Cell analysis in a microfluidic cytometer applying a DVD pickup head

In this paper we present an optical detection system for single biological cells that utilizes a standard DVD pickup head. In a feasibility study we have shown the detection for different particles and cells (yeast) suspended on a platinum mirror. For those experiments the integrated magnetic actuator of the pickup was used to simulate the particle movement and we found a remarkable sensitivity. Then a microfluidic flow cell with an integrated mirror was designed to be able to measure particles in a cytometric setup. The mirror at the bottom of the flow channel reflects the focused laser beam back to the integrated photodiodes. The advantage of using a DVD pickup head is not only in the low cost but also in the ability to use the integrated magnetic actuators to adjust for alignment errors between flow channel and pickup. Measurement results are given that show the high sensitivity and good repeatability for polystyrene beads and erythrocytes from cattle. In a two-parameter plot the cytometric separation of a mixture of counting beads and erythrocytes into two sub-populations is demonstrated.