of friction and boundary conditions are also empirically assessed and discussed.
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| 3. |
- Pirozzi, Ileana, et al.
(författare)
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Circulatory Support : Artificial Muscles for the Future of Cardiovascular Assist Devices
- 2023
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- Artificial muscles enable the design of soft implantable devices which are poised to transform the way we mechanically support the heart today. Heart failure is a prevalent and deadly disease, which is treated with the implantation of rotary blood pumps as the only alternative to heart transplantation. The clinically used mechanical devices are associated with severe adverse events, which are reflected here in a comprehensive list of critical requirements for soft active devices of the future: low power, no blood contact, pulsatile support, physiological responsiveness, high cycle life, and less-invasive implantation. In this review, we investigate and critically evaluate prior art in artificial muscles for their applicability in the short and long term. We highlight the main challenges regarding the effectiveness, controllability, and implantability of recently proposed actuators and explore future perspectives for attachment, physiological responsiveness, durability, and biodegradability as well as equitable design considerations.
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| 4. |
- Pirozzi, Ileana, et al.
(författare)
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RVEX : Right Ventricular External Device for Biomimetic Support and Monitoring of the Right Heart
- 2022
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Ingår i: Advanced Materials Technologies. - : Wiley. - 2365-709X. ; 7:8, s. 2101472-2101472
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Tidskriftsartikel (refereegranskat)abstract
- Right ventricular (RV) failure remains a significant burden for patients with advanced heart failure, especially after major cardiac surgeries such as implantation of left ventricular assist devices. Device solutions that can assist the complex biological function of heart muscle without the disadvantages of bulky designs and infection-prone drivelines remain an area of pressing clinical need, especially for the right ventricle. In addition, devices that incur contact between blood and artificial surfaces mandate long-term use of blood-thinning medications, carrying increased risks for the patients. This work describes the design of a biomimetic, elastic sleeve to support RV-specific motion via tuned regional mechanical properties. The RV external device (RVEX) in computational models as well as benchtop models and ex vivo (i.e., explanted heart) setups are evaluated to characterize the device and predict functional benefit. Additionally, long-term implantation potential is demonstrated in mice. Finally, the ability to sensorize the RVEX device to yield resistive self-sensing capabilities to continuously monitor ventricular deformation, as demonstrated in benchtop experiments and in live animal surgeries, is proposed.
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