All Publications

  • Circulatory Support: Artificial Muscles for the Future of Cardiovascular Assist Devices. Advanced materials (Deerfield Beach, Fla.) Pirozzi, I., Kight, A., Han, A. K., Cutkosky, M. R., Dual, S. A. 2023: e2210713


    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. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/adma.202210713

    View details for PubMedID 36827651

  • Decoupling Transmission and Transduction for Improved Durability of Highly Stretchable, Soft Strain Sensing: Applications in Human Health Monitoring. Sensors (Basel, Switzerland) Kight, A., Pirozzi, I., Liang, X., McElhinney, D. B., Han, A. K., Dual, S. A., Cutkosky, M. 2023; 23 (4)


    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.

    View details for DOI 10.3390/s23041955

    View details for PubMedID 36850551

    View details for PubMedCentralID PMC9967534

  • Electrohydraulic Vascular Compression Device (e-VaC) with Integrated Sensing and Controls ADVANCED MATERIALS TECHNOLOGIES Pirozzi, I., Kight, A., Liang, X., Han, A., Ennis, D. B., Hiesinger, W., Dual, S. A., Cutkosky, M. R. 2022
  • DynaRing: A Patient-Specific Mitral Annuloplasty Ring With Selective Stiffness Segments. Journal of medical devices Frishman, S., Kight, A., Pirozzi, I., Maddineni, S., Imbrie-Moore, A. M., Karachiwalla, Z., Paulsen, M. J., Kaiser, A. D., Woo, Y. J., Cutkosky, M. R. 2022; 16 (3): 031009


    Annuloplasty ring choice and design are critical to the long-term efficacy of mitral valve (MV) repair. DynaRing is a selectively compliant annuloplasty ring composed of varying stiffness elastomer segments, a shape-set nitinol core, and a cross diameter filament. The ring provides sufficient stiffness to stabilize a diseased annulus while allowing physiological annular dynamics. Moreover, adjusting elastomer properties provides a mechanism for effectively tuning key MV metrics to specific patients. We evaluate the ring embedded in porcine valves with an ex-vivo left heart simulator and perform a 150 million cycle fatigue test via a custom oscillatory system. We present a patient-specific design approach for determining ring parameters using a finite element model optimization and patient MRI data. Ex-vivo experiment results demonstrate that motion of DynaRing closely matches literature values for healthy annuli. Findings from the patient-specific optimization establish DynaRing's ability to adjust the anterior-posterior and intercommissural diameters and saddle height by up to 8.8%, 5.6%, 19.8%, respectively, and match a wide range of patient data.

    View details for DOI 10.1115/1.4054445

    View details for PubMedID 35646225

  • RVEX: Right Ventricular External Device for Biomimetic Support and Monitoring of the Right Heart ADVANCED MATERIALS TECHNOLOGIES Pirozzi, I., Kight, A., Shad, R. A., Han, A., Dual, S. A., Fong, R., Jia, A., Hiesinger, W., Yock, P., Cutkosky, M. 2022
  • A new open-access platform for measuring and sharing mTBI data. Scientific reports Domel, A. G., Raymond, S. J., Giordano, C., Liu, Y., Yousefsani, S. A., Fanton, M., Cecchi, N. J., Vovk, O., Pirozzi, I., Kight, A., Avery, B., Boumis, A., Fetters, T., Jandu, S., Mehring, W. M., Monga, S., Mouchawar, N., Rangel, I., Rice, E., Roy, P., Sami, S., Singh, H., Wu, L., Kuo, C., Zeineh, M., Grant, G., Camarillo, D. B. 2021; 11 (1): 7501


    Despite numerous research efforts, the precise mechanisms of concussion have yet to be fully uncovered. Clinical studies on high-risk populations, such as contact sports athletes, have become more common and give insight on the link between impact severity and brain injury risk through the use of wearable sensors and neurological testing. However, as the number of institutions operating these studies grows, there is a growing need for a platform to share these data to facilitate our understanding of concussion mechanisms and aid in the development of suitable diagnostic tools. To that end, this paper puts forth two contributions: (1) a centralized, open-access platform for storing and sharing head impact data, in collaboration with the Federal Interagency Traumatic Brain Injury Research informatics system (FITBIR), and (2) a deep learning impact detection algorithm (MiGNet) to differentiate between true head impacts and false positives for the previously biomechanically validated instrumented mouthguard sensor (MiG2.0), all of which easily interfaces with FITBIR. We report 96% accuracy using MiGNet, based on a neural network model, improving on previous work based on Support Vector Machines achieving 91% accuracy, on an out of sample dataset of high school and collegiate football head impacts. The integrated MiG2.0 and FITBIR system serve as a collaborative research tool to be disseminated across multiple institutions towards creating a standardized dataset for furthering the knowledge of concussion biomechanics.

