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Supplementary Design and Circuit Files Prepared for the JoVe manuscript titled “Mechanical interventions during early cardiovascular development in the avian embryo - Left Atrial Ligation Model” by Bortecine Sevgin, Merve Nur Coban, Faruk Karatas, Kerem Pekkan

Blood oxygenators involve a complex network of hollow fibers for efficient gas exchange with blood. The optimal microstructural arrangement of these fibers is an ongoing research interest. While the fiber systems of commercial oxygenators are manufactured to address mass production, the research oxygenator prototypes demand more flexibility so that different design parameters can be tested. Here a hollow-fiber assembly system is designed and built for winding research grade extracorporeal blood oxygenator mandrels at different layout dimensions so that these different configurations can be evaluated for mass transfer capacity and blood damage. The hardware design and manufacturing details of this system presented together with its impact on the prototype oxygenator device assembly process. This in-house built system can wind thin fibers, having outer diameters ranging from 100 m to 1 mm, at any specified winding angle continuously. A control system for fiber stress is also incorporated to eliminate fiber damage. Our system consists of three main units: (1) unwinding, (2) accumulator, and (3) winding systems, integrated together via the control software. The unwinding unit has a PID controller to maintain the position of the accumulator motor on the reference point by tuning the velocity of feeding fibers to the accumulator unit. Another PID controller tries to preserve the desired tension value of the fibers by adjusting the position of the accumulator motor. Desired tension value is defined by the user and typically obtained through uniaxial testing of fibers. The control unit employs a “cascaded” PID controller since the PID controller in the accumulator unit maintains the tension and the PID controller in the unwinding unit controls the position of the accumulator motor. Finally, the winding unit utilizes two motors to wind the fibers over the outer diameter of a mandrel at the desired winding angle. The first motor drives the translational movement, and the second one provides mandrel rotation. The desired angles are achieved by tuning the synchronous movement of the winding motors. While the system is designed to produce assembled blood oxygenator mandrel prototypes, this concept is also applicable for producing cylindrical fiber-reinforced composite materials with specified fiber angles and stents winded on jigs., Funding was provided by research grants from the European Research Council (ERC) Proof of Concept BloodTurbine, TUBITAK 118S108 and BİDEB - 2247A - 120C139 (PI: Kerem Pekkan).

The hardware design and manufacturing of a low-cost tension-controlled hollow fiber winding machine prototype is presented. This in-house built system can wind thin fibers, having outer diameters ranging from 100 umto 1 mm, at any specified angle continuously. A control system for fiber stress is also incorporated to eliminate fiber damage. The system is designed for winding research grade extracorporeal blood oxygenator mandrels at different layout dimensions so that these different configurations can be evaluated for mass transfer capacity and blood damage. While the system is designed to produce assembled blood oxygenator mandrel prototypes, it is also applicable for producing similar composite materials with specified fiber angles. Our system consists of three main units: (1) unwinding, (2) accumulator, and (3) winding systems and control software. The unwinding unit has a PID controller to maintain the position of the accumulator motor on the reference point by tuning the velocity of feeding fibers to the accumulator unit. Another PID controller tries to preserve the desired tension value of the fibers by adjusting the position of the accumulator motor. Desired tension value is defined by the user and typically obtained through uniaxial testing of fibers. The control unit employs a “cascaded” PID controller since the PID controller in the accumulator unit maintains the tension and the PID controller in the unwinding unit controls the position of the accumulator motor. Finally, the winding unit utilizes two motors to wind the fibers on a mandrel at the desired winding angle. The first motor makes a translational movement, and the second one rotates the mandrel. The desired angles are achieved by tuning the synchronous movement of the winding motors.

Mechanical circulatory support (MCS) is used as a bridge-to-heart transplantation for end-stage failing Fontan patients with single-ventricle (SV) circulation. Donor shortage and complexity of the single-ventricle circulation physiology demands novel circulatory support systems and alternative solutions. An out-of-the-box circulation concept in which the left and right ventricles are switched with each other inspired a novel bi-ventricle MCS configuration for the “failing” Fontan patients. In the proposed configuration, the systemic circulation is maintained by a conventional mechanical ventricle assist device while the venous circulation is delegated to the native SV. This approach spares the SV and puts it to a new use at the right-side providing the most needed venous flow pulsatility. To analyze its feasibility and performance, 8 realistic Fontan circulation scenarios have been studied via a multi-compartmental lumped parameter cardiovascular model (LPM). Model is developed specifically for simulating the SV circulation and validated against pulsatile mock-up flow loop measurements for the ideal (Fontan), failed (VD) and assisted Fontan (PVR-cmcs) scenarios. The proposed surgical configuration maintained the cardiac index (3-3.5 l/min/m2) providing a normal mean systemic arterial pressure. For a failed SV with low ejection fraction (EF=26%), representing a typical systemic failure, proposed configuration introduced a venous/pulmonary pulsatility of ∼28 mmHg and a drop of 2 mmHg in central venous pressure (CVP) with acceptable pulmonary artery pressures (17.5 mmHg). In the pulmonary vascular resistance (PVR) failure model, it provided approximately 5 mmHg drop in CVP with venous/pulmonary pulsatility reaching ∼22 mmHg. For high PVR failure case with a healthy SV (EF = 44%) pulmonary hypertension is likely to occur, indicating a need for precise functional assessment of the failed-ventricle before it is considered for the proposed arrangement. Comprehensivein vitroandin silicoresults encourage this concept as an economical alternative to the conventional bi-ventricle MCS pending animal experiments.