Extracorporeal Blood Therapeutic Devices for Renal Replacement: A Review of Current Technologies and Future Directions Toward Microscale-based Devices

Extracorporeal blood therapeutic devices (ETDs) are medical devices capable of performing treatments outside of the body through an extracorporeal circuit. These devices are widely used in both clinical/hospital settings and at-home care. A prototypical example is the treatment of nephrological diseases through hemodialysis and continuous renal replacement therapy using a hemodialyzer or an artificial kidney. The various applications of ETDs share common limitations such as coagulation, hemolysis, air embolism, and sensitivity reactions, all of which arise from the interactions of human physiology with the treatment mechanisms. Researchers are implementing microscale-based technology to achieve the next-generation ETD that can address persistent problems and improve therapeutic performance. This review article focuses on the evolution of the structure and development of conventional ETDs towards the miniaturization of the device. We begin with a narrow but common definition of ETDs as well as their current form and uses for renal replacement followed by a review of the importance and progression of microscale-based ETD development together with future directions towards achieving fully functional micro-scale-based ETDs that reflects contemporary technological and engineering advancements.