Mammalian cell traces - morphology, molecular composition, artificial guidance and biotechnological relevance as a new type of "bionanotube"

During locomotion, adherently growing cells release highly ordered structur es consisting of filaments: and patches often dendritically organised. Such traces can be re-incorporated by the donor cell or disconnected and lost. Here, we present the results of a three-year research programme into trace formation and structural organisation including the influence of substrate surface properties. Some phenomena may, ultimately, have medical or technol ogical applications. These include: (i) the deposition and re-incorporation of cellular material as cells move forward and backward; (ii) the ability of cells to differentiate between their own and foreign traces; (iii) the p resence of receptors in the intact membrane envelope of filaments and patch es; and (iv) the cytoplasmic content of patches. Trace formation is physiol ogically controlled and a characteristic of many types of actively migratin g higher animal and human cells. Possible applications and perspectives are discussed and the importance of cell-trace elements as "bionanotubes" and biological submicron compartments of cells is explained.