High-Index Optical Materials for High-Throughput Lensfree Imaging, Counting and Sorting of Cells on a Chip

We describe a high-throughput lensfree optical imaging system that can characterize numerous cell types found within a heterogeneous mixture. Here, we specifically discuss the effect of the refractive index of the substrate material on the performance of the proposed lensfree optical cell characterization platform. It is experimentally illustrated that the use of high index materials such as SrTiO₃ significantly improves the signal-to-noise ratio of the acquired lensfree images, which is a significant step towards more robust high-throughput cell analysis and characterization. The imaging configuration of the reported high-index material based characterization scheme is massively parallel enabling a cell counting speed of >100,000 cells/sec over a field of view of ∼10 cm². This novel system can also form the basic building block of a simple and compact point-of-care cell counting technology that can be made as small as a regular cell-phone to rapidly measure the count of e.g., red blood cells or T-lymphocytes from whole blood samples. Such a powerful point-of-care platform may have a significant impact especially for global health related problems in the developing world.