Towards the long-term implantation of the quick to implant peripheral intraneural electrode (Q-PINE)

Vagus nerve dysfunctions are associated with pathologies related to many organs, like heart failure (HF), obesity, and mood disorders. A possible treatment is proposed by bioelectronic medicine. This research field focuses on the electrical stimulation of the nerves, trying to restore their physiological functions. The devices used are called neural interfaces. For the vagus nerve, this therapy is called vagus nerve stimulation (VNS). Current technologies for VNS involve extraneural approaches, which are devices that enwrap the nerve inducing electrical pulses from the outside. However, those have many problems related to adverse effects, due to their low selectivity. Intraneural approaches have been proposed to overcome those limitations. The focus of this work is the increasing of the long-term biocompatibility of the Q-PINE, an intraneural electrode used for the vagus nerve, to be used in chronic implants. The components of the Q-PINE have been analysed, together with the materials used, and a new design has been realised. Then, a material study was performed to identify suitable biomaterials for long-term applications in neuroprostheses. These material are liquid crystal polymers (LCP), polyimide (PI) and polyetheretherketone (PEEK). Among these, PEEK was selected for the new version of the Q-PINE. Moreover, also the glues holding together different components of the Q-PINE have been substituted with UV biocompatible glues certified by ISO standards. Mechanical tests were performed to evaluate the forces involved in the implantation procedure. The results suggest that PEEK is a feasible choice since it does not alter the implantation mechanics and increases the possibility of the Q-PINE to be used in long-term applications

Adaptation and Optimization of an Intraneural Electrode to Interface with the Cervical Vagus Nerve

The modulation of the cervical vagus nerve (VN) using neural electrodes has shown great potential to treat cardiovascular, inflammatory, intestinal, or respiratory dysfunctions. Intraneural electrodes have shown great potentials for other neuroprosthetic applications. Therefore, their use for VN modulation could have great potential. Here we optimized an intraneural electrode originally developed for use in lower limb amputees. Based on histological data from the VN of 100 histological sections we adapted and optimized the dimensions of the Quick-to-implant peripheral neural electrode (Q-PINE). Parts of the Q- PINE were substituted to increase biocompatibility. The platinum-iridium (Pt/Ir) wires were substituted with a polyimide thin-film structure to optimize the electrodes' impedance. Mechanical and electrochemical characterization was performed to exclude negative alterations resulting from the design and material changes. The dimensional adaptation and material substitutions of the Q- PINE did not alter its mechanical or electrochemical properties. The tfQPINE shows promising results for the successful application with the VN

Left cardiac vagotomy rapidly reduces contralateral cardiac vagal electrical activity in anesthetized Göttingen minipigs

Background: The impact of acute unilateral injury on spontaneous electrical activity in both vagus nerves at the heart level is poorly understood. We investigated the immediate neuroelectrical response after right or left cardiac vagal nerve transection (VNTx) by recording spiking activity of each heart vagus nerve (VN). Methods: Fourteen male Göttingen minipigs underwent sternotomy. Multi-electrode cuffs were implanted below the cut level to record vagal electroneurographic signals during electrocardiographic and hemodynamic monitoring, before and immediately after cardiac VNTx (left: L-cut, n = 6; right: R-cut, n = 8). Results: Left cardiac VNTx significantly reduced multi-unit electrical activity (MUA) firing rate in the vagal stump (-30.7% vs pre-cut) and intact right VN (-21.8% vs pre-cut) at the heart level, without affecting heart rate, heart rate variability, or hemodynamics. In contrast, right cardiac VNTx did not acutely alter MUA in either VN but slightly increased (p < 0.022) the root mean square of successive RR interval differences (rMSSD), an index of parasympathetic outflow, without affecting hemodynamics. Conclusions: Our study reveals an early left-lateralized pattern in vagal spiking activity following unilateral cardiac vagotomy. These findings enhance understanding of the neuroelectrical response to vagal injury and provide insights into preserving vagal outflow after unilateral cardiac vagotomy. Importantly, monitoring spiking activity of the cardiac right VN may predict onset of left vagal pathway injury, which is detrimental to cardiac patients and can occur as a complication of catheter ablation for atrial fibrillation

Additional file 1 of A soft, scalable and adaptable multi-contact cuff electrode for targeted peripheral nerve modulation

Additional file 1

Implantable Fiber Bragg Grating sensor for continuous heart activity monitoring: ex-vivo and in-vivo validation

Continuous and reliable cardiac function monitoring could improve medication adherence in patients at risk of heart failure. This work presents an innovative implantable Fiber Bragg Grating-based soft sensor designed to sense mechanical cardiac activity. The sensor was tested in an isolated beating ovine heart platform, with 3 different hearts operated in wide-ranging conditions. In order to investigate the sensor capability to track the ventricular beats in real-time, two causal algorithms were proposed for detecting the beats from sensor data and to discriminate artifacts. The first based on dynamic thresholds while the second is a hybrid convolutional and recurrent Neural Network. An error of 2.7 ± 0.7 beats per minute was achieved in tracking the heart rate. Finally, we have confirmed the sensor reliability in monitoring the heart activity of healthy adult minipig with an error systematically lower than 1 Bpm