Artificial pancreas device systems

The closed-loop system (often termed the artificial pancreas ) is essentially a more sophisticated version of the system described above. It consists not only of a pump and infusion device, but also of an integral glucose sensor and computer that analyses the blood glucose data obtained and adjusts the flow rate accordingly. The true potential of such systems remains to be assessed. 

The closed-loop type artificial pancreas (specifically 8-cell), which consists of an automatic continuous monitor of blood glucose level (BGL) and an automatic injector of insulin which are coupled with feed-back system, has great potential for prevention of diabetic complication such as micro-angiopathies(l). A large-scale closed-loop type artificial pancreas for bedside use has already been developed and is clinically used at some laboratories and hospitals (2-4). However, this device is limited to only bedside use. On the other hand, the open-loop type artificial pancreas which consists of only a insulin injecting pump without an automatic continuous monitor of BGL, has been developed and is going to be clinically used(5-7). This system, however, can not completely control BGL as well as the bare pancreas in a normal body and often causes lower BGL(8-9). 

Cells may also be cultured within or on the outside of hollow fiber exchange devices and a patient s blood may be circulated through the device for treatment of various diseases (e.g., using pancreatic beta cells for diabetes patients in an "artificial pancreas," or using liver cells in an "artificial liver" during hepatic failure). Table IV lists some general examples of biomedical uses of immobilized biomolecule or cell systems. 

The second system, based on polymer 24 is water-soluble as its sodium salt, but crosslinks ionically in the presence of di- or tri-valent cations such as calcium or aluminum ions [43], to form hydrogels. This polymer Is under development as a component for the microencapsulation of hybridoma mammalian cells to allow their use in prototype artificial liver or pancreas devices, or in biotechnology [44-46]. 

Examples of analogous complete systems in chemistry are still rare. The best example is perhaps the artificial pancreas, in which a glucose sensor measures the actual blood-glucose concentrations in order to control an appropriate actuator, the insulin pump. Bedside devices for this purpose... 

In more sophisticated drag deUvery systems the gel can sense conditions inside the body and t ry the rate of delivery. An example is an artificial pancreas representing a device capable of secreting insulin in response to a change in the glucose concentration. 

A microcapsule is a minature membrane system in which the combination of high permeability and large surface area can confer some unusual properties and have made microcapsules of interest for drug release systems and for some artificial organs. Hundreds of different materials have been enclosed within microcapsules for both biomedical and non-medical use. The classic non-medical example would be the carbonless "carbon" papers which are in wide use today. Medically, microcapsules have been used to enclose various enzymes, such as catalase or L-asparaginase (which can be used to treat some forms of cancer), and have been shown to maintain the enzymatic activity for prolonged time periods. Microcapsules have been utilized as artificial cells to enclose the beta-cells from the Islets of Langerhans, and such a system can function as a source of insulin (artificial pancreas). i Other research has centered on the use of such devices for artificial red blood cells. ... 

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