Micro-Scale Bio-Inspired Structured Polymer Surfaces for Tissue Adhesion

There are many cases when it would be beneficial to provide reliable, reversible adhesion at a tissue-device interface. There are currently many adhesion mechanisms used during surgical procedures such as graspers, vacuum cups and hooks. However, these are known to cause some scale of tissue trauma. This thesis investigates the viability of using a bio-inspired, structured polymer surfaces to provide wet adhesion forces through the formation of liquid bridges on the tip of discrete pillars. The mechanism described involves a contribution from both Stefan forces and capillary forces to provide the total adhesion force. A main factor to this work is the ability to successfully, repeatedly and reliably fabricate polymer surfaces at a micron scale with varying geometry, specifically in terms of pillar spacing. The substrate should be flexible and have the ability to tune the wettability. A number of lithography techniques have been explored for a range of polymers, finally settling on a nano-imprint lithography technique with Poly (dimethylsiloxane) (PDMS) as the polymer. Experimental adhesion tests have been performed and it has been found, that for such an adhesion mechanism to be successful, an optimal contact angle must be reached. If the contact angle is too high, repulsive forces in convex menisci will form and the adhesion will be low as a result. If the contact angle is too low, the capillary length : pillar height ratio results in the surface acting super-hydrophobic and completely wetting the pillars, preventing the formation of liquid bridges, and again resulting in low adhesion, it is proposed that such a mechanism would occur at contact angles lower than 50°. A mathematical model has been investigated, encompassing both the Stefan and adhesion forces and the limitations of this have been discussed in relation to the complexity of this system

Development of a Novel Amphibious Locomotion System for use in Intra-Luminal Surgical Procedures

Colonoscopy is widely considered the gold standard for inspection of the colon. The procedure is however not without issue, current colonoscopes have seen little change or innovation throughout their 40 years of use with patient discomfort still limiting success. The aim of this PhD study was to develop a locomotion system for use on a robotic device that can traverse a liquid filled colon for atraumatic inspection and biopsy tasks. The PhD was undertaken as part of a larger two-centre EU project, which aimed to bring about a change in the way colonoscopy is done by moving to “robotic hydro-colonoscopy”. In this thesis the initial development and testing of an amphibious locomotion concept for use in a procedure known as hydro-colonoscopy is described. The locomotion system is comprised of four Archimedes’ screws arranged in two counter-rotating pairs. These aim to provide propulsion through a fluid-filled colon as well as provide locomotive traction against colonic tissue in partially fluid-filled or collapsed sections of the colon, such as the splenic flexure. Experimental studies were carried out on a single screw system in fluid and dual counter-rotating screws in contact conditions. These show the system’s ability to generate thrust in the two discrete modes of locomotion of the amphibious system. A 2:1 scale prototype of the proposed device was produced and features compliant screw threads to provide atraumatic locomotion. The scale prototype device was tested in ex-vivo porcine colon. The developed system was able to traverse through lumen to limited success, which demonstrated that this concept has the potential for use on an intra-luminal robotic device The key contributions of this research are: variable geometry locomotion system; amphibious locomotion using Archimedes’ screws; experimental assessment of the locomotion in fluid, contact and amphibious states; and analysis of the contact dynamics against tissue

Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

Design, manufacturing and characterisation of a wireless flexible pressure sensor system for the monitoring of the gastro-intestinal tract

Ingestible motility capsule (IMC) endoscopy holds a strong potential in providing advanced diagnostic capabilities within the small intestine with higher patient tolerance for pathologies such as irritable bowel syndrome, gastroparesis and chronic abdominal amongst others. Currently state-of-the art IMCs are limited by the use of obstructive off-the-shelf sensing modules that are unable to provide multi-site tactile monitoring of the Gastro-Intestinal tract. In this work a novel 12 mm in diameter by 30 mm in length IMC is presented that utilises custom-built flexible, thin-film, biocompatible, wireless and highly sensitive tactile pressure sensors arrays functionalising the capsule shell. The 150 μm thick, microstructured, PDMS flexible passive pressure sensors are wirelessly powered and interrogated, and are capable of detecting pressure values ranging from 0.1 kPa up to 30 kPa with a 0.1 kPa resolution. A novel bottom-up wafer-scale microfabrication process is presented which enables the development of these ultra-dense, self-aligned, scalable and uniquely addressable flexible wireless sensors with high yield (>80%). This thesis also presents an innovative metallisation microfabrication process on soft-elastomeric substrates capable to withstand without failure of the tracks 180o bending, folding and iterative deformation such as to allow conformable mapping of these sensors. A custom-built and low-cost reflectometer system was also designed, built and tested within the capsule that can provide a fast (100 ms) and accurate extraction (±0.1 kPa) of their response. In vitro and in vivo characterisation of the developed IMC device is also presented, facilitated respectively via the use of a biomimetic phantom gut and via live porcine subjects. The capsule device was found to successfully capture respiration, low-amplitude and peristaltic motility of the GI tract from multiple sites of the capsule.UK Engineering & Physical Sciences Research Council (EPSRC) through the Programme Grant Sonopill (EP/K034537/2)James Watt Scholarshi

Textbook of Plastic and Reconstructive Surgery

Written by experts from London’s renowned Royal Free hospital, Textbook of Plastic and Reconstructive Surgery offers a comprehensive overview of the vast topic of reconstructive plastic surgery and its various subspecialties for introductory plastic surgery and surgical science courses. The book comprises five sections covering the fundamental principles of plastic surgery, cancer, burns and trauma, paediatric plastic surgery and aesthetic surgery, and covers the breadth of knowledge that students need to further their career in this exciting field. Additional coverage of areas in which reconstructive surgery techniques are called upon includes abdominal wall reconstruction, ear reconstruction and genital reconstruction. A section on aesthetic surgery includes facial aesthetic surgery and blepharoplasty, aesthetic breast surgery, body contouring and the evolution of hair transplantation. The broad scope of this volume makes this a unique contribution to the field.Heavily illustrated throughout, Textbook of Plastic and Reconstructive Surgery is essential reading for anyone interested in furthering their knowledge of this exciting field