Plastic Pays

Point-of-care (POC) tests developed for use in resource-poor countries are often centered on rapid, user-friendly ways to diagnosis a single disease, such as HIV. But if the causative disease is uncertain, or you need to monitor a patient’s progress, this approach might not always be the best one. Now, a team from Rice University, Texas, USA, have developed an all-plastic, 3D printed, digital fluorescence microscope to allow POC white blood cell (WBC) differential measurement (see Figure 1).

The low-cost microscope allows analysis of lymphocytes, monocytes and granulocytes in whole blood samples stained with acridine orange, which can be applied directly to wet, undiluted blood samples. The device also requires no manual optical adjustment between samples, allowing for preliminary imaging of a sample in just 10 minutes (1).

These factors could be particularly useful in helping healthcare workers better diagnose a range of conditions, such as bacterial or viral disease, or, for example, a change in total WBC count.

Point-of-care (POC) tests developed for use in resource-poor countries are often centered on rapid, user-friendly ways to diagnosis a single disease, such as HIV. But if the causative disease is uncertain, or you need to monitor a patient’s progress, this approach might not always be the best one. Now, a team from Rice University, Texas, USA, have developed an all-plastic, 3D printed, digital fluorescence microscope to allow POC white blood cell (WBC) differential measurement (see Figure 1).

The low-cost microscope allows analysis of lymphocytes, monocytes and granulocytes in whole blood samples stained with acridine orange, which can be applied directly to wet, undiluted blood samples. The device also requires no manual optical adjustment between samples, allowing for preliminary imaging of a sample in just 10 minutes (1).

Other POC systems for analyzing WBCs do exist, but with a purchase cost of over US$1,000, and a per-test cost of over $3, which is unfeasible for many resource-poor regions. Though their prototype cost over $3,000 to create, if mass-produced, the team estimate this could fall to around $600, with each test costing only a few cents. “One of the driving aspects of the project is the cost of the sample or sample preparation. Many systems which work for point-of-care applications have quite expensive cartridges. The goal of this research is to make it possible for those in impoverished areas to be able to get the testing they need at a manageable price point,” says Tomasz Tkaczyk, an associate professor at the Department of Bioengineering, Rice University, and part of the team who developed the microscope.

Future plans for the device include comparing the differential counts obtained with the plastic microscope to results from conventional benchtop WBC analysis. The team also hope to develop an automated algorithm for WBC identification, with the overall aim of making blood work cheaper, faster and easier in settings where expensive lab equipment may not be an option.