IPSc derived human cardiac cells grown on silk disc. 14/10/2016
In November 2015 I was successful in my application for a research grant from The Australia Council for the Arts to work on a project I had been thinking about for many years.
Over the course of the last 15years, my work has been primarily about building analogue automatons, essentially robots that do not rely on digital computers nor microcontrollers to undertake crude but creative tasks. After collaborating with a fantastic team of engineers, scientists and artists for the cellF project in 2014, I had a greater understanding of laboratory protocols and tissue engineering. This gave me a better grounding to make the leap from electronic based actuation to biological – together with SymbioticA and AusCo I started working on Movement and Interface – Possibilities of interfacing human heart cells to artistic robotic bodies.
After weeks of basic lab training, inductions and ethics approval I was able to start initial experiments. Under the guidance of Guy Ben Ary and SymbioticA I was able to purchase materials and seed my first human cardiac(heart) cells.
In order to get moving quickly we chose to start with progenitor cells as they would give results quicker and we could learn the basics. The downside being that these cells are extremely expensive and are unable to be frozen – so once the vial is used more is needed to be purchased.
Due to many factors, the Progenitor cells were not viable and greater understanding of the process of differentiation was needed, to get better efficiency with twitching muscles. Luckily there has been some scientific focus on cardiovascular disease and recently companies have been releasing products to help with laboratory experiments in this field. Surprisingly I was able to buy online Human IP StemCells and a Cardiomyocyte Differentiation Kit
The most amazing thing is that after just 2weeks of working with these new cells I had successfully cultured spontaneously twitching human heart cells in a dish!!!
Furthermore as the cells matured and my lab technique developed I was able to manipulate the way these muscle actuators could move. At such an early stage I was pleased to see that with creative use of scientific processes I could get quite diverse movement potentials.
I had a clearer vision for producing a self propelled bio-engineered structural artwork due to these very early experiments. Here you can see a freefloating mass of attached cells twitching WITHOUT the use of a microscope – with the naked eye – also foreign materials introduced and flexed by the twitching cells… Huzzah!
6months into these investigations I was able to consistently culture twitching cells and improve efficiency. Also my knowledge of lab protocols as well as use of equipment had increased in order to document my work more effectively.
The idea of this artwork is to engineer a self-propelled autonomous biological sculpture and my primary plan was to grow human heart cells on a scaffold of some kind. I experimented using decellularising cellulose materials such as fruit and wood, coral and sea sponge as a substrate on which to attach these twitching cells… We settled on exploring the possibilities of silk as a basis to build the robot bodies.
I was very fortunate to have the assistance of Rodney Dilley who has extensive experience with tissue engineering as well as working with silk devices. Together we devised a process to print silk structures with the light beam of a motorized microscope. Our first experiments were quite crude and rigid but they were able to confirm that the cardiomyocytes would indeed be able to attach to the silk, very exciting advancements.
The process of printing silk with light on a motorized microscope is unique, I have not been able to find reference of it being done before, it has the ability to produce very detailed structures at the macro scale and is repetitive thus ideal for scientific analysis and experimentation. With guidance from Guy Ben Ary on how to use the equipment I developed a virtual model of my scaffold shape in the microscope software. Essentially we are ‘hacking’ a feature that is used to take pictures of petri dish cultures and re purposing it to make pixels of light in a model of what will eventually become an intricate silk design.
Virtual model of silk scaffold
The innovative printing process we developed uses aqueous silk, generously supplied by Ben Allardyce at Deakin University, that is treated with a photosensitive compound inducing hardening when exposed to light, thus the tiny light beam from the microscope is momentarily shone onto the silk in the pattern I have designed on screen, then what results is a silk structure ready for seeding with twitching cells. Genius!
Actual model of a printed silk scaffold
Here is a boring movie of the process, for my own archiving purposes really.
It is important to get these structures as thin as possible, so as to facilitate their bending by the heart cells. I tried many things to make them microns thick, even to the point of designing a custom 3Dprinted positioning device that is fully adjustable on the Zaxis to have more control over the end result.
Much more experimentation is required for developing shapes that both align with efficiently creating movement of the flexing structures as well as assisting with the (as yet undecided) over arching narrative of the artwork itself.
Of primary importance is making the movement visible to the naked eye so currently we are exploring potential processes of self-assembly and trying to optimize the torque strength of the contracting cardiomyocytes.
Below is a movie documenting some of the tests we have done with the human heart cells, flexing and moving different materials. Flexing of foreign fibers, microbeads and PDMS discs can be seen. Towards the end of the clip – Printed silk structures manipulated by live human heart muscles. the printed silk material is easy to make out by its repetitive hexagonal-type construction – this is actually the shape of the aperture of the microscopic light beam.
Prototypes of biobots made from human heart cells and printed silk:
Work is ongoing on this project with the date for completion around late 2018 to mid 2019. Optimization of cell/silk attachment is the priority however there is always room for more twitching efficiency even though I am already extremely happy with the dynamic action of these little actuators!
nathanjohnthompson 