1. A Microfluidic model for single-cell capillary obstruction by Plasmodium falciparum-infected erythrocytes (Shelby and White et. al) _____________________________________ 20.309 presentation Friday, December 3 rd, Sameer and Nadia

2. Johns et.al. Nature Medicine - 12, 170 - 171 (2006) doi:10.1038/nm0206-170 Malaria up close

3. Marti M et al. J Cell Biol 2005;171:587-592 © 2005 Rockefeller University Press Asexual Development of Malaria parasites in iRBC

4. Plasmodia in Action!

5. Why is this assay useful? Limitations of current in-vitro techniques (Lack of animal models- mimic capillary milieu) Technique is simple, inexpensive and efficient Explains high parasitemia in a growing capillary blockage in REAL TIME Provides additional information to micropipette aspiration, viscometers, or single erythrocyte rigidometers (SER)

6. Optical Set up: Differential Interference Contrast (DIC)

7. Schematic illustrating the geometry of the micro- channel. ©2003 by National Academy of Sciences Fabrication of channels using PDMS -Channels fabricated in PDMS -Length ~3-5x W -Depth 2um to prevent cells turning sideways

8. Four stages of malaria-infected RBCs passing through channel constrictions. Shelby J P et al. PNAS 2003;100:14618-14622 ©2003 by National Academy of Sciences

9. Erythrocyte Shape Recovery Early Trophozoite Stage Schizont Stage 40um channel StageRecovery Time Early Trophozoite~ 30s Schizont~ 1-2 min

10. Normal Erythrocytes passing through blockages Shelby J P et al. PNAS 2003;100:14618-14622 ©2003 by National Academy of Sciences 60um channel Infected cells block passage above/below Cell weaves through blockage Cell exits blockage

11. Conclusions and Future Applications Technique is simple, inexpensive and efficient for studying infected erythrocytes Adjusting mechanical properties could help study flexibility and cytoadherence of iRBCs – Interactions with other RBCs, cell-surface receptors, endothelial cells Can be used to screen potential drugs that target mechanical behavior of iRBCs

12. Extra Slides

14. Pitting of Infected RBCs. Shelby J P et al. PNAS 2003;100:14618-14622 ©2003 by National Academy of Sciences