Biomedical

Professor Stokes lead’s the group’s activity in Biomedical Enginering and Bioelectronics. We are exploring fundamentals and applications of the intersections between electronics, biology, and fluidic systems. The intersection of the world of hard things with the world of soft things, the world that we make with the world that makes itself.

The highly integrated systems that we are building have applications in robotics, medical devices, research-in-space, high-throughput biotechnology and diagnostics.

High-Throughput Microfluidics for Biotechnology

Soft robots were developed by building on the foundations laid by microfluidics research, these systems are often made with soft materials and can be actuated pneumatically or hydraulically, without electronics, making these systems inherently compliant (mechanically and chemically).

In this research sub-topic, we aim to increase the capability of new soft systems (robotic and biochemical) moving from a one-to-one control-actuator architecture and implementing electronics-free control control systems. We have previously developed robots that demonstrate locomotion and gripping using only three-pneumatic lines: a vacuum power line, a control input, and a clock line. We follow the design principles of electronics and have demonstrated integrated fluidic circuits with fluidic switches and actuators. Now that we have realised the basic building blocks of logical operation into combinational logic and memory using our fluidic switches to create fluidic automata and state machines we are exploring how to scale these systems down (to achieve higher density), and up to achieve higher throughput.

These systems constantly push the state of the art by increasing the complexity of soft systems with integrated control. In more recent work we’ve been exploring how to embed control in the characteristics of recirculating fluid flow, and we’re exploring how to come full circle with taking what we’ve learnt from soft robotics and embedding it back into the world of microfluidics for biochemical analysis and synthesis.

Mammalian Tissue Support Systems

Recently we’ve become interested in the opportunities for scientific research and engineering in commercial spaceflight. We have been engaging with government agencies and private companies in the Europe and the USA to explore systems that enable biomedical research in space. We’re exploring how to build systems that enable cold-chain support for precious mammalian tissues, as well as how to enable precision and personalised medical research on earth.

Previously we worked on 3D Soft Lithography and Manufacturing of Microcirculation Phantoms: Microcirculation networks consist of vessels <100µm in diameter; arterioles, capillaries (where oxygen exchange takes place) and venules. Angiogenesis is a common feature of almost all diseases involving the proliferation of new blood vessels at the level of microcirculation. There is considerable interest in understanding the role of microcirculation in terms of hemodynamics and in the development of techniques to measure perfusion. ‘Phantoms’ mimic the geometry and physical properties of the tissues, allowing comparison of properties measured using imaging with known properties in the phantom. We have developed a method for the manufacturing of a microcirculation phantom that may be used to investigate hemodynamics using optics based methods. We make an Acrylonitrile Butadiene Styrene (ABS) negative mold, manufactured in a Fused Deposition Modelling (FDM) printer, embed it in Polydimethysilioxane (PDMS) and dissolve it from within using acetone. We have successfully made an enlarged three-dimensional (3D) network of microcirculation, and tested it using red blood cell (RBC) analogues. We’re now exploring the use of this phantom for testing medical imaging technologies.

Neuroprosthetics and Soft Systems for Surgery

Stretchable and Flexible Electronic Systems: As the electronics industry develops, the demand for stretchable and flexible electronic devices is increasing.
Printed circuit boards are evolving into new flexible, and stretchable electronic systems. This technology promises to expand the design space for engineers and will allow them to create unique, multifunctional, multidomain structures and highly integrated devices.
Our research into fabricating packaging for integrated circuits using soft encapsulation with polymeric material and eutectic liquid alloy allows us to design flexible, and stretchable electronics systems. These systems are mechanically compliant and biocompatible; the technology is applicable to many applications, including: wearable wireless health monitors; spatiotemporal cardiac measurements; environmental monitoring; soft robotics, and smart contact-lenses.
We proposed a rapid and reliable way of making soft-lithography moulds using a laser micromaching system and a self-adhesive material. We presented a poster on this subject at the 2016 MicroTech conference.