Showing papers by "Nigel H. Lovell published in 2023"

Advanced Soft Robotic System for In Situ 3D Bioprinting and Endoscopic Surgery

Abstract: Three‐dimensional (3D) bioprinting technology offers great potential in the treatment of tissue and organ damage. Conventional approaches generally rely on a large form factor desktop bioprinter to create in vitro 3D living constructs before introducing them into the patient's body, which poses several drawbacks such as surface mismatches, structure damage, and high contamination along with tissue injury due to transport and large open‐field surgery. In situ bioprinting inside a living body is a potentially transformational solution as the body serves as an excellent bioreactor. This work introduces a multifunctional and flexible in situ 3D bioprinter (F3DB), which features a high degree of freedom soft printing head integrated into a flexible robotic arm to deliver multilayered biomaterials to internal organs/tissues. The device has a master‐slave architecture and is operated by a kinematic inversion model and learning‐based controllers. The 3D printing capabilities with different patterns, surfaces, and on a colon phantom are also tested with different composite hydrogels and biomaterials. The F3DB capability to perform endoscopic surgery is further demonstrated with fresh porcine tissue. The new system is expected to bridge a gap in the field of in situ bioprinting and support the future development of advanced endoscopic surgical robots.

Advanced User Interfaces for Teleoperated Surgical Robotic Systems

Abstract: In recent years, advances in modern technology have altered the practice of surgery from open to minimally invasive surgery (MIS) aided by robots. Teleoperated surgical robotic systems (TSRSs) provide numerous significant benefits for MIS over traditional approaches, including improved safety, more efficient and precise surgery, better cosmesis, shorter recovery time, and reduced postoperative pain. Existing TSRSs’ master consoles, with improvements in vision systems, designs, and control methods, have significantly enhanced human–robot interactions, resulting in safer and more accurate medical intervention operations. Despite advances, haptic technologies, including sensors, machine assistance, and intuitive devices for user interfaces, are still limited, resulting in less effective usage of TSRSs for surgical operations. This review presents a summary of the emerging TSRSs with a focus on their user interfaces. In addition, advanced sensing, haptic, smart garments, and medical image artificial intelligence (AI) assistance technologies are shown with their potential for use in master consoles of the TSRSs are shown. Finally, a discussion on the need for a smart human‐robot interface for TSRSs is given.

A Handheld Hydraulic Soft Robotic Device with Bidirectional Bending End-Effector for Minimally Invasive Surgery

Abstract: Minimally invasive surgery (MIS) has evolved as an effective method for cardiovascular diseases (CVDs) and gastrointestinal (GI) cancers. Recently, soft robotic catheters using soft materials have attracted considerable attention thanks to their ability to navigate through intricate anatomical structures and perform precisely controlled movements. However, current systems are powered by rigid pull-wire mechanism, showing substantial nonlinear hysteresis and high force loss. Furthermore, they require several actuators to manipulate the bending tip for working in the intricate anatomical corners of the internal organs. For thrombus removal, the approach of stent retrieval via a catheter has various drawbacks including difficult manipulation, insufficient retrieval force, and complexity. Herein, new soft robotic catheters are introduced to address these challenges. The new catheters can achieve bidirectional bending motion and spiral shapes using a single soft actuation source. They are equipped with a portable and ergonomic control interface. Mathematical models for the bending effector are developed and experimentally validated. The new soft robotic catheters potentially allow for quicker and more accurate manipulation to reach any target inside the cardiac and GI regions, enabling faster and more targeted ablation and thrombus removal therapy to enhance patient outcomes.

Bio-SHARPE: Bioinspired Soft and High Aspect Ratio Pumping Element for Robotic and Medical Applications.

Abstract: The advent of soft robots has solved many issues posed by their rigid counterparts, including safer interactions with humans and the capability to work in narrow and complex environments. While much work has been devoted to developing soft actuators and bioinspired mechatronic systems, comparatively little has been done to improve the methods of actuation. Hydraulically soft actuators (HSAs) are emerging candidates to control soft robots due to their fast responses, low noise, and low hysteresis compared to compressible pneumatic ones. Despite advances, current hydraulic sources for large HSAs are still bulky and require high power availability to drive the pumping plant. To overcome these challenges, this work presents a new bioinspired soft and high aspect ratio pumping element (Bio-SHARPE) for use in soft robotic and medical applications. This new soft pumping element can amplify its input volume to at least 8.6 times with a peak pressure of at least 40 kPa. The element can be integrated into existing hydraulic pumping systems like a hydraulic gearbox. Naturally, an amplification of fluid volume can only come at the sacrifice of pumping pressure, which was observed as a 19.1:1 reduction from input to output pressure. The new concept enables a large soft robotic body to be actuated by smaller fluid reservoirs and pumping plant, potentially reducing their power and weight, and thus facilitating drive source miniaturization. The high amplification ratio also makes soft robotic systems more applicable for human-centric applications such as rehabilitation aids, bioinspired untethered soft robots, medical devices, and soft artificial organs. Details of the fabrication and experimental characterization of the Bio-SHARPE and its associated components are given. A soft robotic squid and an artificial heart ventricle are introduced and experimentally validated.

