Hyperspectral fluorescence Imaging: the potential of cryogenic detectors

David Ray

Chief Technology Officer BioAstral Limited

What does BioAstral have to offer the stem cell research community?

We have taken detector technology developed by ESA for X-ray astronomy and deployed it down the microscope to image fluorescence from bioassay

This capability is based on superconducting tunnelling junction (STJ) devices

Initial results using specialised kit at ESTEC, based on single pixel tantalum detectors, took us

by surprise

Photon detection across the visible spectrum from UV to IR

Two to three orders of magnitude improved sensitivity over conventional PMT or CCD detectors

Essentially no background noise

We measure the energy of photons directly, without the need to infer colour by use of filters

This adds up to the potential for sensitive and true hyperspectral imaging across the optical spectrum and into

the infra red

This might have been a curiosity restricted to specialist cryogenic labs

But for the quite independent development of commercially available user-friendly cryogen-free coolers capable of

operating at extended periods at milliKelvin temperatures

Here we had the potential to take STJ detectors and operate them in a biology lab

And this has been the focus of BioAstral efforts to date: to take STJs and get them to operate routinely in the new coolers

Scanner Process

Excitation

FluorescentBiomedical

Sample

CoolerSTJ

Light capture

Data acquisition

Data analysis

1

2

3

Instrument control

4

We still have some technical problems to resolve before our STJs work as well in the Heliox cooler as they do in

ESA’s helium dilution refrigerators

But we have identified solutions to these problems and we have the resources in place to implement these

Our next step will be to refine the benefits of HPD for live cell research

The ability to look at two, three perhaps more colours simultaneously without problems of photo-bleaching

The use of lower excitation energies

The use of fluors better suited to maintaining cell viability

Possibly even the use of auto-fluorescence to selectively characterise cell biomarkers

True multicolour photon imaging

Potentially transformative in terms of biology and life sciences research

Enabling diagnostics for personalised medicine

Disruptive of current markets