Basic optical sensor for monitoring leukocyte properties in suspension

摘要

The aim of this work is to propose and evaluate a suitable sensor to determine the leukocyte density in suspension. This sensor could be used to development of a home device that allows having relevant medical information on the leukocytes of an individual. To this end, we investigate a simple optical device to measure the average extinction coefficient of leukocytes in suspension. This is equivalent to the measurement of the so-called optical density of cell's suspensions, extensively used in microbiology laboratories. The device utilizes a LED to illuminate a large volume of the sample and a simple lens to collect the coherently scattered light into a photodetector. The resulting transmittance signal has a high signal-to-noise ratio and follows Beer Lambert's law, thus, allowing a straightforward measure of leukocytes average optical properties in suspension or number-density. Compared to the standard way of measuring the optical density of cells suspensions, the proposed device is much simpler and robust. Measurements are insensitive to settling of cells during measurements. The proposed device could be the basis for designing a 'point-of-care' device to follow up progress of leukemia patients at home.