University of Washington (UW) scientists and engineers are working on a low-cost device that will help pathologists diagnose pancreatic cancer faster. The first-generation device is extremely simple. It uses a fluidic transport system to expose a needle biopsy tissue sample to the sequential steps involved in fixing and staining samples for diagnosis. We spoke with Ronnie Das, a UW researcher in bioengineering and lead author of the published paper (1).
How did you get started? The inspiration came from a related project to image tissue biopsies in 3D to aid in cancer detection and diagnosis. Pancreatic cancer development is not fully understood, and we think 3D visualization of whole tissue may provide (for a lack of better words) an added dimension to detection and diagnosis. However, before biopsies can be imaged and evaluated by a pathologist, they must be processed. This can take days. Since we were dealing with small tissue and fluid volumes, we thought “why not use microfluidics?” This resulted in our instrument: a disposable, silicone-based, credit card-sized device consisting of several circular cross-section microfluidic channels that can replicate the rudimentary processes of a pathology laboratory in minutes (see Figure 1). Our device may provide a route for human-free handling, and since we are processing whole tissue for 3D imaging, the device also preserves specimens so that traditional pathology may still be performed. This could help maximize the information from patient biopsies while causing minimal disruption to the pathologist’s workflow.
Any surprises? This whole project continues to surprise us on both a scientific and engineering level! Microfluidics R&D is everywhere, so it surprised us that no one (to the best of our knowledge) employed microfluidics to transport and/or process whole intact tissue directly obtained from a patient. The sheer novelty and simplicity of the idea, along with the ease of creating and implementing it, means it has been well-received by the scientific community, and we have recently been awarded a National Institutes of Health exploratory grant to continue our work.
What were the challenges? An ongoing challenge is effective tissue staining. The last significant study on whole tissue staining and processing was performed in the 1960s, when 3D optical imaging was not yet invented, so in some ways, we are rediscovering the art of staining. Specific and controlled diffusion and absorption of stains in slices is quite different from whole tissue cores that are 50–5,000 times larger in volume. Ultimately, we are servicing medical doctors, pathologists and clinical professionals, who make the hard calls. The challenge is simple: our device must be able to reproduce exactly what pathologists are used to seeing on a daily basis, by matching or emulating traditional processes that have been established for nearly half a century.
What impact could the device have? Processing biopsies takes time, and a pancreatic cancer diagnosis can be terrible for patients. We hope our device could eventually help reduce patient wait times, inconvenience and cost in delayed decision-making. Combined with our imaging system, and collaboration with Melissa Upton, professor of pathology at UW, we hope the tissue staining ability of the device could lead to highly informative 3D visualizations of biopsies to aid in early detection of cancer. Other applications could include processing biopsies outside of cancer, and combination with other clinical technologies, such as ultrasound elastography.
What’s next? Our main aim is to characterize and optimize our device and its functions to pathology standards. We are attempting to flow tissue from the device to the 3D imaging platform. Future designs under consideration will incorporate onboard optics or even include an interface for smartphone cameras to collect imaging data.
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References
- R. Das et al., “Pathology in a Tube: Step 1. Fixing, Staining, and Transporting Pancreatic Core Biopsies in a Microfluidic Device for 3D Imaging”, Proc. SPIE 8976, Microfluidics, BioMEMS, and Medical Microsystems XII, 89760R (2014).
