Lab on a Chip Blog

Scientists in Canada have developed a method to study the changes in red blood cells caused by the most common malaria parasite Plasmodium falciparum.

The malaria parasite is spread by mosquitos. © Shutterstock

Malaria causes approximately one million deaths each year and there is a lot of research surrounding the disease’s biomechanics, aimed at diagnosing patients and developing treatments. The parasite, spread by mosquitoes, infects red blood cells and reduces their ability to deform. Measuring the deformability of an infected red blood cell can provide vital information about the disease’s mechanism and response to treatment.

Current methods to measure deformability are complicated or not sensitive enough, but Hongshen Ma at the University of British Columbia, Vancouver, and colleagues, have designed an accurate and simple microfluidic device for this purpose. The device consists of two layers that control the cells so that only a single cell is introduced into a funnel containing a series of different sized constrictions. The pressure required to push the cell through a constriction is measured precisely and used to calculate the deformability.

The team used their device to show that the deformability of uninfected red blood cells can be distinguished from cells at various stages of infection.

Abhishek Jain at Boston University, US, is an expert in biomedical devices and comments that ‘the device is elegant in the sense that it can be easily scaled up for diagnosis and high throughput drug testing for not only malaria but other pathologies like sickle cell anaemia’.

‘We hope our technique will provide a useful biomechanical assay for the development of new drugs,’ says Ma, who adds that ‘the ability to easily measure the deformability of red blood cells will help researchers study the mechanism of the disease and investigate complex challenges, such as drug resistance.’

Ma’s team plans to further test their device and use it to study the mechanisms of drug resistance.

Microfluidic biomechanical assay for red blood cells parasitized by Plasmodium falciparum
Quan Guo , Sarah J. Reiling , Petra Rohrbach and Hongshen Ma
Lab Chip, 2012, Advance Article
DOI: 10.1039/C2LC20857A

Original article published at Chemistry World

A vertical microfluidic probe developed by researchers in Switzerland can create a range of immunohistochemistry staining conditions on a single tissue sample.

Immunohistochemistry is a process of detecting antibody biomarkers and is regularly used to reveal abnormal cells in tissue sections. Pathologists conducting immunohistochemistry tests often work with very limited samples for which they don’t know the optimal staining conditions. Under-staining can give a false negative, but over-staining causes loss of contrast and can generate false positives.

The diamond-shaped probe is positioned above the tissue sample and scans horizontally across it. The microchannels inject and aspirate liquids at a distance of 1-30µm from the tissue section

Now, a microfluidic device developed by Emmanuel Delamarche and colleagues at the IBM Zurich Research Laboratory, Rüschlikon, offers local staining of tissue sections, which allows a range of staining conditions to be used on one section. The microfluidic probe is positioned vertically above the tissue section and scans horizontally across it. The head of the probe has two apertures at its apex. The liquid is injected onto the tissue section from one aperture and aspirated at the second. ‘Instead of incubating the entire tissue section, the probe can scan it with a variable speed so as to vary locally the incubation time. This is a simple trick, but it should give an optimal staining contrast at least on one spot of the sample,’ explains Delamarche. Tissue sections are prepared for staining in the conventional fashion and post-staining processing is also unchanged.

Delamarche and the team have shown proof of concept with their current research, but in the future, they hope it will receive clinical validation. In addition, the probe could be used for fundamental research. ‘Developing a novel tissue staining method to detect various biomarkers is critical to obtain a more accurate and sophisticated understanding of drug discovery and clinical pathology,’ explains Je-Kyun Park, an expert in bioengineering at the Korea Advanced Institute of Science and Technology, South Korea. Using the microfluidic probe to scan multiple locations with different conditions could help analyse tissue microarrays.

Micro-immunohistochemistry using a microfluidic probe
Robert D. Lovchik, Govind V. Kaigala, Marios Georgiadis and Emmanuel Delamarche
Lab Chip, 2012, Advance Article
DOI: 10.1039/C2LC21016A

Original article published at Chemistry World