    View details for DOI 10.1038/s41598-021-87085-2

    View details for PubMedID 33820939

  • Compensation of physiological motion enables high-yield whole-cell recording in vivo JOURNAL OF NEUROSCIENCE METHODS Stoy, W. M., Yang, B., Kight, A., Wright, N. C., Borden, P. Y., Stanley, G. B., Forest, C. R. 2021; 348: 109008


    Whole-cell patch-clamp recording in vivo is the gold-standard method for measuring subthreshold electrophysiology from single cells during behavioural tasks, sensory stimulations, and optogenetic manipulation. However, these recordings require a tight, gigaohm resistance, seal between a glass pipette electrode's aperture and a cell's membrane. These seals are difficult to form, especially in vivo, in part because of a strong dependence on the distance between the pipette aperture and cell membrane.We elucidate and utilize this dependency to develop an autonomous method for placement and synchronization of pipette's tip aperture to the membrane of a nearby, moving neuron, which enables high-yield seal formation and subsequent recordings deep in the brain of the living mouse.This synchronization procedure nearly doubles the reported gigaseal yield in the thalamus (>3 mm below the pial surface) from 26 % (n = 17/64) to 48 % (n = 32/66). Whole-cell recording yield improved from 10 % (n = 9/88) to 24 % (n = 18/76) when motion compensation was used during the gigaseal formation. As an example of its application, we utilized this system to investigate the role of the sensory environment and ventral posterior medial region (VPM) projection synchrony on intracellular dynamics in the barrel cortex.Current methods of in vivo whole-cell patch clamping do not synchronize the position of the pipette to motion of the cell.This method results in substantially greater subcortical whole-cell recording yield than previously reported and thus makes pan-brain whole-cell electrophysiology practical in the living mouse brain.

    View details for DOI 10.1016/j.jneumeth.2020.109008

    View details for Web of Science ID 000611826600004

    View details for PubMedID 33242530

    View details for PubMedCentralID PMC7869963

  • Enabling In-Bore MRI-Guided Biopsies With Force Feedback IEEE TRANSACTIONS ON HAPTICS Frishman, S., Kight, A., Pirozzi, I., Coffey, M. C., Daniel, B. L., Cutkosky, M. R. 2020; 13 (1): 159–66


    Limited physical access to target organs of patients inside an MRI scanner is a major obstruction to real-time MRI-guided interventions. Traditional teleoperation technologies are incompatible with the MRI environment and although several solutions have been explored, a versatile system that provides high-fidelity haptic feedback and access deep inside the bore remains a challenge. We present a passive and nearly frictionless MRI-compatible hydraulic teleoperator designed for in-bore liver biopsies. We describe the design components, characterize the system transparency, and evaluate the performance with a user study in a laboratory and a clinical setting. The results demonstrate % difference between input and output forces during realistic manipulation. A user study with participants conducting mock needle biopsy tasks indicates that a remote operator performs equally well when using the device as when holding a biopsy needle directly in hand. Additionally, MRI compatibility tests show no reduction in signal-to-noise ratio in the presence of the device.

    View details for DOI 10.1109/TOH.2020.2967375

    View details for Web of Science ID 000521334300023

    View details for PubMedID 31976906

  • A Methodology for Individual-Specific Modeling of Rat Optic Nerve Head Biomechanics in Glaucoma JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME Schwaner, S. A., Kight, A. M., Perry, R. N., Pazos, M., Yang, H., Johnson, E. C., Morrison, J. C., Burgoyne, C. F., Ethier, C. 2018; 140 (8)


    Glaucoma is the leading cause of irreversible blindness and involves the death of retinal ganglion cells (RGCs). Although biomechanics likely contributes to axonal injury within the optic nerve head (ONH), leading to RGC death, the pathways by which this occurs are not well understood. While rat models of glaucoma are well-suited for mechanistic studies, the anatomy of the rat ONH is different from the human, and the resulting differences in biomechanics have not been characterized. The aim of this study is to describe a methodology for building individual-specific finite element (FE) models of rat ONHs. This method was used to build three rat ONH FE models and compute the biomechanical environment within these ONHs. Initial results show that rat ONH strains are larger and more asymmetric than those seen in human ONH modeling studies. This method provides a framework for building additional models of normotensive and glaucomatous rat ONHs. Comparing model strain patterns with patterns of cellular response seen in studies using rat glaucoma models will help us to learn more about the link between biomechanics and glaucomatous cell death, which in turn may drive the development of novel therapies for glaucoma.

    View details for DOI 10.1115/1.4039998

    View details for Web of Science ID 000462361100016

    View details for PubMedID 30003249

    View details for PubMedCentralID PMC6056184