Engineering Route for Stretchable, 3D Microarchitectures of Wide Bandgap Semiconductors for Biomedical Applications

Abstract: Wide bandgap (WBG) semiconductors have attracted significant research interest for the development of a broad range of flexible electronic applications, including wearable sensors, soft logical circuits, and long-term implanted neuromodulators. Conventionally, these materials are grown on standard silicon substrates, and then transferred onto soft polymers using mechanical stamping processes. This technique can retain the excellent electrical properties of wide bandgap materials after transfer and enables flexibility; however, most devices are constrained by 2D configurations that exhibit limited mechanical stretchability and morphologies compared with 3D biological systems. Herein, a stamping-free micromachining process is presented to realize, for the first time, 3D flexible and stretchable wide bandgap electronics. The approach applies photolithography on both sides of free-standing nanomembranes, which enables the formation of flexible architectures directly on standard silicon wafers to tailor the optical transparency and mechanical properties of the material. Subsequent detachment of the flexible devices from the support substrate and controlled mechanical buckling transforms the 2D precursors of wide band gap semiconductors into complex 3D mesoscale structures. The ability to fabricate wide band gap materials with 3D architectures that offer device-level stretchability combined with their multi-modal sensing capability will greatly facilitate the establishment of advanced 3D bio-electronics interfaces.

A Flexible 3D Force Sensor with In-Situ Tunable Sensitivity

Abstract: Following biology's lead, soft robotics has emerged as a perfect candidate for actuation within complex environments. While soft actuation has been developed intensively over the last few decades, soft sensing has so far slowed to catch up. A largely unresearched area is the change of the soft material properties through prestress to achieve a degree of mechanical sensitivity tunability within soft sensors. Here, a new 3D force sensor which employs novel hydraulic filament artificial muscles capable of in-situ sensitivity tunability is introduced. Using a neural network (NN) model, the new soft 3D sensor can precisely detect external forces based on the change of the hydraulic pressures with error of $\sim 1.0, \sim 1.3$, and $\sim 0.94$ % in the $\text{x, y}$, and z-axis directions, respectively. The sensor is also able to sense large force ranges, comparable to other similar sensors available in the literature. The sensor is then integrated into a soft robotic surgical arm for monitoring the tool-tissue interaction during an ablation process.

Unobtrusive Human Fall Detection System Using mmWave Radar and Data Driven Methods

Abstract: As the population ages, health issues like injurious falls demand more attention. One solution is to use wearable devices to detect falls. Nevertheless, most of these devices raise obtrusiveness, and older people generally resist or might forget to wear them. The millimeter-wave (mmWave) radar technology was used in this study to unobtrusively detect human falls. Data were collected from healthy young volunteers with the radar mounted on the side wall (trial 1) or overhead (trial 2) of an experimental room. A set of features were manually extracted from the data point clouds; then, multilayer perceptron (MLP), random forest (RF), ${k}$ -nearest neighbor (KNN), and support vector machine (SVM) classifiers were applied on the features. Additionally, we devised a convolutional neural network (CNN)-based deep learning model for the underlying fall detection problem that receives a 3-D representation of the point cloud data, known as occupancy grid, as the input. The optimal installation position of the radar sensor was unknown. Therefore, the sensor was mounted on side wall and on the ceiling of the room to allow the performance comparison between these sensor placements. RF classifier achieved the best results in trial 2 (an accuracy of 92.2%, a recall of 0.881, a precision of 0.805, and an ${F}1$ -score of 0.841), and the proposed CNN model achieved slightly better results comparing to the RF method in trial 2 (an accuracy of 92.3%, a recall of 0.891, a precision of 0.801, and an ${F}1$ -score of 0.844). These results suggest that the development of an unobtrusive monitoring system for fall detection using mmWave radar is feasible.

