Introduction

• An average adult has 5 L of blood• Blood– Red blood cells– White blood cells– Platelets– Plasma

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Erythrocytes

• Red blood cells• Disc-like bi-concave

shape• O2 and CO2 delivery

• Hemoglobin

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Hemoglobin

• Quaternary protein structure containing heme groups

• 1 RBC = 270 million Hb molecules

• 1 Hb molecule = 4 heme groups

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Heme Group

• Relaxed state– Fe ion becomes accessible

to O2 as it is on the same plane

• Tensed state– Fe ion becomes less

accessible to O2 as it is pulled out of the plane

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

T vs. R state

• Conformational change• Gas pressure driven• Rotational of 15 degrees

Low O2 environment

High O2 environment

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Perceived Clinical Problem

• Shortage of blood supply• Blood types are a barrier to blood transfusion• 4.9 million patients/year needs blood

transfusion in the US• Demand for blood > blood donations

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Respirocytes• 1st nanomedical device-design

technical paper: 1996 by Freitas

• Resembles RBCs• Spherical w/ various diameter• Aid medical treatments:– Anemia– Carbon monoxide poisoning– Respiratory diseases– Blood transfusion

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Respirocytes – Current Design• Powered by glucose

engines• Gas exchange is

selective -- via sorting rotors

• Made of sapphire or diamond (insulators)

• Various diameters from 0.2 to 100 microns

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Respirocytes – Design Issues

• Over-heating• Radiation damage• Interference with other blood components• Biocompatibility• Introduces unnecessary cell aggregation• Over-pressure of gases• Unpredictable robot life time

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Respirocytes – Alternative Design

• Utilize blood glucose as energy source• Flat disc, mimics RBCs – Diameter: 5 μm– Thickness: 1 μm

• Central CPU• Gas selective membrane (diffusion entrance)• Sensor controlled valves• Open/close valves for diffusion• Selective rotors for releasing gas molecules

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Respirocytes – Alternative Design

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Respirocytes – Alternative Design

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Alternative Design – Flow Chart

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Ethical Issues

• Misuse of respirocytes for athletic purposes• Alters the natural body state by introducing

foreign objects• Can create miniature bombs to kill bacteria –

Can create weapons of mass destruction

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

Conclusion and Future Work

• Goal: universal blood source• Purpose: To improve the quality of life of

patients suffering from anemia, lung cancer, blood transfusions, and diseases that cause excess blood loss

• Problems associated w/cell aggregation & biocompatibility requires further investigation

Introduction Respirocytes Ethical Issues Erythrocytes Proposed Design Conclusion & Future Work

References• [1] Lin, S., “Medical Nanorobot: Constructing Biological

Motor Powered Nanomechanical Devices,” Science in NanoMedicine & NanoMechanics.

• [2] “Nanotechnology, nanomedicine and nanosurgery,” International Journal of Surgery, 2005.

• [3] Breault, K. et al., “Nanomedicine,” California Engineer, vol. 82, pp. 9-14, spring 2004.

• [4] http://dev.nsta.org/evwebs/10955/page2.html • [5] El-Sayed, S. et al., “Nanobiotechnology and its

applications.”• [6]

http://www.nda.ox.ac.uk/wfsa/html/u10/u1003_01.htm