Robotics and Artificial Intelligence in Endovascular Neurosurgery.

The use of artificial intelligence (AI) and robotics in endovascular neurosurgery promises to transform neurovascular care. We present a review of the recently published neurosurgical literature on artificial intelligence and robotics in endovascular neurosurgery to provide insights into the current advances and applications of this technology. The PubMed database was searched for "neurosurgery" OR "endovascular" OR "interventional" AND "robotics" OR "artificial intelligence" between January 2016 and August 2021. A total of 1296 articles were identified, and after applying the inclusion and exclusion criteria, 38 manuscripts were selected for review and analysis. These manuscripts were divided into four categories: 1) robotics and AI for the diagnosis of cerebrovascular pathology, 2) robotics and AI for the treatment of cerebrovascular pathology, 3) robotics and AI for training in neuroendovascular procedures, and 4) robotics and AI for clinical outcome optimization. The 38 articles presented include 23 articles on AI-based diagnosis of cerebrovascular disease, 10 articles on AI-based treatment of cerebrovascular disease, two articles on AI-based training techniques for neuroendovascular procedures, and three articles reporting AI prediction models of clinical outcomes in vascular disorders of the brain. Innovation with robotics and AI focus on diagnostic efficiency, optimizing treatment and interventional procedures, improving physician procedural performance, and predicting clinical outcomes with the use of artificial intelligence and robotics. Experimental studies with robotic systems have demonstrated safety and efficacy in treating cerebrovascular disorders, and novel microcatheterization techniques may permit access to deeper brain regions. Other studies show that pre-procedural simulations increase overall physician performance. Artificial intelligence also shows superiority over existing statistical tools in predicting clinical outcomes. The recent advances and current usage of robotics and AI in the endovascular neurosurgery field suggest that the collaboration between physicians and machines has a bright future for the improvement of patient care. The aim of this work is to equip the medical readership, in particular the neurosurgical specialty, with tools to better understand and apply findings from research on artificial intelligence and robotics in endovascular neurosurgery.

Vacuum exhausted isolation locker (VEIL) to reduce inpatient droplet/aerosol transmission during COVID-19 pandemic.

The vacuum-exhausted isolation locker (VEIL) provides a safety barrier during the care of COVID-19 patients. The VEIL is a 175-L enclosure with exhaust ports to continuously extract air through viral particle filters connected to hospital suction. Our experiments show that the VEIL contains and exhausts exhaled aerosols and droplets.

Soft robotic steerable microcatheter for the endovascular treatment of cerebral disorders.

Catheters used for endovascular navigation in interventional procedures lack dexterity at the distal tip. Neurointerventionists, in particular, encounter challenges in up to 25% of aneurysm cases largely due to the inability to steer and navigate the tip of the microcatheters through tortuous vasculature to access aneurysms. We overcome this problem with submillimeter diameter, hydraulically actuated hyperelastic polymer devices at the distal tip of microcatheters to enable active steerability. Controlled by hand, the devices offer complete 3D orientation of the tip. Using saline as a working fluid, we demonstrate guidewire-free navigation, access, and coil deployment in vivo, offering safety, ease of use, and design flexibility absent in other approaches to endovascular intervention. We demonstrate the ability of our device to navigate through vessels and to deliver embolization coils to the cerebral vessels in a live porcine model. This indicates the potential for microhydraulic soft robotics to solve difficult access and treatment problems in endovascular intervention.

Microliter ultrafast centrifuge platform for size-based particle and cell separation and extraction using novel omnidirectional spiral surface acoustic waves.

Asymmetric surface acoustic waves have been shown useful in separating particles and cells in many microfluidics designs, mostly notably sessile microdroplets. However, no one has successfully extracted target particles or cells for later use from such samples. We present a novel omnidirectional spiral surface acoustic wave (OSSAW) design that exploits a new cut of lithium niobate, 152 Y-rotated, to rapidly rotate a microliter sessile drop to ∼10 g, producing efficient multi-size particle separation. We further extract the separated particles for the first time, demonstrating the ability to target specific particles, for example, platelets from mouse blood for further integrated point-of-care diagnostics. Within ∼5 s of surface acoustic wave actuation, particles with diameter of 5 µm and 1 µm can be separated into two portions with a purity of 83% and 97%, respectively. Red blood cells and platelets within mouse blood are further demonstrated to be separated with a purity of 93% and 84%, respectively. These advancements potentially provide an effective platform for whole blood separation and point-of-care diagnostics without need for micro or nanoscale fluidic enclosures.

Facile Analytical Extraction of the Hyperelastic Constants for the Two-Parameter Mooney-Rivlin Model from Experiments on Soft Polymers.

Having accurate data to represent hyperelastic materials that underpin soft robotics would facilitate their analysis, design, and validation. We seek to provide the reader with a useful tool to overcome a mundane but crucially important problem in determining the hyperelastic material properties. We show how to employ first dimensionless and then dimensional comparisons between experimental data and the classic theoretical model representing this system to produce C1 and C2 for the Mooney-Rivlin model, closely representing a variety of soft polymers.

Rapid and Accurate Pressure Sensing Device for Direct Measurement of Intraocular Pressure.

