Project Lead(s): Lu Chen
Measuring CD4 T-cell counts in HIV patients is an essential part of monitoring disease progression and treatment efficacy but this service is unavailable in most resource-limited countries, leading to spread of the contagious disease and many deaths.
Conventional flow cytometry remains largely inaccessible for routine clinical use at the primary care level, due to its size and cost.
There is a clear and urgent need for a simpler, more compact, cost-effective and portable system with comparable clinical performance.
The project was aimed at developing a hand-held, low-cost, rugged, reliable point-of-care HIV monitoring device to measure CD4 T-cell counts.
They used a novel optical method for particle detection and analysis that forms the basis of a hand-held cytometer.
The method entails capillary microfluidic devices, optical systems and a unique image acquisition and analysis algorithm.
By using a unique, wide-field dynamic imaging technique, the system eliminates all moving components in a conventional multi-colour fluorescence detection system.
The novel detection system enables multi-colour fluorescence detection in one step, without any moving mechanical components.
The prototype system only requires low power and off-the-shelf components.
In order to demonstrate this cell analysis platform, CD4 T-cell counting was chosen as the initial test, in direct comparison with clinical flow cytometry.
Immuno-Trol Control Cells, commonly used stabilized blood samples, were used at two concentrations.
A clinically validated commercial CD4 antibody with dye was used in testing these stabilized blood samples.
Testing produced an average count of 620 ± 15 cells/μL and 184 ± 17 cells/μL for high and low concentrations, whereas the flow cytometer measured 670 ± 70 cells/μL and 158 ± 28 cells/μL respectively.
To demonstrate the multiplexing capability of this cell analysis platform, CD3 and CD4 cells labelled with different fluorophores were detected simultaneously, using a fluorescence filter with two sub-regions.
Compared with other reported particle/cell detection systems, this approach further eliminates any additional moving components, such as mirrors for laser scanning or motion stages for CCD sensor positioning in order to measure a sizable volume of sample.
The imaging approach, combined with use of purposely designed microfluidic chips, creates a unique opportunity for miniaturization of an optical particle detection system.
The project was scaled through Grand Challenges Canada and ChipCare was able to attract $700,000 from social angel investors, resulting in a $2.3 million round of financing – one of the largest angel-related investment deals in Canadian history.