Group leader: 

Pierre O Bagnaninchi

Position: 

Associate Researcher

Contact: 

pierre [dot] bagnaninchi [at] ed [dot] ac [dot] uk

Aims
Our main research interest is the development of new monitoring technologies for tissue engineering and regenerative medicine based on optical coherence tomography and dielectric spectroscopy. Our specific aims are to provide new technologies to monitor differentiating stem cells in real time and without making use of labelling agent, and to continuously image cellular events in three dimensional matrices.

Background
At present stem cell populations in living cultures can only be identified from their differentiated progeny by cellular morphology or by expression of fluorescent proteins (usually expressed by genetic engineering) in FACS-based or real time microscopy.  Alternatively, immunofluorescent labelling of specific membrane proteins and gene-expression analysis allow analysis of differentiation, but these techniques (Immunostaining, Flow cytometry, qPCR) require the cells to be lysed, fixed and/or labelled. They are therefore ‘snap shot’ measurements of cellular differentiation unsuitable for real time analyses that would greatly increase the power of high throughput and high content analyses. The challenges posed by analysing stem cell behaviour in living cultures are made much greater by the commonly used techniques of formation of 3D cellular aggregates to grow stem cell populations.  So, for example, when cells are not dissociated and analysed after fixation and/or lysis, the analysis of human embryonic stem cell differentiation in a 3D environment (Embryoid body) can be challenging. These challenges are even greater when, as will be necessary for the majority of therapeutic applications, stem cells are loaded in a 3D carrier, or scaffold, to conduct tissue regeneration. Assessing 3D culture homogeneity/heterogeneity non-destructively will be essential to pre-clinical quality control.  

Ultimately, an imaging modality that does not employ the expression of fluorescent proteins or other labels will prevent cellular toxicity in long term analyses required for living cultures, and could enable quality assessment for cell replacement therapies. Therefore, being able to monitor stem cell differentiation at a single-cell level in time and space without labelling, will be complementary to the existing techniques, and a major advance in the stem cell field facilitating both the growth of cell populations for regenerative use and also the development of automated assays suitable for drug discovery and toxicity studies.

Approaches and progress
We are currently developing an optical coherence phase microscope that will be used in combination with dielectric spectroscopy to record cell lineage specific signature in 3D.

Funding
RCUK Fellowship
EPSRC