Making Connections: Building in vitro models of tissue interfaces using 3D bioprinting technologies

Supervisors: Dr Jennifer Paxton (see also here), Dr Lyndsay Murray

Project Description:

This project in a collaborative and interdisciplinary venture between Dr Paxton, an expert in tissue engineering, and Dr Murray, an expert in molecular analysis of the neuromuscular system.  

There are many regions in the human body where two different tissues join together. For example, in the musculoskeletal system, the soft tissues of tendon and ligament join to the hard tissue of bone though a unique, carefully constructued connecting region, which has an important job in protecting both tissues from damage1,2. As a functional connection, the microanatomy of the bone-tendon/ligament interface (or enthesis) is important to understand since tendon/ligament injury is common in sports. When a tendon/ligament is ruptured, and surgery required to re-attach the soft tissue to bone, the normal tissue connection structure is lost, and unorganised scar tissue is produced, leaving the surgical interface weak and prone to further injury.

This project aims to apply novel techniques in tissue engineering to develop a reproducible co-culture method whereby the cells from two different musculoskeletal tissues (e.g. bone and tendon) can be grown in close apposition. Then, we aim to apply cutting-edge molecular techniques to investigate what happens when cells from ajoining tissues grow together during development and after injury. By doing so, we aim to develop a tool whereby future investigations into treatment options can be explored with the ultimate goal of improving patient outcomes following musculoskeletal injury. To accopmlish this, we will employ the novel technology of extrusion-based 3D bioprinting3, where cells are encaspuslated within a polymer ‘bioink’ and ‘printed’ with high precision in culture plates. The Paxton Lab owns a 3D bioprinter with a duel printhead functionality, which will enable the printing of duel cell types (e.g. bone and tendon cells) in polymers in a variety of different orientations, modelling a 3D interfacial region. Once 3D co-culture constructs have been bioprinted, we will profile the molecular changes occuring when cells interact.  RNA will be extracted from co-cultures at regular time points following co-culture creation, and RNAseq analysis will be used to profile the evolving transcriptome as cells interact. Bioinformatic analysis will then be used to identify key cellular pathways and signalling cascades which mediate the interactions between bone and tendon cells as they form an rudimentary enthesis. This will provide an insight into the developmental pathways to investigate further in the co-culture systems and help to formulate a novel model system to study interfacial development and repair.

The key experimental techniques involved in this project are; 
•    2D/3D cell culture, 
•    3D bioprinting, 
•    histology
•    immunohistochemistry, 
•    RNAseq
•    Bioinformatic analysis of transcriptional data 

Training will also be provided in experimental design, data collection, data analysis and presentation skills.

References:

1.    Benjamin M., McGonagle D. (2009) Entheses: tendon and ligament attachment sites Scand J Med Sci Sports 19(4):520-7
2.    Paxton JZ., Baar K., Grover LM. (2012) Current progress in enthesis repair: strategies for interfacial tissue engineering. Orthopaedic and Muscular system. 2012 S1.
3.    Mandrycky C., Wang Z., Kim K., Kim DH. (2016) 3D bioprinting for engineering complex tissues. Biotechol Adv. 34(4) 422-434 

If you wish to apply for this project, please check this link and send your application to this email.
 

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