Pharmaceutical and therapeutic applications of artificial cells including microencapsulation

Artificial cells for pharmaceutical and therapeutic applications started as microencapsulation on the micron scale. This has now expanded up to the higher range of macrocapsules and down to the nanometer range of nanocapsules and even to the macromolecular range of cross-linked hemoglobin as blood substitutes. This author first reported microencapsulation of biologically active material in 1957 (T.M.S. Chang, Hemoglobin corpuscles. Research Report for Honours Physiology, Medical Library, McGill University, 1957. (Also reprinted as part of 30th anniversary in Artificial Red Blood Cells Research, J. Biomater. Artif. Cells Artif. Organs 16 (1988) 1-9.) and 1964 (T.M.S. Chang, Semipermeable microcapsules, Science 146 (1964) 524-525). While pharmaceutical research has made use of these approaches for drug delivery, this author has been concentrating on the encapsulation of biotechnological products for therapeutic applications. Therefore, there was little interaction between the two approaches. In the last 10 years, pharmaceutical research, as in other areas of research, has become increasingly interested in biotechnology. Because of this interest, this article is a brief overview of developments of artificial cells for biotechnological products with emphasis on hemoglobin, enzymes, cells and genetically engineered microorganisms.