Study On Integrated Insulin Delivery System Based On MEMS Technology

The closed-loop controlled insulin delivery sysytem based on MEMS (Micro Electro Mechanical Sysytems) technology is a controlled release micro liquid transport system. It is the application of MEMS in biomedical engineering and is the one of the most interesting researching field in Bio-MEMS. In the insulin delivery system, the mechanical pump and syringe are replaced respectively by piezoelectric micro pump and micro needle array which are both MEMS actuators. The micro needle array and micro pump can be fabricated by IC processes with low cost and high yield. The main research contents and creative points in this paper are as follows:The fluid transport mechanics of drug delivery through an array of micro needle is investigated and models for capillary blood flow and capillary flow are established. The micro fluidics in micro channels which is characterized by lotus effect is discussed by NEMD (Non Equilibrim Molecular Dynamics) simulation. The NEMD simulation can improve the importance of the remodeling surface in theory. The insulin solution and silicon oil flow experiments prove that the micro channel surface which is remodeled by silicane is more slippery than those of the normal.After reviewing the progress of the micro needle, the straight wall, out of plane, hollow micro needle is designed and fabricated based on MEMS technology. The micro needle array is used to rapidly induce drug into tissue under the skin. And micro needle array is realized with the material of silicon which is well known biocompatible, with the size of 9mm×9mm, 30μm in inner diameter, 80μm in outer diameter, 200μm in length, and 250μm in space.The micro needle array is fabricated by MEMS technology. Processes of boring high aspect ratio hole in silicon substrate and etching needle tip are introduced in detail. We present the development of this novel technology which can enable the realization of micro fabricated micro needle array on a flexible silicon substrate which is proved by bending test. No contamination, leak free packaging is studied and packaging materials are biocompatible to most medicine and proved no poison to life.A closed-loop controlled insulin delivery system based on MEMS technology is studied. The system is made up of gloucse monitor and insulin pump. The MEMS technology makes the system minimize and consume less power. The diabetes therapy is programmed according to bionic principle and several professional therapy schemes for special diabetes such as children and pregnant women are presented. Experiments of transdermal insulin delivery on rat and bird skins are investigated. Animal tests prove that the close-loop controlled insulin bump has wide application on diabetes care.The paper aims at providing a closed-loop controlled insulin delivery system which based on MEMS technology, and pushing the research and commercialization of Bio-MEMS devices.