Optical Coherence Tomography Imaging of Tissue Engineered Skin Cultured Under Perfusion Conditions

Tissue engineered (TE) human skin constructs are useful for the investigation of disease pathologies and for exploring the potencies and side effects of medicines and cosmetics. However, TE skin constructs are limited by their short lifespan of 14 days in the laboratory. Perfusion culture methods provide a flow of medium past TE constructs and have been suggested to increase their lifespan by improving the delivery of nutrients. Another challenge with TE skin constructs is our inability to assess their quality during long term culture without performing destructive histology.
The aim was to combine perfusion culture of TE skin constructs with the use of optical coherence tomography (OCT), a non-destructive imaging technique to follow the development of TE skin over time. Commercially available bioreactor chambers were modified in order to combine perfusion culture of TE skin at an air/liquid interface (ALI), which is necessary for skin maturation, with in situ OCT imaging during culture.
OCT imaging was able to non-invasively observe the developing structure of TE skin constructs during culture with minimal preparation. The combination of perfusion culture techniques and OCT imaging produced good quality TE skin and allowed observation of its development over the culture period. The design and development of perfusion culture systems were challenging, particularly with regard to maintaining a stable ALI and sterile conditions.
The current perfusion bioreactors while interesting in concept would require further development to improve ease of use. Further work on OCT analysis should focus on the establishment of robust quantitative measures of quality, for which epithelial thickness will be useful.