<p>A device which serves as an artificial pancreas comprises a hollow fiber having an inner diameter of about 5 mm which is surrounded by islets of Langerhans enclosed in a housing. The islets are suspended in a semi-solid matrix which ensures desired distribution of the cells about the hollow fiber. The hollow fiber and suspended islets are enclosed in a housing which further aids the desired distribution of islets about the hollow fiber. The hollow fiber has a porosity which selectively allows passage of substances having a molecular weight of less than about 100,000 Daltons. The semi-solid matrix in which the islets are embedded and suspended is formed of an appropriate supporting material such as alginate or agar.</p>
