Friday, May 25, 2012

POC Diagnostics - A walk in the PARC

Hey everyone.. I’m back..!

It’s not as if stuff hasn’t been happening around here. Dusty blogs = all work less play. Yesterday I attended a very inspiring talk and I decided today I just have to take an hour off and summarize it here! 

It was Peter Keisel from the Palo Alto Research Center. PARC is an independent subsidiary of Xerox, and consists of about 170 researchers in 4 labs. This work on sophisticated point-of-care opto-fluidic detection from their opto-electronics group was super-exciting! I had been looking forward to meeting Peter Keisel and hearing more about his work. Finally everything came together at the N-Cal OSA meeting yesterday.
Diagnostics and testing of water, blood, and other samples often involves counting cells or particles of a certain type, defined by size, spectra or other characteristics. Equipment like flow cytometers are often used for such testing. But their size, cost and complexity limits their availability. Therefore, such testing is often conducted in dedicated labs and testing centers. Depending on the local infrastructure and perishable nature of the test sample, this costly and time consuming effort, sometimes may not even be possible. Hence development of compact, inexpensive and robust devices for point-of-care testing is a critical and active area of research. 

Peter discussed an opto-fluidic detection device developed by his team at PARC. The device contains...
.. a channel with flowing particles, illuminated with an extended excitation light source (LEDs and lasers, both work). The signal from the moving particles is modulated by a spatial mask as they flow and pass by different portions of the mask. At a given time, signal from all the particles, flowing at a known speed, along the known mask, is integrated on a photodetector (or APD or PMT if you need more signal). The time dependent signal is then processed with correlation and FFT analysis to detect and count the number of particles that emitted this modulated signal. This device is small, requires no complicated laser sources or optics,therefore has very little alignment and cost. 

Handheld prototype at PARC
The size of the smallest particle counted is determined by the feature size on this spatially modulated mask. You can design different masks for different sized cells, and use colored patterned masks for identifying different spectra. They showed pictures of a handheld prototype (shown above). The light source, optics and detector are fixed. The channel itself can be made into a detachable use-and-throw chip which can be varied with different masks for different diseases or particles. He showed good results for detecting HIV (CD4 testing), water monitoring for giardia, cryptosporidium, e-coli and other pathogens. 

Considering that PARC is a largely research organization and does not sell medical devices, it was very interesting to hear how the device was invented and what will become of it. Peter mentioned that their research on this spatial modulation technique started out several years ago with quite different applications in mind. Over time they evaluated areas which could derive greater benefit and, about 2 years ago, they zeroed in on developing this compact and low cost device for point-of-care diagnostics. It currently costs less than 350$ and they are working on further miniaturization and looking for partners to collaborate and commercialize this device. 

Our sincere thanks to Peter Keisel for telling us all about this research and the evolution of this device. A flexible and portable device like this would be a life-saver in remote locations, allowing doctors and nurses to deliver critical disease diagnosis and remedies, decide if the water in this well or stream is contaminated, and whether this fever will go away in a week or 7 days.

Thanks for stopping by, folks! Cheerio!

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