The Stevens group’s substantial experience in designing materials for tissue engineering based on explorations of the cell-material interface is enabling the rational design of biomaterials with extracellular influences introduced in optimised forms. Fundamental cell-material interface mechanisms are explored across the length scales from the cell to the tissue level with state of the art bioengineering and materials science, including the application of live cell Raman spectroscopy for cell fingerprint phenotyping differentiating cells on engineered materials.
• Raman microspectroscopy shows tremendous promise for the analysis of biological processes within living cells, such as cell cycle dynamics, cell differentiation and cell death. Unlike conventional biological assays, laser-based Raman spectroscopy enables rapid and non-invasive biochemical analysis of cells in the absence of fixatives or labels. The low Raman signal of cell culture buffer/media permits the rapid monitoring of living cells growing under standard cell culture conditions. The Raman spectrum of a cell is a biochemical 'fingerprint', containing molecular-level information about all biopolymers contained within the cell. The high information content of Raman spectra can be used to characterize the distribution of multiple cellular components, and to study the dynamics of subcellular reactions, with excellent spatial resolution that is not apparent in traditional PCR and proteomics experiments. The Stevens group applies live cell Raman spectroscopy and multivariate analytical techniques to study cell differentiation/tissue engineering, heart valve calcification and toxicological studies. We recently published in Nature Materials [Gentleman, Swain, Evans, Boorungsiman, Jell, Ball, Shean, Oyen, Porter and Stevens, 2009
] on the use of Raman microscopy and NIR laser light in elucidating stem cell signature ‘fingerprints’ [Swain, Kemp, Goldstraw, Tetley and Stevens, 2010
]. We have also developed cutting-edge microscopies for correlative cell imaging to correlate SEM-like micrographs with fluorescence images, which is advantageous because it correlates topographical and biochemical information with nanoscale resolution [Bertazzo, von Erlach, Goldoni, Çandarlıoğlua and Stevens, 2012
• As recently published in Nature Materials [Bertazzo, Gentleman, Cloyd, Chester, Yacoub and Stevens, 2013
], the Stevens group has used nano-analytical electron microscopy to investigate nanoscopic hydroxyapatite particles during the calcification of human cardiovascular tissues, which has numerous implications in calcification-related cardiovascular diseases. This work has also been featured as the Front Cover
of that issue of Nature Materials, on Materials 360 Online
and in C&EN
(Chemical & Engineering News).
• Another innovative approach used by the Stevens group to investigate mineralisation focused on the role osteoblasts play in mediating bone apatite formation. Nano-analytical electron microscopy was used to investigate samples containing osteoblasts with preserved mineral, ions and extracellular matrix, where calcium-containing vesicles conjoining mitochondria suggested storage and transport mechanisms [Boonrungsiman, Gentleman, Carzaniga, Evans, McComb, Porter and Stevens, 2012