MDR Vacation Bursary Project: Engineering mechanically-defined microenvironments for stem cells
by Luke Goater
By Pernille Fladsrud, undergraduate student, Faculty of Engineering and the Environment
I just completed my third year in Mechanical Engineering at The University of Southampton, and will continue into my last year of a four-year Master of Science (MSc) degree after summer. My degree theme is engineering management, but I have also chosen to focus on bioengineering. This internship project is in collaboration with Dr Nick Evans, in the Centre for Human Development, Stem Cells and Regeneration and the Bioengineering Sciences Group. The field of research for this project is stem cells and wound healing, and how mechanical signals affect cell behaviour and wound healing.
Human adult skin is a heterogeneous tissue, and we’ve been attempting to model its mechanics in vitro. During my third year individual project I worked with Dr. Evans to design an apparatus to fabricate polyacrylamide hydrogel substrates with varying stiffness; i.e. surfaces whose stiffness varied as a function of distance in the x and y directions. We’ve been doing this to find out how stiffness variations affect the way skin cells differentiate, migrate and proliferate over a heterogeneous surface – a particularly important consideration during wound closure. The stiffness variation in the hydrogels was tested applying the method of Atomic Force Microscopy, and force maps were plotted of the various stiffness regions. (Figure 1)
Figure 1: Force maps of the low stiffness and high stiffness region in one single polyacrylamide hydrogel
We found that keratinocyte skin cells migrate to the areas of higher stiffness, which we predicted before the experiments. This can be seen in (Figure 2), where the cells have migrated to higher stiffness stripes in a striped patterned substrate. This Vacation Bursary project has given me the opportunity to further investigate the field of wound healing, and continue my interest within bioengineering.
Figure 2: Patterned hydrogel substrates, after 24 hours of cell culture with keratinocyte skin cells. Cells have preferentially migrated to areas of high stiffness.
At the moment we are investigating how topography alone, or topography in combination with varying stiffness, affects the behaviour of cells. The epithelium of the skin has an undulating topography, and we’re trying to model this by 3D printing various moulds with ‘doubly sinusoidal’ topographies – i.e. two crossing sinusoidal waves in a pattern with various wavelengths and amplitudes (Figure 3). We are collaborating with Shoufeng Yang in the Engineering Sciences Unit to achieve this. We are then seeding cells onto polyacrylamide hydrogels made from these moulds, and we will investigate how the “steepness” of the topography affects the skin cells.
Figure 3: Polyacrylamide gel substrate made in 3D printed mould
In my final master year after summer I will participate in a group design project with six other students, which aims to design a bioreactor. The Vacation Bursary project will help me develop my understanding regarding mechanical forces and signals connected to cell growth and development, which will be very beneficial in my further studies within bioengineering.
MDR Vacation Bursary blog series available at: http://blog.soton.ac.uk/multidisciplinary/tag/vacation-bursary/
Latest Insights: Digital technology, learner identities and school-to-work transition project
by Alison Simmance via Work Thought Blog
Latest Insights into the Digital technology, learner identities and school-to-work transition project by Michaela Brockmann. We are an interdisciplinary working group at the Work Futures Research Centre at Southampton University. Funded through SIRDF (Strategic Interdisciplinary Research Development Fund), our aim is to explore the role of digital technology in the formation of learner identities […]
MDR Vacation Bursary Project: Particle manipulation in liquid using ultrasonic methods
by Noorvir Aulakh
By Noorvir Singh Aulakh, undergraduate student, Faculty of Engineering and the Environment
Cell sedimentation in micro-cannulae posses a fundamental impediment in homogenous cell-delivery, during neurosurgical operations. The procedure requires the injection of neural stem-cells, directly into the patient’s brain. The injection procedure is realised through one of two methods. The former method involves the cell-containing cannula, oriented perpendicularly to the ground (the vertical configuration), while the latter bears the cannula parallel to the ground (the horizontal configuration). Sedimentation results in vastly inhomogeneous cell distribution across different injections from the same cannula. The aim of this project is to minimise this phenomenon using acoustic forces to levitate cells, in the suspension medium. To conduct the initial experimentation, I will be employing florescent micro-beads, suspended inside a capillary.
With the use of acoustic techniques, it possible to set up ultrasonic standing waves in the capillary. A PZT transducer attached to the capillary converts an electric signal input to a mechanical output. By modulating the experiment variables (frequency, amplitude etc. of the input signal), the particle suspension can be manipulated. Ideally, the cells would be forced into the mid-plane of the capillary, away from the walls.
There are, however, fundamental stipulations considering the design of the device. Proximity to brain tissue limits the size of the cannula, as well as strength of the ultrasonic forces. Furthermore, acoustic levitation of particles in stagnant flow conditions still remains a relatively unexplored topic.
I will be working under the supervision of Professor Martyn Hill, Dr. Dyan Ankrett along with, Dr. Dario Carugo. This project was conceived through the University Hospital of Wales, Cardiff, where the neurosurgeons observed this cell-sedimentation predicament. It has therefore come to the attention of Southampton University Engineering Department, and successful results can be directly applied to today’s medical industry.
So what do the digichamps actually do?
by Lisa Harris via Digital Economy USRG
With many thanks to the film-making wizardry of Simon Morice, the interviewing skills of Flo Broderick and contributions from Gareth Beeston, Renaldo Bernard and Eamonn Walls…this is what the #digichamps do 🙂 See more on the Digichamps blog. It’s been a busy week for the digichamps. Here are Simon Morice and Flo Broderick preparing video […]
Mapping Libel Performance in Early Modern Devon: Results
by Clare Egan via Digital Humanities | Digital Humanities
The pilot resource mapping a sample of the performance-based libel cases from early-modern Devon is now complete. Its layers include the locations used for performance in all ten libel cases with attribute tables associated giving information about each case – these are plotted on a modern map of Devon showing geographical features such as county boundaries, elevation and rivers. The …
Using social media to present about social media…
by Lisa Harris via Digital Economy USRG
Making the most of social media preso with @graemeearl & @flobroderick to @multisoton #digichamps #sotonde http://t.co/eazPa40zoh — Lisa Harris (@lisaharris) July 4, 2013 As @lisaharris @GraemeEarl @FloBroderick are speaking about social media, I thought I should tweet about it! http://t.co/09vUbzg9xz #usrg — Rikki Prince (@rikkiprince) July 4, 2013 @GraemeEarl is live at the USRG Chairs […]
Mapping 17th century libel performance: a geodatabase of Early Modern Devon
by Philip Riris via Digital Humanities | Digital Humanities
This brief post aims to communicate and evaluate the outcomes of my participation on Clare Egan’s project within the sotonDH framework. I will characterize the spatial data produced as a result, as well as offer a reflective account of my experiences collaborating with another researcher in a different Humanities discipline. Clare has previously detailed the raison d’etre of the project …
Precarious work futures?
by Catherine Pope via Work Thought Blog
Amongst all the fuss about the recent Great British Class Survey (GBCS), a collaboration between social scientists Professor Mike Savage and Professor Fiona Devine of LSE and University of Manchester, and the BBC was the interesting observation that the group at the bottom of the social class structure are what the survey’s authors call the […]