Low-cost 3D imaging of small biological samples

Optical Projection TomographyOptical Projection Tomography (OPT) is a form of “mesoscopic” imaging that fills the gap between conventional microscopy and MRI, enabling optical molecular 3-D imaging of small samples without sectioning. Specimens are made transparent in most areas and are suspended in an optically suitable medium; wide-field images are then taken from multiple angles and recalculated as a 3D image by computer software. The technique can utilise fluorescence or absorption of coloured stains, enabling imaging of organs and tissues.

There are currently few low-cost commercially available mesoscopic imaging systems, and so researchers from the Department of Physics, led by Dr James McGinty and Professor Paul French, used BBSRC IAA funding to build on outcomes from a BBSRC Tool and Resources Development Fund grant to develop an open source second generation prototype of a microscope stage-top OPT module that can be implemented on any inverted widefield fluorescence microscope as an add-on component. This module allows 3-D imaging of mm-sized samples, including in vivo imaging of small organisms, such as zebrafish larvae. The team have published a parts list and CAD drawings alongside the open source software, enabling non-commercial researchers to replicate the system at a low cost. The team’s OPT development was previously supported by a Brian Mercer Feasibility Award (now known as the Royal Society Translation Awards), to the value of £30,000, which delivered prototype instruments in use in at Hammersmith Hospital and at the Sir Francis Crick Institute.

The stage-top OPT prototype has been trialled in Imperial’s Facility for Imaging by Light Microscopy (FILM) and could be available for use by researchers across the College. The team are also in discussions regarding the potential for commercialising OPT instrumentation alongside making the design and software openly available to the wider community.