Nanocomposite Materials For Multimodality Imaging For Use In Minimally-Invasive Surgery

Lead Research Organisation: University College London
Department Name: Medical Physics and Biomedical Eng

Abstract

The project primarily is focussing on integrating a coating onto the distal end of an optical fibre. The functionalised probe will perform multiple modes of imaging such as ultrasound imaging and photoacoustic imaging. These imaging probes can then be inserted into catheters and needles which are used in minimally-invasive surgery. The surgeon is thus able to operate with more care and precision preventing any clinical errors from occurring.


The detailed nature of the fibre coating involves a mixture of nanoparticles embedded within an elastomer. The nanoparticles are QDs which have a narrow absorption band which can be tailored by altering the size of the QDs.


Previous research has focussed purely on fabricating fibres for single-modality imaging however these probes will be among the first multimodality imaging probes to be used in minimally-invasive surgery. In addition, the formation of imaging probes using QDs is a first in this field.
 
Description During my iCase Ph.D. studentship sponsored by Johnson Matthey Ltd, I have created a fabrication scheme for a novel nanocomposite composed of CuInS2 quantum dots embedded within a polydimethylsiloxane elastomer (CIS-PDMS). The CIS-PDMS nanocomposite was deployed onto the distal end of an optical fibre which, under illumination from a 532 nm laser, produced ultrasound featuring high pressures and wide bandwidths. Due to the narrow absorption profile of the CIS quantum dots, the nanocomposite facilitated both optical ultrasound and photoacoustic imaging, an example of multimodality imaging. The nanocomposite imaged a gel-wax ink phantom recording both ultrasound and photoacoustic images.

In addition, a separate nanocomposite composed of candle-soot nanoparticles integrated within PDMS (CSNP-PDMS) was fabricated with a previously unseen one-step method. Along with a separate fabrication strategy, both these nanocomposites were deposited onto an optical fibre where high ultrasound pressures and wide bandwidths were measured providing promise for high-resolution ultrasound imaging at high penetration depths. We have conducted ultrasound imaging of lamb brain and kidney tissue using the CSNP-PDMS nanocomposites deployed onto fiber-optic end-faces.

Furthermore, we are developing gel-wax-like polymers whose set and disclosed recipes will hopefully offer researchers standardized phantoms to measure the capabilities of their imaging devices.
Exploitation Route Other nanoparticles and dyes could be incorporated with polymers including PDMS to try and generate other multimodality composites, deposited on both large planar and microscopic fiber-optic end-faces. In addition, by employing other forms of PDMS with high transparency both optically and at higher wavelengths to mix with optical absorber particles, composites with narrow absorption spectra may be developed which could be suited for various multimodality imaging applications.
Sectors Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology
 
Description This studentship is conducted in collaboration with Johnson Matthey Ltd who are sponsoring the project as part of the iCase studentship. 
Organisation Johnson Matthey
Department Johnson Matthey Technology Centre
Country United Kingdom 
Sector Private 
PI Contribution Our group at UCL have carried out research on a number of fibre-optic nanocomposites detailing reports and presentations which describe these findings as well as supplying Johnson Matthey with samples for characterisation. In addition, planar coatings deployed onto glass substrates have been studied extensively for the purposes of ex-vivo optical ultrasound and photoacoustic imaging of biological tissue.
Collaborator Contribution Johnson Matthey Ltd has provided expert advice and guidance for the project's direction and progress as well as state-of-the-art facilities and services for material supplies and sample characterisation. Examples of materials supplied by Johnson Matthey include CuInS2 quantum dots and the characterisation services which have been used by the student include scanning electron microscopes, transmission electron microscopes, and focussed ion beam technology.
Impact Fibre-optic multimodality transducers featuring optical ultrasound and photoacoustic imaging have been fabricated which have imaged a gel-wax phantom whose details were resolvable in the overlaid image of both modalities. These nanocomposites feature copper-indium-sulfide (CuInS) quantum dots (CIS QDs) embedded within a polydimethylsiloxane (PDMS) elastomeric network. These are the first nanocomposites of this kind to demonstrate multimodality imaging as well as containing such a high concentration of CIS QDs within a micro-scale substrate. In addition, fibre-optic Optical ultrasound transmitters composed of candle-soot nanoparticles encapsulated within PDMS have been created which have demonstrated high ultrasound pressures of above 3 megapascals and bandwidths beyond 30 megahertz. These transmitters have been fabricated using two methods, one completely novel to this type of nanocomposite. These transmitters are a cheaper and safer alternative to other optical ultrasound transmitters which feature toxic nanoparticles which require complex functionalisation steps to incorporate them into PDMS.
Start Year 2018
 
Description Science Museum Half-Term Outreach for School Students 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact A number of colleagues from our department at the Wellcome / EPSRC Centre for Interventional and Surgical Sciences created a stall located in the science museum to present the work that is carried out within the department. It featured materials and devices used in explanations of what work the centre carries out as well as demonstrations of how the probes work featuring explanations using non-technical terms suitable for the general public and schoolchildren.
Year(s) Of Engagement Activity 2020
 
Description Science Museum Lates 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact As part of the science museum lates, our group at UCL presented their work in optical ultrasound imaging featuring the ultrasound imaging probes, materials, and phantoms for use in imaging. We were stationed on a stall and interacted with the public explaining our work, the aims, and the future directions of our research.
Year(s) Of Engagement Activity 2020
 
Description Science of Surgery 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact As part of an open day put on by the Wellcome / EPSRC Centre for Interventional and Surgical Sciences to enable schoolchildren from local schools to better understand what work is carried out at the centre as well as to explain the basic principles of surgery. Our research group featured a small stall that contained a number of activities and games which engaged the children and showed them some of the surgical techniques used by surgeons as well as the equipment used to manufacture the imaging probes primarily devised within our group.
Year(s) Of Engagement Activity 2019