Purpose: Intraocular pressure (IOP) is the primary modifiable risk factor for glaucoma. Current devices measure IOP via the dynamic response of the healthy cornea and do not provide the accurate IOP measurements for patients with altered corneal biomechanics. We seek to develop and test an accurate needle-based IOP measurement device that is not cornea dependent. Methods: Our device combines a high-resolution pressure microsensor with 30- and 33-gauge Luer lock needles to provide IOP measurements via a microcontroller and USB interface to a computer. The device was calibrated in a membrane chamber and then tested and validated in the anterior chamber and post-vitrectomy vitreous chamber of rabbit eyes. The results were compared to Tonopen readings across a pressure range of 0 to 100 mm Hg, imposed in increments of 10 mm Hg. Results: Both the needle based sensor device and the Tonopen demonstrated a linear relationship with changes in imposed pressure. The Tonopen was found to consistently underestimate the IOP both in the anterior and vitreous chambers. The Tonopen exhibited a significantly greater error than our needle-based sensor device. With increased pressure (>30 mm Hg), the error of the Tonopen increased, whereas the error of our device did not. The 30-gauge needle produces an insignificant improvement in accuracy over the 33-gauge needle. Conclusions: A needle-based sensor device enables accurate IOP measurements over a broad range of induced IOP. Translational Relevance: Direct measurement of IOP in the anterior chamber circumvents the influence of corneal parameters on IOP measurement.

Optimized, Omnidirectional Surface Acoustic Wave Source: 152° Y-Rotated Cut of Lithium Niobate for Acoustofluidics.

Here, we propose an optimized Y -rotated cut of lithium niobate (LN) for multidirectional surface acoustic wave (SAW) propagation, simultaneously minimizing the anisotropic effects while maximizing the electromechanical properties of this cut of LN. The goal is to offer a piezoelectric material suitable for acoustofluidics applications that require greater flexibility in wave generation and propagation than the currently ubiquitous 128° Y -rotated X -propagating cut. The 128YX LN cut is known to most effectively generate Rayleigh SAW along the x -direction alone. Any SAW veering from this propagation direction is affected by beam steering and changes in resonance frequency and electromechanical coupling coefficients, consequently limiting the use of LN in various acoustofluidics applications, where more diverse configurations would be beneficial. The L2 -norm of these properties was evaluated under rotational transformation to produce a physical model with closed governing equations for 40-MHz surface wave propagation on the surface of a piezoelectric material. This was then utilized to obtain the surface wave velocity and coupling coefficient of the specific Y -cut LN with respect to the propagating direction. Next, the averaged coupling coefficients of various Y -cuts of LN in all propagating directions were calculated and integrated to simultaneously minimize anisotropy and maximize the electromechanical properties of the LN substrate. A 152° Y -rotated cut was found to be the optimal choice under these constraints, enabling multidirectional SAW propagation with greater coupling and lower variation in wave performance for SAW generated across the surface in any direction. Compared with the 128YX LN cut, this cut provides a 66.5% improvement in the in-plane isotropy and a 37.0% improvement in the average electromechanical coupling for in-plane SAW propagation. Experimental devices operating at the frequency of 40 MHz were designed, fabricated, and tested on the surface of this 500- [Formula: see text]-thick specific cut of LN and served to verify the supporting analysis and the superior isotropic properties of the 152° Y -rotated cut in generating SAW.

Micro/nano acoustofluidics: materials, phenomena, design, devices, and applications.

Acoustic actuation of fluids at small scales may finally enable a comprehensive lab-on-a-chip revolution in microfluidics, overcoming long-standing difficulties in fluid and particle manipulation on-chip. In this comprehensive review, we examine the fundamentals of piezoelectricity, piezoelectric materials, and transducers; revisit the basics of acoustofluidics; and give the reader a detailed look at recent technological advances and current scientific discussions in the discipline. Recent achievements are placed in the context of classic reports for the actuation of fluid and particles via acoustic waves, both within sessile drops and closed channels. Other aspects of micro/nano acoustofluidics are examined: atomization, translation, mixing, jetting, and particle manipulation in the context of sessile drops and fluid mixing and pumping, particle manipulation, and formation of droplets in the context of closed channels, plus the most recent results at the nanoscale. These achievements will enable applications across the disciplines of chemistry, biology, medicine, energy, manufacturing, and we suspect a number of others yet unimagined. Basic design concepts and illustrative applications are highlighted in each section, with an emphasis on lab-on-a-chip applications.

Motility induced changes in viscosity of suspensions of swimming microbes in extensional flows.

Suspensions of motile cells are model systems for understanding the unique mechanical properties of living materials which often consist of ensembles of self-propelled particles. We present here a quantitative comparison of theory against experiment for the rheology of such suspensions in extensional flows. The influence of motility on viscosities of cell suspensions is studied using a novel acoustically-driven microfluidic capillary-breakup extensional rheometer. Motility increases the extensional viscosity of suspensions of algal pullers, but decreases it in the case of bacterial or sperm pushers. A recent model [Saintillan, Phys. Rev. E: Stat., Nonlinear, Soft Matter Phys., 2010, 81, 56307] for dilute active suspensions is extended to obtain predictions for higher concentrations, after independently obtaining parameters such as swimming speeds and diffusivities. We show that details of body and flagellar shape can significantly determine macroscale rheological behaviour.