Technological Convergence: Highlighting the Power of CRISPR Single-Cell Perturbation Toolkit for Functional Interrogation of Enhancers

Abstract: Higher eukaryotic enhancers, as a major class of regulatory elements, play a crucial role in the regulation of gene expression. Over the last decade, the development of sequencing technologies has flooded researchers with transcriptome-phenotype data alongside emerging candidate regulatory elements. Since most methods can only provide hints about enhancer function, there have been attempts to develop experimental and computational approaches that can bridge the gap in the causal relationship between regulatory regions and phenotypes. The coupling of two state-of-the-art technologies, also referred to as crisprQTL, has emerged as a promising high-throughput toolkit for addressing this question. This review provides an overview of the importance of studying enhancers, the core molecular foundation of crisprQTL, and recent studies utilizing crisprQTL to interrogate enhancer-phenotype correlations. Additionally, we discuss computational methods currently employed for crisprQTL data analysis. We conclude by pointing out common challenges, making recommendations, and looking at future prospects, with the aim of providing researchers with an overview of crisprQTL as an important toolkit for studying enhancers.

A Bi-Directional Detection and Stimulation Optrode System With Charge Balancing for Neural Applications

Abstract: The design of a bi-directional optical-electrode or ’optrode' for peripheral nerve and brain-machine interfacing is proposed and its principle of operation detailed, which is able to provide biphasic stimulus and charge balancing functionalities. The prototype chip is fabricated, characterised on the bench, and assessed in vivo and ex vivo. Results show that it can simultaneously stimulate and record from the rabbit sciatic nerve, and entrainment of the sino-atrial node is achieved and observed by the prototype. Then, a discrete component circuit is tested for validation of this charge-balancing effect. Experimental results from in vivo testing on rabbit sciatic nerves demonstrate that the voltage generated by photodiodes at around 0.5 to 0.6 V is able to evoke compound action potentials, and the activated light-dependent resistor removed more than 80% of the post-stimulus charge stored at the interface.

A Handheld Hydraulic Cardiac Catheter with Omnidirectional Manipulator and Touch Sensing

Abstract: Atrial fibrillation (AF) is mostly treated via robotic catheter-based cardiac ablation procedures. Over the last few decades, cables or tendon mechanisms are at the core of available cardiac catheters. Despite advances, the use of cables often results in considerable force loss, nonlinear hysteresis, and control challenges. Most catheters are not equipped with force sensing, which increases the risk of the ablation process and decreases their efficacy in clinical settings. In addition, current catheters have a poor user interface and therefore the ablation process requires skilled or trained surgeons to steer the complex motion of the catheter tip within the heart chambers. To improve the cardiac ablation procedure, a new robotic catheter that has the ability to extend its working space without moving its flexible body and a real-time force sensor for safe operation is highly desired. In this work, a new handheld and soft robotic catheter for AF ablation is introduced. The new device consists of several improved components such as a soft manipulator for navigation and bending motion, an ergonomic handheld controller, and a soft force sensor for monitoring tool-tissue contact. The design, modeling, and fabrication of the device are presented and followed by experimental characterizations and ex-vivo validation.

A Comparative Assessment of Evoked Compound Action Potentials Measured by Optrode and Conventional Bioamplifier Systems

Abstract: Reliable signal detection of biopotentials in excitable tissues has been one of the longest-standing challenges in neural and cardiac electrophysiology. While using standard electrodes and bioamplifiers provides insight into the cell activity with a high temporal resolution, electrical recording still suffers from several limitations that can hinder long-term operation and clinical translation. The recently developed liquid crystal optical-electrode or ‘optrode’ has exhibited powerful diagnostic potential for multiple applications by using light to passively sense biopotentials in a fluorophore-free manner. While it has been demonstrated that this optrode device can detect electrically evoked compound action potentials from rabbit sciatic nerves, the microvolt-level features within the response that represent different nerve fibers inside the sciatic nerve bundle have not been investigated. Herein, we report a detailed investigation of the optrode's recording performance by analyzing the conduction velocity of different detected nerve fibers. We show that the optrode can record various nerve fiber responses to electrical stimulation, including $\mathbf{A}\delta, \mathbf{B}$, and C fibers as verified by comparison to measurements via a conventional bioamplifier. We found that there are some challenges encountered when recording nerve responses of low amplitudes $\boldsymbol{(< 300 \ \mu} \mathbf{V})$ or high conduction velocities $(> 30 \ \mathrm{m}/\mathrm{s})$ using the optrode due to its limited signal-to-noise ratio and bandwidth, highlighting the necessity for design improvement.